AGCO ST28A Tractor 28 hp Overview, Features, and Performance Specs
AGCO ST28A Tractor 28 Hp
The AGCO ST28A is a compact tractor built for small farms, landscaping, and property work. You get a naturally aspirated, 1.5-liter diesel engine that gives you around 28 horsepower at 2,500 rpm.
You can choose between hydrostatic and gear-driven transmissions. This lets you match the tractor to your jobs, whether it’s mowing, hauling, or tilling.
PTO power ranges from about 22 to 25 hp, giving you flexibility with attachments. Hydraulics are reliable and give enough flow for most small implements.
The tractor is 4WD, offering better traction on rough or muddy ground. Weighing about 2,700 lbs, the ST28A is stable for loader work or towing.
Maintenance is straightforward with accessible engine parts and filters. Many parts for the ST28A are shared with the Massey Ferguson 1528, making it easier to find replacements.
Here is a table summarizing important details:
| Feature | Specification |
|---|---|
| Engine Type | Diesel, naturally aspirated |
| Engine Power | 28.4 hp (gross) |
| PTO Power (Hydro/Gear) | 22.3 / 24.5 hp |
| Displacement | 1.5 L (89 cu in) |
| Transmission Options | Hydrostatic / Gear |
| Drive | 4WD |
| Weight | ~2,700 lbs |
| Hydraulic System | Standard, suitable for implements |
| Common Attachments | Loader, mower, tiller, backhoe |
| Comparable Model | Massey Ferguson 1528 |
You can use the AGCO ST28A for tasks like mowing fields, moving dirt, and even light construction. The compact size helps when working in tight areas.
You get multiple PTO and hydraulic options, making the ST28A useful with a wide range of implements. The controls are simple and positioned for easy use, which helps if you are new to tractors.
If you need parts or manuals, you can also check resources for the Massey Ferguson 1528 since they share many components.
Production & Identification
The AGCO ST28A tractor is known for its compact size, reliable performance, and its connection to well-established brands and manufacturers. Accurate identification is important for service, parts, and resale value.
| Topic | Details |
|---|---|
| Manufacturer / Brand | AGCO (distributed), Iseki (producer) |
| Model Number / Series | ST28A, Part of the ST-A Series (ST22A, ST24A, ST33A, etc.) |
| Factory Of Manufacture | Matsuyama, Japan |
| Years Produced | 2005 – 2008 (ST-A Series era) |
| Original List Price | Information not widely published, estimate mid-2000s compact range |
| Serial-Number Location | Stamped on main tractor frame, usually near the front axle, left side |
Manufacturer / Brand
You will find that the AGCO ST28A tractor was both distributed and branded by AGCO, a major player in the agricultural equipment sector. While AGCO is widely recognized for its broad distribution network in North America, the actual design and construction of the ST28A was handled by Iseki, a leading Japanese manufacturer.
Iseki specializes in compact and utility tractors and has a long-standing reputation for producing reliable, efficient equipment. AGCO partnered with Iseki to source several compact models for the ST series, including the ST22A, ST24A, and ST33A.
The tractor may carry AGCO branding on the hood and in documentation, but you will often see Iseki identification plates or markings on certain parts, especially in the engine compartment.
Model Number / Series
The model number for this tractor is ST28A. This number clearly places it within AGCO’s ST-A series of compact utility tractors.
The series includes models with different power ratings: ST22A, ST24A, ST28A, and ST33A. You can identify the model number on decals located on the tractor’s hood or its side panels.
The ST28A designation indicates a tractor with approximately 28 horsepower. The ST-A series was designed to offer small to mid-sized utility tractors for various applications, ranging from landscaping to light farming.
Each model in the ST-A series shares several features and components. However, the ST28A stands out for its balance between power and versatility.
This makes it suitable for users who need more capacity than a sub-compact tractor offers, but who do not require a full-size machine.
Factory Of Manufacture
Manufacturing of the AGCO ST28A took place in Matsuyama, Japan. This factory was operated by Iseki.
Iseki is known for building high-quality, reliable tractors for both domestic Japanese and export markets. The Matsuyama facility is highly automated and known for its precision assembly processes.
If you look at the build plate or documentation, you will often see “Made in Japan” included. All compact ST-A series tractors shipped from this factory to AGCO were fully assembled.
The strict quality standards at Matsuyama benefit buyers looking for robust and long-lasting equipment.
Years Produced
You should know that the AGCO ST28A was primarily produced between 2005 and 2008. This timeframe matches the main production run for the AGCO ST-A series (which includes ST22A, ST24A, ST33A).
Production years are important for matching parts and understanding technological updates. The early- to mid-2000s models typically used Tier 2 emissions engines, basic but sturdy electronics, and mechanical controls.
Any units manufactured after 2008 are rare, and most were sold by the end of that decade. If you are hunting for a used ST28A, checking the year of manufacture against the serial number will help you avoid confusion with earlier ST series models or the similar Iseki-branded units.
Original List Price (Launch Year)
The original list price for the AGCO ST28A at launch is not widely published in official company literature. However, based on dealer archives and pricing of comparable tractors from the mid-2000s, you could expect a new ST28A to retail between $13,000 and $16,000 USD.
Price variations were common and depended on included options such as loaders, cabs, or four-wheel-drive (MFWD). The ST28A was positioned to offer value and features in line with its ST-A series siblings, providing more capability than the smaller ST22A and ST24A, but at a lower cost than the largest ST33A.
This price placed the ST28A solidly in the compact utility tractor market of its time, appealing to small acreage owners, landscapers, and commercial operators.
Serial-Number Location
Identifying the correct serial number is key for maintenance and resale value. On the AGCO ST28A, you will typically find the serial number stamped into the left side of the main frame, above or near the front axle.
You may also see an identification plate or sticker placed near the engine or inside the operator’s platform, but the frame stamping is the primary, official location. It’s important to match this number with the number in your owner’s manual and any service records.
Be sure to clean the area before checking, as the stamping can become hidden by mud or debris. This number lets you determine the manufacturing year and helps with correct parts ordering.
