How to Change a Bobcat Fuel Filter Step by Step

Changing the fuel filter on a Bobcat involves draining the old filter, swapping in a new one that matches your model's specifications, and priming the fuel system to remove trapped air. Bobcat recommends fuel filter replacement every 500 hours or annually, whichever comes first. The most critical step that many owners skip is priming the fuel system after installation, which prevents hard starts and air lock issues.

The Essentials

• When to change: Every 500 hours or annually, whichever comes first
• Tools needed: Filter wrench, drain pan, clean rags, combination wrenches, clean diesel for pre-filling
• Time required: 20-45 minutes including priming
• Common mistakes: Skipping the priming step, not pre-filling the new filter, reusing the old gasket

Why Is the Fuel Filter Important on a Bobcat?

The fuel filter is the last line of defense between your fuel tank and the engine's fuel injection system. Diesel fuel can contain water, sediment, rust particles, and microbial growth, all of which damage the precision components in modern fuel injectors.

According to Bobcat's maintenance documentation, fuel injectors operate with tolerances measured in thousandths of an inch. Contaminants that pass through a failed or clogged fuel filter can score injector nozzles, cause uneven spray patterns, and lead to incomplete combustion. The result is lost power, increased fuel consumption, and expensive injector replacement.

Some Bobcat models use a dual-stage filtration system with a primary filter (water separator) and a secondary fine filter. Both stages work together to remove water and particulates before fuel reaches the injection pump.

How Often Should I Change My Bobcat Fuel Filter?

Bobcat's recommended fuel filter change interval is every 500 hours of operation or once per year, whichever comes first. This interval applies to both the primary and secondary fuel filters on models with dual-stage filtration.

Factors that may require more frequent changes:

• Contaminated fuel supply: Fuel stored in older tanks or portable containers is more likely to contain water and sediment
• Infrequent use: Machines that sit for extended periods can develop condensation in the fuel tank, leading to water in the fuel
• Extreme temperatures: Cold weather can cause wax crystals in diesel fuel that clog filters faster
• High-dust environments: Dust entering the fuel system through the filler cap accumulates in the filter

Our parts specialists recommend combining your fuel filter change with the engine oil and air filter changes at the 500-hour service interval. This keeps all filters on the same schedule and minimizes downtime.

What Are Signs That My Fuel Filter Needs Changing?

A clogging fuel filter restricts fuel flow to the engine. The symptoms are progressive and often mistaken for other problems:

• Loss of power under load: The engine runs fine at idle but bogs down when lifting, pushing, or driving uphill
• Hard starting: The engine cranks longer than usual before firing, especially after sitting overnight
• Rough idle or surging: Inconsistent fuel delivery causes the engine to hunt or surge at idle speed
• Engine stalling: The engine quits under load or at low RPM when fuel demand exceeds the restricted flow rate
• Black exhaust smoke: Restricted fuel flow causes incomplete combustion and visible smoke

If your Bobcat shows these symptoms and you are near or past the 500-hour interval, the fuel filter should be the first thing you check.

Where Is the Fuel Filter Located on a Bobcat?

Fuel filter location varies by model, but most Bobcat skid steer loaders and compact track loaders mount the fuel filter in the engine compartment near the fuel injection pump. Access is typically through the rear engine compartment door.

Common locations:

• Skid steers (S-series): Right side of engine compartment, often near the top of the engine between the air filter housing and the fuel injection pump
• Compact track loaders (T-series): Similar to skid steers, accessible through the rear door
• Mini excavators (E-series): Under a side access panel, typically near the fuel tank and injection pump

On models with dual filtration, the primary filter (water separator) is usually mounted lower and may have a drain valve at the bottom. The secondary filter sits between the primary and the injection pump. Consult your operator's manual for the exact location on your model.

What Tools and Supplies Do I Need?

Fuel filter replacement requires basic hand tools and a few supplies to do the job cleanly:

• Filter wrench (sized for your fuel filter canister)
• Drain pan to catch fuel spillage
• Clean rags for wiping up drips
• Combination wrenches for any bracket or mounting hardware
• Clean diesel fuel for pre-filling the new filter
• New fuel filter gasket (included with most replacement filters)
• Safety glasses

Safety note: Diesel fuel is flammable. Work in a well-ventilated area away from open flames, sparks, and heat sources. Have a fire extinguisher accessible. Do not smoke while working on the fuel system.

How Do I Change the Fuel Filter Step by Step?

Follow these steps for a clean fuel filter change. The process applies to most Bobcat spin-on style fuel filters. Cartridge-style filters follow a similar sequence but involve opening a filter housing instead of unscrewing a canister.

1. Shut down the engine: Turn off the machine and allow the engine to cool. Disconnect the battery as an extra precaution
2. Clean the area: Wipe down the filter housing and surrounding area to prevent dirt from falling into the fuel system during the change
3. Position the drain pan: Place it directly under the filter to catch fuel that drains when the filter is removed
4. Remove the old filter: Use the filter wrench to unscrew the old filter. Turn counterclockwise. Allow the remaining fuel to drain into the pan
5. Clean the mounting surface: Wipe the filter base on the engine to remove the old gasket material and any debris. Inspect the surface for damage
6. Pre-fill the new filter: Fill the new filter with clean diesel fuel. This reduces the amount of air that enters the fuel system and shortens the priming process
7. Install the new filter: Apply a thin film of clean diesel to the new gasket. Thread the filter on by hand until the gasket contacts the base. Tighten an additional 1/2 to 3/4 turn by hand. Do not overtighten
8. Prime the fuel system: Use the manual primer pump (located near the fuel filter housing on most Bobcat models) to pump fuel through the new filter and purge air from the lines. Pump until you feel firm resistance
9. Start the engine: The engine may crank longer than usual on the first start. This is normal. If it does not start within 15 seconds of cranking, wait 30 seconds and try again. Repeat the priming step if needed
10. Check for leaks: With the engine running, inspect the new filter and all fuel connections for leaks. Tighten if necessary

Do I Need to Prime the Fuel System After Changing the Filter?

