Kubota MX5800 400-Hour Maintenance Guide

Performing your own 400-hour service is a great way to get to know your Kubota MX5800. Pro Tip: Before you begin, ensure your brush guard is moved all the way forward. The hood on the MX series swings up high, and you can easily scratch or dent it against the guard if it isn't cleared first.

What’s Included in the 400-Hour Service

• Engine oil and oil filter
• Outer air filter
• Spin-on fuel filter
• Fuel sediment bowl screen
• Hydraulic / hydrostatic transmission filters (both)
• Complete hydraulic fluid change
• Greasing all serviceable fittings
• General inspection

Tools & Supplies Needed

• 24 mm socket or wrench
• 19 mm socket or wrench (preferably 6-point)
• 14 mm socket or wrench
• Oil filter wrench (3½"–3⅞")
• Large drain pan (12-gallon minimum capacity)
• Brake cleaner
• Clean rags
• Safety glasses
• Engine oil (7.4 quarts)
• Hydraulic fluid (approximately 11.4–12 gallons)

Draining the Hydraulic / Transmission Fluid

Drain Points

• Main transmission drain plug
• Two axle drain bolts (low points)

Procedure

1. Position a large drain pan under the tractor.
2. Remove the main transmission drain plug first.
3. Remove the two axle drain bolts to fully drain trapped fluid.
4. Allow all fluid to drain completely.

Drain Plug Washer Orientation

The drain plug washer includes a rubber O-ring and paint on one side. Reinstall the washer paint-side down, matching the original orientation. Tighten snugly with a small bump—do not overtighten.

Reinstall the axle drain bolts once drained and snug them securely.

Replacing Hydraulic & Transmission Filters

• Factory-installed filters may be extremely tight.
• Loosen filters slowly and allow them to drip before removal.
• Inspect and clean the filter mating surface before installing new filters.
• Pre-lube all O-rings with clean oil.

Magnet Note

One hydraulic filter includes a magnet to capture metal particles. The replacement filter comes with its own magnet and should be installed as supplied.

Filters may be tightened snugly using a wrench to prevent backing off, especially if you will be the next person servicing the tractor.

Refilling Hydraulic Fluid

Refill the hydraulic system through the red fill cap. A cut milk jug can be used as a makeshift funnel to improve access.

• Expected capacity: approximately 12 gallons
• Verify level using the hydraulic sight glass

Kubota Super UDT2 or an approved equivalent hydraulic fluid is recommended.

Engine Oil & Filter Change

Draining Engine Oil

The engine oil pan contains two drain plugs due to the front driveshaft splitting the pan. Both plugs must be removed for a complete drain.

1. Remove both drain plugs and allow oil to drain completely.
2. Reuse copper washers if undamaged.
3. Reinstall drain plugs snugly.

Replacing the Oil Filter

• Use a filter cup to reduce mess during removal.
• Pre-lube the new filter gasket with clean oil.
• Install and tighten snugly.

Refilling Engine Oil

• Capacity: 7.4 quarts
• Add approximately 7 quarts initially
• Start engine, shut down, and recheck level
• Final level should be near the upper hash mark on the dipstick

Fuel System Service

Fuel Screen (Sediment Bowl)

1. Turn the fuel shutoff to OFF.
2. Remove the sediment bowl and place a drain pan underneath.
3. Clean debris using brake cleaner.
4. Install the new screen, spring, and float.
5. Reinstall and tighten lightly.
6. Turn the fuel shutoff back ON.

Spin-On Fuel Filter

• Use a filter cup to catch diesel fuel.
• Lightly oil the new filter O-ring.
• Install and tighten snugly.

Fuel System Priming

Cycle the key to activate the electric fuel pump. Allow it to run for approximately 15 seconds, then repeat once more before starting the engine.

Air Filter Replacement

1. Release the three clips on the air filter housing.
2. Remove the outer air filter.
3. Wipe dust and debris from the housing.
4. Install the new outer filter over the inner filter.
5. Ensure the filter is fully seated.
6. Position the dust boot at the bottom.
7. Reinstall the housing cover and secure the clips.

Greasing the Tractor

Apply grease to all serviceable fittings, including:

• Front axle pivot points (front and rear)
• Both sides of the axle
• Loader grease points (if equipped)

Final Inspection

• Verify all drain plugs and filters are tight
• Confirm all fluid levels are correct
• Check for leaks
• Reinstall shields and panels
• Clean residual oil and debris from service areas