Engine Specifications
The AGCO ST28A uses a robust diesel engine designed for reliability and efficiency in light to medium-duty work. You can expect information on engine make, fuel, displacement, rated horsepower, torque, compression, and cooling capacity.
| Feature | Specification |
|---|---|
| Engine Make & Model | Mitsubishi S3L2 |
| Fuel Type & Emissions Tier | Diesel, Tier 2/Stage II (est.) |
| Cylinders / Displacement | 3-cylinder, 1.5 L (1,463-1,500 cc) |
| Rated Horsepower (Gross/Net) | 28.4 hp (21.2 kW) / ~27 hp (est.) |
| Peak Torque (Nm @ Rpm) | ~85-90 Nm @ 1800-2200 rpm (est.) |
| Compression Ratio | 22:1 (est.) |
| Cooling System & Capacity | Liquid, approx. 6.5-7.0 qts (6.2-6.6 L) |
Engine Make & Model
You have a Mitsubishi S3L2 engine under the hood of your AGCO ST28A. This is a 3-cylinder diesel engine, known for its dependability in compact tractors.
Mitsubishi engines are favored in the industry for their smooth running and durability. The S3L2 model runs quietly and delivers consistent performance, which helps you get steady power whenever you need it.
Parts and service are also widely available due to Mitsubishi’s global presence in machinery and compact utility equipment.
Fuel Type & Emissions Tier
The AGCO ST28A is powered by diesel fuel, which is the standard for compact tractors in its class. Diesel engines like the S3L2 offer better fuel efficiency and more torque compared to gasoline-powered options.
This model is designed to meet Tier 2/Stage II emissions standards. Tier 2 standards focus on reducing emissions of nitrogen oxides (NOx) and particulate matter.
You won’t find advanced emission control systems like diesel particulate filters on this engine, but the basic design keeps emissions manageable and keeps the tractor simple to maintain.
Cylinders / Displacement
Your tractor features a 3-cylinder engine. The total displacement is about 1.5 liters, or around 1,463 cubic centimeters (cc).
Three-cylinder configurations like this balance power output with fuel economy and compactness. The cylinders are arranged inline, reducing vibration and delivering power smoothly.
The engine’s displacement helps provide the 28.4 gross horsepower that allows the ST28A to handle a wide variety of tasks, from mowing to loader work.
Rated Horsepower (Gross & Net)
The AGCO ST28A’s engine is rated at 28.4 gross horsepower (21.2 kW) at 2,500 rpm. This is the maximum power output the engine can deliver before subtracting losses from accessories like the alternator and fan.
Net horsepower is slightly lower, usually around 27 hp, as it accounts for power used by engine-driven systems. PTO (power take-off) horsepower is measured at the shaft.
Gear models can deliver up to 24.5 hp at the PTO, while hydrostatic models are a little lower due to transmission losses.
Peak Torque (Nm @ Rpm)
Diesel engines are known for producing strong torque at low rpm. The Mitsubishi S3L2 engine produces an estimated peak torque of about 85-90 Newton-meters (Nm) at around 1,800 to 2,200 rpm.
Strong torque at lower rpm means you get pulling power for jobs like tilling or loader work, without having to rev the engine high. This also helps prolong engine life and improves fuel efficiency.
Exact figures can vary slightly, but the performance is steady and reliable across most tasks.
Compression Ratio
The engine uses a high compression ratio, estimated at around 22:1. High compression is typical for small diesel engines.
This helps increase thermal efficiency, allowing your tractor to extract more energy per drop of fuel. High compression ratios are a key reason why diesel engines have better fuel economy and can deliver higher torque at low speeds compared to engines using gasoline.
This setup supports stronger ignition, which is needed for diesel combustion that happens without spark plugs.
Cooling System & Capacity
The AGCO ST28A is equipped with a liquid cooling system. The coolant helps manage engine temperature, especially under heavy loads or during long periods of operation.
Coolant capacity is around 6.5 to 7.0 quarts (about 6.2 to 6.6 liters). This is typical for engines of this size and helps prevent overheating.
Routine checks and maintenance of the cooling system are important. Proper fluid levels and a clean radiator ensure the engine remains at the correct temperature for maximum efficiency and lifespan.
Power Take-Off (PTO)
The AGCO ST28A’s PTO system is a key feature for many types of attachments. These systems support rear and optional mid-mount accessories, making the tractor versatile for mowing, tilling, or other jobs.
Claimed PTO Horsepower
The PTO horsepower on the AGCO ST28A varies slightly depending on the transmission you are using.
With hydrostatic transmission, the PTO is rated around 22.3 hp (16.6 kW). With a gear-driven transmission, the PTO rating can reach 24.5 hp (18.3 kW).
This output allows you to run many common implements, including rotary cutters and mowers. You should match your implement’s required PTO horsepower with what your tractor delivers.
Overloading the PTO can damage both the attachment and your tractor. Make sure you check both the implement’s manual and the ST28A’s specs before use.
Hydrostatic transmissions tend to deliver slightly less PTO power because of the energy they use, but they offer smoother control. For tasks needing maximum PTO power, the gear-driven version gives you a small but useful advantage.
PTO Type (Independent / Live / Economy)
The AGCO ST28A offers two main PTO types, depending on your transmission:
- Transmission (Gear-Driven): This type is controlled by the clutch. The PTO works only when the tractor is moving and the clutch is engaged.
- Independent (Hydrostatic): This version uses its own control, separate from the drive clutch. You can start or stop the PTO without affecting tractor motion.
Independent PTO is useful when you need to control the implement separately, such as when mowing in tight areas or clearing around obstacles. It’s also safer and more convenient for frequent starts and stops.
Some models also offer an optional mid-mount PTO, allowing you to power mid-mount mowers or other specialty tools. This adds another layer of versatility to your tractor if you need to handle lots of yard or grounds maintenance.