Yes. Priming is essential and is the most commonly skipped step during a fuel filter change. When you remove the old filter, air enters the fuel lines between the tank and the injection pump. If that air is not purged, the engine will not start or will run roughly.

Most Bobcat machines have a manual primer pump, which is a small rubber bulb or lever located near the fuel filter housing. The priming process involves:

1. Locate the primer pump near the fuel filter housing
2. Pump the primer repeatedly until you feel firm, consistent resistance
3. On some models, you may need to crack open the bleed screw on the injection pump while priming to release trapped air. Tighten the bleed screw once fuel (not air bubbles) flows out

According to Bobcat's service manual, failure to properly prime the fuel system after a filter change can cause air lock in the fuel injection pump. In severe cases, this can damage the injection pump and require professional service to resolve.

What Are Common Bobcat Fuel Filter Part Numbers?

Bobcat fuel filter numbers vary by engine platform and model generation. Here are commonly referenced OEM numbers from our catalog data:

OEM Part Number	Filter Type	Common Models
6667352	Fuel filter	753, 763, 773, 863 (Kubota engine models)
7012350	Fuel filter	S550, S570, S590, T550, T590
7253331	Fuel filter/water separator	S650, S770, T650, T770, T870
7012314	Fuel filter	E32, E35, E42, E50, E55 (Yanmar engine)

Always verify the correct part number for your specific model and serial number. Browse our Bobcat parts collection to search by OEM number or model.

Can I Use an Aftermarket Fuel Filter on My Bobcat?

Aftermarket fuel filters are manufactured to meet OEM filtration standards, including micron rating, water separation capacity, and flow rate. They use the same filter media quality and gasket materials as the original.

The key specifications to verify when cross-referencing an aftermarket fuel filter:

• Micron rating (must match OEM specification for your injection system type)
• Thread size and gasket diameter
• Water separation capability (for primary/water separator filters)
• Flow direction (directional filters have an arrow indicating correct installation)

Aftermarket fuel filters typically cost 20-60% less than dealer-sourced OEM filters. For owners on a regular maintenance schedule, the savings per filter add up over the life of the machine. Browse our Bobcat skid steer parts for fuel filters listed by model.

What Mistakes Should I Avoid When Changing the Fuel Filter?

These are the most common mistakes that cause problems during or after a fuel filter change:

• Skipping the prime: Not priming the fuel system introduces air into the injection pump. The engine will not start or will stall repeatedly
• Not pre-filling the new filter: Installing a dry filter means the primer pump has to move fuel through the entire empty canister plus the lines. Pre-filling shortens this process significantly
• Reusing the old gasket: The rubber gasket compresses during installation and will not seal properly a second time. Always use the new gasket included with the replacement filter
• Installing the filter backwards: Directional fuel filters have an arrow indicating the correct flow direction. Installing a filter backwards restricts fuel flow and can damage the injection system
• Overtightening: Spin-on filters should be hand-tightened only (gasket contact plus 1/2 to 3/4 turn). Using a filter wrench to tighten can crush the gasket and make the filter difficult to remove at the next change
• Not cleaning the mounting surface: Old gasket material left on the base creates a poor seal with the new filter, leading to fuel leaks
• Cross-threading: Starting the filter crooked on the threads damages both the filter and the housing. Always start threading by hand before using any tools

Frequently Asked Questions

How do I bleed air from my Bobcat fuel system after a filter change?

Use the manual primer pump near the fuel filter housing. Pump until you feel firm resistance. On some models, you may need to open the bleed screw on the injection pump while priming, then close it once bubble-free fuel appears.

Can a clogged fuel filter cause my Bobcat to lose power?

Yes. A restricted fuel filter limits the volume of fuel reaching the injection system. The engine may idle normally but lose power under load when fuel demand increases beyond what the clogged filter can deliver.

Should I change the fuel filter and oil filter at the same time?

Combining fuel, oil, and air filter changes into a single maintenance session at the 500-hour interval is efficient and keeps all filters on the same replacement schedule. Bobcat's maintenance schedule supports this approach.

What happens if I install the fuel filter backwards?

A reversed directional filter restricts fuel flow because the media is designed to filter in one direction. Symptoms include hard starting, loss of power, and potential damage to the fuel injection pump from fuel starvation.

How do I find the right fuel filter for my Bobcat model?

Check your operator's manual for the OEM part number, or look at the number stamped on your current filter. Search that number on our Bobcat parts page. Contact sales@partsonline.com with your model and serial number if you need help.

Is it safe to reuse a fuel filter gasket?

No. The rubber gasket compresses during the initial installation and will not form a proper seal when reused. Always install the new gasket that comes with the replacement filter to prevent fuel leaks.

Why does my Bobcat crank but not start after a fuel filter change?

Air trapped in the fuel lines is the most likely cause. Repeat the priming process until you feel firm, consistent resistance from the primer pump. If the engine still will not start after thorough priming, check for loose fuel line connections that may be allowing air to enter the system.

Can water in the fuel damage my Bobcat engine?

Yes. Water in diesel fuel causes corrosion in the injection pump and injectors, and can cause injector tips to crack from thermal shock during combustion. If your machine has a water separator filter with a drain valve, drain it regularly to remove accumulated water.