PTO Speeds (540 / 1 000 Rpm)
The standard rear PTO speed for the AGCO ST28A is 540 rpm. This is the most common speed in compact tractors and is compatible with most implements such as mowers, post hole diggers, and tillers.
The shaft size for the rear PTO is 1.375 inches, which is a typical standard for compact tractors. This makes sourcing and attaching equipment easier.
An optional mid PTO is also available. This system is usually used for mid-mount mowers and runs independently from the rear PTO.
The specific speed for the mid PTO can vary, so check your tractor’s manual and the implement requirements before connecting. Some models do not offer a 1,000 rpm rear PTO, so if you have larger or special implements, check compatibility first.
PTO System Summary Table
| Feature | Gear Drive Version | Hydrostatic Version | Mid-Mount PTO Option |
|---|---|---|---|
| PTO Horsepower | ~24.5 hp (18.3 kW) | ~22.3 hp (16.6 kW) | N/A |
| PTO Type | Transmission (Clutch) | Independent | Independent |
| Rear PTO Speed | 540 rpm | 540 rpm | — |
| Mid PTO | Optional | Optional | Standard |
| Typical Uses | Rear implements (tillers, blades, etc.) | Mowers, various attachments | Mid-mount mowers |
Transmission & Drivetrain
The AGCO ST28A comes equipped to handle a wide range of jobs with its versatile transmission, reliable drivetrain options, and useful features like four-wheel drive and differential lock.
Each part works together to improve traction, stability, and ease of use when operating in fields, on turf, or along roads.
| Feature | Details |
|---|---|
| Transmission Types | Hydrostatic (HST), 9-speed Manual |
| Number of Gears/Ranges | 9 Forward, 3 Reverse, 2 Ranges |
| Top Transport Speed | Varies by transmission, usually 12-15 mph |
| Drive Options | 2WD, 4WD (Selectable) |
| Differential Lock | Mechanical, Foot-Operated |
| Final Drives | Planetary Gear Type |
Transmission Type (Syncro, Powershift, CVT, HST)
The AGCO ST28A offers two primary transmission types.
You can find a hydrostatic transmission (HST), which uses fluid pressure for smooth, step-less speed control. This is good for loader work and jobs needing quick changes of speed or direction.
Instead of manual shifting, you use foot pedals for forward and reverse, making driving easier and less tiring. There is also a 9-speed manual gearbox on some models.
This is a traditional gear system where you select the speed and direction using a gear lever and clutch. It is simple and dependable, and it gives you better power control if you plan to do heavy pulling or tillage.
Each type is robust and built to handle regular use. Both options focus on giving you direct power from the engine to the wheels with as little loss as possible.
Number Of Gears / Ranges
The manual transmission features 9 forward gears and 3 reverse gears. You also get 2 selectable ranges—usually “high” and “low.”
This setup gives you a wide choice of operating speeds. You can pick a lower gear and range for jobs needing slow movement, like heavy pulling or mowing thick grass.
The higher gears and range are used for transport or covering ground faster. If you have the hydrostatic transmission, you get infinite speeds within its high/low ranges.
This means you aren’t limited to set gear slots and can adjust speed precisely using foot controls. This flexibility allows you to match the speed to your needs, whether you’re working in tight spaces or moving between tasks in different areas.
Top Transport Speed
Top transport speed mainly depends on which transmission your AGCO ST28A is fitted with.
For the manual 9-speed gearbox, you can usually reach speeds around 12–15 mph (19–24 km/h) in the highest gear and range. This is fast enough for moving between fields or along roads for short distances without slowing down traffic too much.
With the hydrostatic transmission, top speed is similar but controlled with the pedal rather than with a gear lever. Hydrostatic setups sometimes have a slightly lower max speed, prioritizing smooth and easy speed adjustment over outright pace.
You can safely move equipment and tow light implements at these speeds. This makes transport tasks efficient.
Drive (2WD / 4WD / AWD)
The AGCO ST28A is available in both two-wheel drive (2WD) and four-wheel drive (4WD) versions.
4WD is selectable on many models, giving you better traction and stability on loose or wet ground. If you are working in mud, sand, snow, or on hills, four-wheel drive helps prevent getting stuck or losing control.
When you do not need 4WD—like on dry, solid ground—you can switch back to 2WD to save fuel and reduce tire wear. You can select between 2WD and 4WD using a simple lever.
All-wheel drive (AWD) is not present, but the 4WD is more than adequate for most farming or landscaping jobs. This lets you handle challenging terrain and heavy work with confidence.
Differential-Lock & Final Drives
The differential-lock is usually engaged with your foot via a dedicated pedal. When active, it forces both rear wheels to spin at the same speed.
This helps if one wheel is slipping in mud or on wet grass, giving you steady traction. You can engage the differential lock while moving slowly, especially helpful when pulling out of a soft spot or climbing a slippery hill.
Once traction improves, you release the pedal to return to standard driving. The final drives on the AGCO ST28A use a planetary gear system.
These gears are strong and designed to handle high loads without extra maintenance. The system spreads the force evenly to the axles, reducing wear and giving you durability during tough jobs.
Steering & Brakes
The AGCO ST28A uses hydrostatic power steering to provide easier handling. Its wet disc brakes help with control even on hills or in wet environments.
| Feature | Type/Details | Key Advantages |
|---|---|---|
| Steering System | Hydrostatic power steering | Light, precise control |
| Turning Radius (with brakes) | Tight for maneuvers | Improved in narrow spaces |
| Service Brakes | Wet disc brakes | Durable, reliable in wet/mud |
| Parking Brake | Mechanical, often lever-controlled | Prevents rollaway on slopes |
Steering System (Hydrostatic / Power-Assisted / Mechanical)
You control the AGCO ST28A with hydrostatic power steering. This system uses hydraulic force to assist your turning, making it much lighter than manual steering.
You do not need to wrestle with the wheel, even when the tractor is fully loaded or moving slowly. Hydrostatic steering improves maneuverability in tight spots, like barns or small fields.
It lets you react quickly without needing a lot of muscle. The wheel response stays smooth and steady, which helps prevent fatigue if you spend a long time driving.
Because the system is sealed, it resists dust and dirt and requires less maintenance than some mechanical setups. This keeps your steering system reliable and consistent under many types of weather and ground conditions.
Turning Radius (With Brakes)
When you use the brakes, you can make even sharper turns. The AGCO ST28A is designed to handle tight areas commonly found on small farms or landscaping jobs.
Using the individual wheel brakes lets you pivot and maneuver around close obstacles or corners. This tighter turning radius helps when you need to line up for fieldwork or get around livestock pens.
You only need a small space to turn, making tasks like mowing or tilling more efficient in confined spots. The precise brake-assisted turn is especially useful if you work in rows, orchards, or gardens.
It reduces the number of passes you need to make and saves time.
Service Brakes (Wet Disc, Dry Drum, Etc.)
The service brakes on the AGCO ST28A are wet disc brakes. This means the brake discs are kept in oil, which helps them stay cool and last longer.
Wet disc brakes are less likely to fade or lose effectiveness compared to dry drum types, especially after frequent use. You get consistent stopping power even in mud, rain, or when going downhill.
Wet disc brakes are self-adjusting and require less maintenance since they are not exposed directly to dirt and contaminants. These brakes are designed with durability and reliability in mind, fitting the needs of most operators who use their tractor year-round.
Parking Brake Type
The AGCO ST28A uses a mechanical parking brake, usually controlled by a hand lever. When you set the brake, it locks the wheels so the tractor cannot roll.
This is especially important when you park on slopes or need to leave the tractor unattended on uneven ground. The mechanical brake is simple to operate—pull the lever to set and release.
It relies on a physical linkage rather than hydraulics or electronics, making it dependable even if the tractor loses power. Because the parking brake is independent from the service brakes, it acts as an important safety feature anytime you leave your seat.
You reduce the risk of accidents or the tractor moving unexpectedly.
Cab & Operator Station
Operator comfort and safety are key when using the AGCO ST28A Tractor. You should pay close attention to cab structure, controls, and the features that can impact your work environment.
| Feature | Details |
|---|---|
| ROPS / Cab Option | Standard ROPS, no fully enclosed cab |
| Climate Control | No factory air conditioning; basic heater option may be available |
| Seat & Suspension | Basic adjustable seat, mechanical suspension |
| Noise Level (dB A @ Operator Ear) | Not specified, typically between 80-85 dB(A) for open station models |
ROPS / Cab Option
The AGCO ST28A comes equipped with a ROPS (Roll Over Protection Structure) as standard. This provides vital protection to you in case of a tip or rollover.
There is no fully enclosed cab on this model, so you will be exposed to weather and outside conditions during operation. The open station design means quick access to controls and easy mounting or dismounting the tractor.
You may find optional sun canopies offered by some dealers, giving shade but not full protection from rain or wind. Since there is no glass enclosure, keeping warm or dry depends on clothing and attachments rather than the tractor itself.
Climate Control (A/C, Heater, Filter)
AGCO ST28A tractors are not fitted with factory air conditioning or advanced filtration systems. Open station tractors like these rely on natural ventilation.
A heater may be available as an add-on or through aftermarket solutions. The heater can help keep you a bit warmer in cold weather, but it does not offer the same comfort as a climate-controlled cab.
Dust and pollen filters are not included since the operator station is open. Make sure to wear suitable protective gear if working in dusty or allergy-prone environments.
Seat & Suspension
The seat offered on the AGCO ST28A is adjustable for position and angle. This helps provide a more secure and comfortable fit for operators of different sizes.
The seat typically uses a mechanical suspension system to absorb minor shocks and bumps. You will not find advanced air-ride or high-back seats as standard.
The padding provides basic comfort but may become less comfortable in prolonged or rough use. Armrests and lumbar support are limited or not included, so some users may wish to consider aftermarket seating solutions.
Seat material is easy to clean, which is important on an open tractor since seats can get wet or dirty easily.
Noise Level (dB A @ Operator Ear)
Noise levels on the AGCO ST28A are not officially specified. You should expect open station compact tractors like this to produce between 80 and 85 decibels at the operator’s ear.
There are no sound-reducing panels or insulation on this tractor. Operation for long hours may require hearing protection to prevent fatigue or hearing loss.
Engine and hydraulic sounds are more noticeable due to the lack of an enclosed cab. The environment you work in, such as the presence of nearby buildings or trees, can influence your experience of noise on the tractor.
Hydraulics
The AGCO ST28A tractor uses an open-center hydraulic system with a pump flow rate designed for small implements and loader work. Key figures include a main pump flow of 7.4 gallons per minute (28.0 liters per minute) and typical support for one or two remote valves.
| Feature | Specification |
|---|---|
| System Type | Open-Center |
| Implement Pump Flow | 28.0 L/min (7.4 gal/min) |
| Steering Pump Flow | Integrated with main pump |
| Total Combined Flow | 28.0 L/min (7.4 gal/min) |
| System Pressure | Info commonly not published |
| Remote Valves (Number & Type) | 1-2, typically single-acting |
System Type (Open-Center / Closed-Center / PFC)
The ST28A uses an open-center hydraulic system. Hydraulic oil constantly circulates through the pump and valves when the system is operating.
Open-center systems are common on compact tractors because they are simpler to maintain and repair. With an open-center setup, the system performs well under light to moderate loads but can be less efficient with many simultaneous hydraulic functions.
These systems are best for loader work, using basic attachments, and for general utility tasks. Closed-center or pressure-flow compensated (PFC) systems are rarely found on models of this size.
Implement Pump Flow (L Min⁻¹)
The main implement pump provides a flow rate of 28.0 liters per minute (7.4 gallons per minute). This flow is suitable for compact tractor implements such as small loaders, back blades, and box scrapers.
With 28.0 L/min, you can power a loader bucket efficiently for digging, lifting, and other utility work. This flow supports smooth operation of implements but may be limited for high-demand, commercial-grade tools.
The loader bucket capacity will depend on the loader model fitted. This pump flow is usually enough for bucket sizes typical of sub-30 horsepower tractors.
Always check implement manuals for flow requirements.
Steering Pump Flow (If Separate)
The steering system on the ST28A uses hydrostatic power, supplied by the same pump as the main hydraulic system. There is not a dedicated, separate pump just for steering.
Hydrostatic power steering provides easy and precise control while turning. Steering performance remains reliable as long as there is enough oil and the hydraulic system is working well.
Even during loader work or when using rear implements, the steering stays powered because the system is designed to prioritize steering needs.
Total Combined Flow
Because the ST28A uses a single hydraulic pump for both implement and steering circuits, the total combined flow is 7.4 gal/min (28.0 L/min). All hydraulic functions share this capacity.
If you are operating several hydraulic functions at once, the speed of each can be affected since they share the available flow. Tasks such as steering and loader use are balanced by the tractor’s open-center system to avoid serious slowdowns.
If you plan to use attachments requiring very high hydraulic flow, you will want to check compatibility.
System Pressure (Bar / Psi)
The typical system pressure for this type of compact tractor open-center system is between 150 to 180 bar (about 2,200 to 2,600 psi). For the AGCO ST28A, the exact published figure is not always provided.
This level of pressure is enough to lift a loader bucket full of material, operate small hydraulic cylinders, and power attachments like log splitters or rear blades with hydraulic functions.
Pressure works with flow to determine the strength and speed of hydraulic tools. Make sure the hoses and implements you use are rated for at least the system maximum pressure.
Remote Valves (Number & Type)
Remote hydraulic valves let you power external implements. On the ST28A, 1 or 2 remote valves are common depending on dealer setup and options.
These valves are usually single-acting. They can raise or lower a cylinder but may not offer full double-acting operation for more complex attachments.
For advanced tools needing multiple or double-acting remotes, additional valve kits may be needed. Always check your current valve setup before buying new implements.
Three-Point Hitch (3PH)
The AGCO ST28A features a well-equipped three-point hitch system that lets you attach a range of implements for different jobs. Understanding this system’s main features helps you get the most out of your tractor for fieldwork, mowing, or lifting tasks.
Hitch Category (1 / 1N / 2 / 3)
Your AGCO ST28A comes with a Category I three-point hitch. This category is common for compact and utility tractors in the 20-50 horsepower range.
Category I hitches are compatible with many implements made for small and mid-sized tractors.
Here are the main specifications:
| Feature | Details |
|---|---|
| Hitch Category | Category I |
| Pin Diameter | 7/8 inch (22.2 mm) |
| Lower Link Size | 7/8 inch |
| Top Link Size | 3/4 inch |
You can easily find compatible mowers, tillers, blades, or other tools at most farm supply stores. The hitch arms are spaced about 26 inches apart (lower point width), making it straightforward to attach most standard Cat. I implements.
Lift Capacity @ Ball Ends
The ST28A’s Category I three-point hitch has a max lift capacity of up to 1,609.4 pounds at 24 inches behind the lift point. This is enough for a wide variety of heavy-duty implements that match the tractor’s power.
| Measurement | Capacity |
|---|---|
| Lift Capacity @ 24″ behind lift pt | 1,609.4 lbs (730 kg) |
| Lift Capacity @ ball ends (approx) | Similar or slightly higher |
You can handle several tasks, like lifting soil, transporting feed, working with landscape rakes, or pulling plows. Always check your specific implement’s weight before attaching it, as going above the lift limit may damage the system or make lifting unsafe.
Draft / Position Control
The three-point hitch on the ST28A includes position control. With position control, you can set and maintain the height of your implement, which is helpful when grading, cultivating, or mowing.
You simply move the control lever to the desired setting, and the hitch will raise or lower the implement to that exact position. The ST28A does not have draft control.
- Position Control: Lets you choose the exact height for attached implements
- Draft Control: Not included on the ST28A
- Benefits of Position Control: Precise height adjustment for repeated passes
Top-Link Sensing (Yes/No)
The ST28A does not have top-link sensing. Top-link sensing is usually found on larger agricultural tractors and is used in draft control systems.
Since the ST28A does not have draft control, top-link sensing is not included.
For your ST28A, the top link is adjustable in length to help you level or tilt your implement. Always check the connections and adjustments before starting work to make sure the implement operates smoothly and safely.
| Feature | Included |
|---|---|
| Top-Link Sensing | No |
| Adjustable Top-Link | Yes |
You can make the needed adjustments manually to suit your task and implement requirements.
| Subsection | Hitch Category | Lift Capacity | Draft/Position Control | Top-Link Sensing |
|---|---|---|---|---|
| AGCO ST28A Specification | Category I | 1,609.4 lbs @ 24″ | Position Control Only | No |
| Key Pin Sizes | 7/8″ (Lower), 3/4″ (Top) | — | — | — |
| Control Feature | — | — | Height Selection Only | Manual Adjust |
| Compatible Implements | Most Cat. I | Under 1,600 lbs | — | Yes (manual adj.) |
Axles & Load Limits
Studying axle weights and the type of final drive is important for safe tractor operation and maintenance. The AGCO ST28A’s axle and load limits matter most when hauling materials or using heavy implements.
| Specification | Value/Detail |
|---|---|
| Maximum Front-Axle Load (Kg) | Not specified |
| Maximum Rear-Axle Load (Kg) | Not specified |
| Final-Drive Type | Four-wheel drive (4WD), planetary gear reduction (industry typical) |
| Tractor Total Weight | 1,000 kg (2,205 lbs) |
Maximum Front-Axle Load (Kg)
The maximum front-axle load for the AGCO ST28A isn’t specifically listed in available manuals or datasheets. Total tractor weight is 1,000 kg (2,205 lbs), and the front axle is designed to support front-end loaders and heavy attachments.
It’s best to stay within the physical design limits provided by AGCO for implement use. Overloading the front axle can cause premature wear or damage to joints, bearings, and steering components.
When using a front loader or front-mounted equipment, you can improve stability by adding ballast or wheel weights to the rear for balance. Always follow the manufacturer’s recommendations for total and axle weight distribution.
If you add heavy attachments, check the load by calculating the attachment weight plus the tractor’s own front weight. Avoid exceeding values that could impact safe steering or braking.
Maximum Rear-Axle Load (Kg)
There is no listed maximum load for the rear axle in public sources. The rear axle on the ST28A must handle the combined weight of the tractor and any rear-mounted implements, such as mowers or tillers.
You need to avoid carrying loads that will stress the axle, especially when using lift arms or a three-point hitch. Too much weight can damage the differential, axles, or PTO components.
Keep in mind the overall tractor weight and use counterweights as needed, especially when lifting with the front loader. Distribute any added weight carefully to avoid imbalance when carrying implements.
Final-Drive Type
The AGCO ST28A uses a four-wheel drive system. This model likely features a planetary gear reduction in the final-drive assembly, a system common in compact tractors.
Final drives transfer engine power to the wheels and help the tractor handle tough ground conditions. In 4WD mode, power is sent directly to both front and rear axles, which improves traction.
Planetary gears increase torque to the wheels while cutting down on stress to the drive shafts. This setup gives you smoother operation and better control in wet, loose, or sloped terrain.
Regular checking and maintenance of axle seals, fluid levels, and drive components will keep your tractor running well.
Tires & Track Options
You have a range of tire and track options to help match the AGCO ST28A Tractor to your ground conditions. The choices you make here can impact traction, soil compaction, and comfort during use.
Standard Front Tire Size (Ag / Turf / Industrial)
The front tires on the AGCO ST28A are available in agricultural (Ag), turf, and industrial types. Standard Ag front tires are sized to provide good traction in soil and are often 6-12 or similar.
You may find turf tires like 23×8.50-12, which have a wider and smoother profile to minimize grass damage in lawn and turf applications. Industrial front tires are usually more robust, with sizes such as 23×8.50-12, but feature a heavier tread pattern to handle gravel or hard-packed surfaces.
Choosing the right front tire ensures steering control and reduces wear, especially if you use the loader or work on soft ground.
Standard Rear Tire Size
The rear tires play an important role in traction and pulling power. Standard Ag rear tires for this tractor are typically close to 9.5-16, delivering deep treads for field work.
Turf tire options like 33×12.50-16.5 are available, with a rounder pattern for less surface disruption. Industrial rear tires provide additional durability and sometimes a heavier sidewall for loader work or hard surfaces.
The correct rear tire selection depends on your primary use cases, from mowing to tillage or loader operation.
Standard Rear Tire Size Comparison Table:
| Tire Type | Common Size | Tread Pattern | Ideal Use |
|---|---|---|---|
| Ag | 9.5-16 | Deep-lug | Fields, soil |
| Turf | 33×12.50-16.5 | Smooth, rounded | Lawns, parks |
| Industrial | 12-16.5 | Heavy tread | Mixed, hard ground |
Optional Duals / Tracks / Flotation Kits
Your AGCO ST28A can be outfitted with special wheel options to suit challenging conditions. Dual wheels on the rear can be installed for extra traction in muddy or slippery fields, spreading out the weight and reducing soil compaction.
While factory tracks are not standard on this compact model, aftermarket track kits are available for extreme soft-soil performance. Flotation kits, which include wider or lower-pressure tires, help keep the tractor from sinking into soft ground.
These are especially useful in wet fields or delicate turf. Adding these options can improve performance during planting seasons or on jobs where compaction must be minimized.
| Option | Availability | Benefits | Typical Scenarios |
|---|---|---|---|
| Rear Duals | Aftermarket | More traction | Mud, heavy tillage |
| Track Kits | Aftermarket | Low ground pressure | Wet, soft, sensitive soil |
| Flotation Tires | OEM/Aftermarket | Reduced compaction | Turf, wetlands, soft soil |
Dimensions & Weight
The AGCO ST28A is built as a compact utility tractor with a focus on balance and stability. Its dimensions and weight allow for good maneuverability and simple transport.
| Specification | Value | Notes |
|---|---|---|
| Wheelbase | 65.5 in (166 cm) | |
| Overall Length | 112.8-114.6 in | Dependent on spec, ~291 cm |
| Overall Width (Min Tread) | 49.6-54 in | Depending on wheel setting |
| Height To ROPS / Cab | 79-81.6 in | ROPS: Roll Over Protective Structure |
| Ground Clearance | ~10-13 in | Manufacturer data varies |
| Shipping Weight | 2,205 lbs (1,000 kg) | Bare tractor, minimal fluids |
| Operating Weight (With Fluids) | 2,423-2,425 lbs | With fluids, basic operator |
Wheelbase
Your AGCO ST28A features a wheelbase of 65.5 inches (166 cm). The wheelbase is the distance between the front and rear axles.
This measurement is a major factor in overall stability, especially when operating implements or working on uneven ground. With a 65.5-inch wheelbase, the ST28A maintains a low center of gravity while offering enough length to improve traction and prevent tipping.
This makes it easy to navigate tight spaces often found around small farms, gardens, or landscaping sites. The compact length means you can make tighter turns, which is especially helpful in orchards or when mowing close to obstacles.
The balanced wheelbase helps reduce the risk of tipping when carrying loads, especially with the use of the three-point hitch. For the operator, this results in a safer experience, even on slopes or uneven terrain.
Overall Length
The overall length of the AGCO ST28A ranges between 112.8 inches and 114.6 inches (about 286.7 – 291 cm), depending on exact tire and configuration choices. Length is measured from the front of the tractor (including weights or front hitch, if equipped) to the rear of the three-point hitch.
This moderate length places it in the compact utility tractor class, making it easy to store in smaller sheds or garages. It also helps in transport, allowing you to load the tractor onto standard utility trailers.
A shorter overall length aids in making fast maneuvers and turns in narrow field rows or smaller work areas. If you need to operate in barns, around fences, or in backyard gardens, the size of the ST28A is a benefit.
Overall Width (Minimum Tread)
The overall width of the AGCO ST28A typically measures 49.6 inches (125 cm) at the narrowest tread, and up to 54 inches with certain wheels or tire options. This width is the minimum, designed for moving through tight gates, orchards, or rows.
This width means the tractor can fit down narrow paths and between obstacles. The compact overall width is especially handy when working in greenhouses, inside storage buildings, or between vineyard or orchard rows.
If you need to adjust the tread width for extra stability, you can usually move the wheels outward. At the narrowest setting, the ST28A is one of the more maneuverable compact tractors available, balancing access and stability.
Height To ROPS / Cab
The height to the top of the ROPS (Roll Over Protective Structure) is about 79 inches (200 cm) to 81.6 inches (207 cm). This height includes the protective safety bar that sits behind your seat to protect you if the tractor tips over.
The AGCO ST28A generally does not have a full cab as standard, but some users may add sun canopies or aftermarket covers. The overall height is important for working in barns, garages, or under trees and overhangs.
If your storage has low ceilings, the ROPS can sometimes be folded down. With it in place, you have good safety without sacrificing much clearance.
You still have enough height to give you a clear view over the hood and around the work area. The tractor stays low-profile enough for indoor use and easy loading onto trailers.
Ground Clearance
The ground clearance for the AGCO ST28A is typically between 10 and 13 inches, depending on tires and optional equipment. Ground clearance is measured from the lowest point under the tractor (usually the differential or axle housing) to the ground.
This clearance helps when working on rough fields or uneven ground. It allows you to travel over small obstacles, such as rocks, field debris, or minor ruts, without getting stuck or damaging the tractor’s underside.
For mowing, landscaping, or garden work, this level of ground clearance is usually enough. If you need more clearance for row crop farming or specialty crops, check with your dealer about wheel and tire upgrades.
Shipping Weight
The shipping weight of the AGCO ST28A is 2,205 lbs (1,000 kg). Shipping weight refers to the bare tractor, typically without fluids, operator, or added attachments.
This weight is important when considering transportation on trailers or when lifting for maintenance. The compact weight also makes it possible for many mid-size trailers and trucks to handle transportation without special equipment.
Operating Weight (With Fluids)
The operating weight, including all fluids and a basic operator, is between 2,423 lbs (1,100 kg) and 2,425 lbs. Operating weight can vary depending on tire options, any ballast added, and attached implements.
When fully fueled and topped off with engine oil, coolant, and hydraulic fluid, the tractor is ready for work at this weight. This figure is important for tasks such as weighing down the rear for loader work, or for determining proper trailer and ramp ratings during transport.
If you equip the tractor with front weights, loaded tires, or heavy attachments, the total weight will increase. Always account for extra ballast or implements when calculating safe working or transport capacity.
Fuel & Fluids
For optimal performance and a long service life, you will need to monitor and maintain the AGCO ST28A’s fluid systems closely. The most important fluids are its diesel fuel, engine oil, and hydraulic/transmission oil.
| Fluid Type | Capacity | Importance | Notes |
|---|---|---|---|
| Fuel Tank | 7.1 gallons | Needed for operation | Diesel only |
| DEF Tank | Not applicable | Not required for this model | No DEF system installed |
| Engine Oil | 3.3 quarts | Lubricates and cools engine components | Use recommended oil type/grade |
| Hydraulic/Transmission Oil | 4.2 gallons (combined) | Enables power steering, 3-point, PTO | Use manufacturer recommended type |
Fuel-Tank Capacity
The AGCO ST28A uses a diesel engine, so you will need to fill the tank with clean diesel fuel. The fuel tank holds about 7.1 gallons (27 liters).
This size gives you enough run time for most small property tasks without needing frequent refills. Use fresh, high-quality diesel.
Avoid letting the fuel level drop too low to help prevent air in the lines and possible fuel filter clogging. The fill port is typically found near the left fender or just behind the seat, making it easy to access with standard fuel containers or pumps.
The fuel system includes a replaceable fuel filter, which should be checked or changed as part of regular maintenance. Clean fuel improves engine performance and longevity.
DEF-Tank Capacity (If Applicable)
The AGCO ST28A does not use DEF (Diesel Exhaust Fluid). This system is not required due to the engine’s size and emission standards at the time the tractor was built.
There is no DEF tank to check or fill. You do not need to purchase DEF or monitor any DEF-related components on this tractor.
Operation is less complicated, and the only fluid you add for emissions is clean diesel fuel. This can simplify maintenance and reduce ongoing costs.
Engine Oil Capacity
The engine requires a total of 3.3 quarts (3.1 liters) of oil for full capacity. Oil is essential for reducing engine friction, cooling, and cleaning internal parts.
Always use the oil type and viscosity the manufacturer recommends. For most climates, a 10W-30 diesel-rated engine oil is suitable, but you should verify with your owner’s manual.
Change the oil and the oil filter according to your maintenance schedule, usually every 100 hours or once a year, whichever comes first. Proper oil level and clean oil help ensure reliable starts, quiet running, and reduced engine wear.
To check the oil, use the dipstick on the engine’s side. Always check with the engine off and cooled down.
Never overfill, as this can cause leaks or increased crankcase pressure.
Hydraulic/Transmission Oil Capacity
Hydraulic and transmission fluids are combined in this tractor into one sump. The capacity is 4.2 gallons (about 16 liters).
This fluid powers the hydraulic lift, the PTO (power take-off), and the power steering. Use a Universal Tractor Fluid or a specific hydraulic oil that meets the AGCO specification.
Filling is done at the rear axle, with a sight glass or dipstick to check fluid level. Maintaining the correct level is important for safe and reliable hydraulic function.
Change the hydraulic/transmission oil and filter at intervals set in your operator’s manual (often every 300-400 hours). Always check for leaks around hoses, fittings, and the PTO area.
Low fluid or contamination can cause system failures or unsafe operation.
Electrical System
The electrical system on the AGCO ST28A tractor is designed to provide steady power for starting, operation, and essential functions. Each part of the system is important for safe use and consistent performance.
Ground Type (Negative / Positive)
The AGCO ST28A tractor uses a negative ground electrical system. This is standard for modern tractors and farm equipment.
The negative ground means the negative terminal of the battery is connected directly to the chassis of the tractor. A negative ground setup helps reduce corrosion at battery terminals and makes troubleshooting electrical issues more straightforward.
Most 12-volt electrical equipment and accessories are designed to work with negative ground systems. You should always check before connecting new equipment, but most modern add-ons will be compatible.
In routine maintenance, ensuring a clean and tight negative connection to the chassis will help prevent electrical problems.
Alternator / Charging System
The charging system on the AGCO ST28A is made up of an alternator. The alternator keeps the battery charged during engine operation, powering lights, electric controls, and other accessories.
Unlike older generators, alternators provide more stable voltage and better charging at low engine speeds. You should regularly check the alternator belt for wear or tightness.
A loose or damaged belt can cause undercharging. If you add extra electrical equipment, such as extra lights, confirm that your alternator can handle the extra load.
Alternator problems often show as dim lights or hard starting. If you notice these signs, test the alternator output immediately.
Charging Output (Amps)
The exact charging output in amps for the AGCO ST28A is not always listed in manuals, but most compact tractors with similar engines use alternators with outputs between 30 and 40 amps. This range supports basic tractor functions and allows for a few extra electrical accessories.
Knowing the charging output is important if you plan to add large electrical consumers. For example, extra work lights, cab fans, or powered sprayers will require more amps.
If you need to double-check the output, look at the spec plate on your alternator or contact your dealer. If you consistently run multiple accessories, you may need a higher output alternator to avoid draining the battery.
Battery Voltage
The AGCO ST28A uses a 12-volt battery system. This is the standard voltage for almost all modern tractors and farm equipment.
The 12-volt system powers the starter motor, electrical accessories, and safety systems. You should use a battery that matches this voltage exactly.
Trying to use a 6-volt or 24-volt battery will cause serious electrical issues. For long battery life, keep the terminals clean and check charge levels regularly.
With a 12-volt system, charging is simple. You can use common battery chargers and jump-start equipment if needed.
Battery CCA Rating
CCA stands for Cold Cranking Amps. This is a key number for starting your tractor in cold conditions.
The AGCO ST28A’s recommended CCA rating is generally between 450 and 600 amps, which is typical for tractors of this size. A battery with a CCA rating in this range will provide reliable starting even in cold weather.
If you live in a very cold place, opt for a battery at the higher end of the range. If the CCA is too low, the tractor may struggle to start or keep cranking speed during freezing temperatures.
Always keep the battery fully charged. Replace it if you notice slow cranking, especially as winter approaches.
| Feature | Specification | Notes |
|---|---|---|
| Ground Type | Negative Ground | Most modern tractors use this standard |
| Alternator Type | Alternator | Provides stable voltage during operation |
| Charging Output (Amps) | 30–40 Amps (typical range) | Confirm with actual alternator or dealer specs |
| Battery Voltage | 12 Volts | Standard for compact tractors |
| Battery CCA Rating | 450–600 CCA | Choose higher if operating in very cold climates |
Total Cost Of Ownership Metrics
Understanding the AGCO ST28A tractor’s cost of ownership can help you budget and plan maintenance. Areas like service intervals, maintenance costs, depreciation, and fuel use all factor into total expenses.
| Metric | Details | Typical Values |
|---|---|---|
| Service Interval | Hours or Months Between Servicing | 50, 100, 200, 400, Yearly |
| Annual Maintenance Cost | Parts, Fluids, Labor | $400 – $800 |
| Depreciation Curve | Average Value Lost Per Year | 7%–12% |
| Fuel Consumption @ Rated Load | Liters Per Hour | 3.5 – 4.5 L/hr |
Recommended Service Intervals
For the AGCO ST28A, regular servicing keeps your tractor operating smoothly. It also extends its life.
- Change engine oil and filter every 100 hours or annually, whichever comes first.
- Replace fuel and air filters every 200 hours.
- Inspect and top off hydraulic fluid every 50 hours and change it every 400 hours.
- Grease fittings and check tire pressure at each use or at least every 50 hours.
- Coolant should be checked monthly and changed every two years.
Follow the intervals listed in your owner’s manual. Severe conditions like heavy dust or constant heavy loads can require more frequent maintenance.
Estimated Annual Maintenance Cost
Annual maintenance for the AGCO ST28A includes scheduled services, common repairs, and replacement parts.
On average, you can expect to spend between $400 and $800 each year. This cost covers engine oil, filters, hydraulic fluid, coolant, grease, spark plugs (if applicable), and occasional battery checks or replacements.
If you hire a dealer or mechanic, labor will be the largest part of your expense, often $50–$80 per hour. If you do maintenance yourself, you can save on labor, but the cost of parts and fluids remains.
More extensive repairs, such as clutch or transmission work, may be extra and not included in this range.
Depreciation Curve (% Per Year)
Depreciation impacts a tractor’s resale value over time. For the AGCO ST28A, expect an average annual depreciation of 7% to 12% after the first year.
If you bought a new unit for $17,000, its value after five years might be around $10,000 to $12,000, depending on condition, hours, and market demand.
Proper maintenance and lower usage can help slow depreciation. Neglect, accident damage, or using your tractor in harsh conditions will speed it up.
Always keep records of maintenance to support your resale value.
Fuel Consumption @ Rated Load (L Hr⁻¹)
At full power, the AGCO ST28A’s 28 hp engine consumes about 3.5 to 4.5 liters of diesel fuel per hour.
Actual fuel usage varies depending on the job.
Lighter loads or idling use less, while mowing thick grass, tilling, or using a loader attachment will increase consumption.
Keep the air filter clean and properly maintain your tractor to ensure the engine runs efficiently.
Use clean, quality diesel to avoid engine issues and reduce long-term fuel expenses.