Bobcat Fluid Capacities and Service Specs by Model

Fluid capacities vary by Bobcat model and by serial range, and published sources frequently disagree with each other. A Bobcat S250 fuel tank is listed at 25 gallons in official specifications, while other guides put it between 23 and 27. That spread is why the machine's own manual, matched to your serial, is the only figure worth trusting mid job.

The Essentials

• Capacities vary by serial range, not just by model
• Published sources disagree, sometimes by several gallons
• The authority is the operator manual for your serial
• Socket sizes are not published in most operator manuals at all
• Expect air in the system after a hydraulic service
• Filters and O-rings go together, and the O-rings are what get forgotten

What Fluids Does a Bobcat Skid Steer Take?

Five separate systems hold fluid, and each has its own capacity, its own specification and its own service interval.

• Engine oil, with a filter change at the same interval
• Hydraulic and hydrostatic fluid, which on most Bobcat loaders is a shared reservoir serving both
• Coolant
• Fuel, which is capacity rather than a service item
• Final drive or chaincase oil, which is frequently forgotten entirely

The chaincase is the one owners miss most often. It is a sealed system with a long interval, so it never comes up in routine servicing, and then it does not get checked for a decade.

How Much Fuel Does Each Model Hold?

Fuel capacity is the most consistently published of the capacity figures, and it is a reasonable proxy for machine size class. The figures below are published specifications for the models concerned.

Model	Published fuel capacity
Bobcat 463	6.5 gal (24.6 L)
Bobcat 753	14 gal (53 L)
Bobcat S250	25 gal (94.6 L)
Bobcat 863	25 gal
Bobcat T300	30 gal (113.6 L)

Treat these as starting points rather than final answers. On the S250, official specifications give 25 gallons while other published guides list anywhere from 23 to 27, and that kind of spread appears across the range. Serial variations, tank changes mid production and simple copying errors between sources all contribute.

As a rough guide to consumption, a machine of the S250 class working hard at digging uses in the region of 3.2 gallons per hour. That figure moves considerably with the work, so it is useful for planning a day rather than for calculating anything precisely.

How Much Hydraulic Fluid and Coolant Does a Bobcat Hold?

These are the capacities that matter mid service, and they are the ones published least consistently.

Where figures are available they are model specific rather than transferable. The Bobcat 463, as an example of the compact end of the range, is published at 5.3 quarts hydraulic reservoir and 6.0 quarts coolant. Those numbers tell you nothing about a 753 or an S250, which are much larger machines.

There is an important distinction that catches people out on hydraulic systems:

• Reservoir capacity is what the tank holds
• System capacity is the total including lines, cylinders, pump and motors
• Refill quantity after a service is neither of those, because a drain never removes everything

A manual quoting system capacity will send you to buy more fluid than a routine filter change actually consumes. Read which figure is being quoted before ordering fluid, and expect to top up to a level rather than measure in a fixed amount.

Why Does the Manual Not Always Give a Capacity?

This is the honest heart of the problem, and it is worth stating plainly rather than pretending otherwise.

Operator manuals are written around procedures, and many procedures specify a level rather than a volume. The instruction is to fill to a sight glass or dipstick mark, not to add a stated number of quarts. That is correct engineering guidance, because how much a machine actually takes depends on how thoroughly it drained and what remains in the lines.

It is also genuinely unhelpful when you are standing at a parts counter deciding how much fluid to buy.

Where a capacity is genuinely not published for your model and serial, the practical approach is:

• Buy to the nearest larger quantity and keep the remainder for topping up
• Measure what comes out during the drain, which tells you what goes back in more accurately than any published figure
• Fill to the level indicator, which is what the manual actually asks for
• Record what your machine took for next time. That number is worth more to you than any chart

The last point is the one that saves the most time. A capacity written on the inside of the engine door in permanent marker after the first service ends the question permanently for that machine.

What Socket and Wrench Sizes Do You Need?

Tool sizes are the specification least likely to appear in any manual, which is exactly why the question dominates comment sections under service videos.

We are not going to publish a socket size chart, and the reason matters. Fastener sizes vary between models, between serial ranges within a model, and between original and previously replaced components. A chart that is right for one machine is wrong for another, and a wrong socket size sends someone to the store for a tool they did not need while the machine sits open.

What works instead:

• Measure before you start. Check the fastener with the machine cold and intact rather than discovering the size once it is half apart
• Do not trust a video. Owners regularly report that the drain plug on their machine was a different type entirely from the one shown in a walkthrough, including plain bolts where a video showed a hex key fitting
• Expect metric, but verify rather than assume, particularly on machines that have been repaired before
• Have a filter wrench sized to the canister, since spin on filters seize with age and heat

Seized canister filters are worth anticipating on any machine with years on it. A strap wrench and penetrating oil applied the day before turns a stuck filter from a wasted afternoon into a normal service step.

Where Are the Fill and Drain Points?

Locations vary by model and by generation, and the operator manual for your serial is the reference. What holds generally across the range:

• Hydraulic fill is normally accessed through the rear engine compartment, with a sight glass or dipstick nearby for level
• Engine oil fill and dipstick are on the engine itself, reached through the rear door
• Drains sit at the lowest point of each system and are often reached from underneath
• Chaincase drain and fill plugs are on the machine sides, low down, and are easy to mistake for structural fasteners

One recurring frustration deserves naming: on some machines the hydraulic fill point is genuinely hard to find, and owners end up filling through a dipstick tube because they cannot locate a cap. Before improvising, check the manual for your specific model, because filling through the wrong opening can bypass a filter screen.

How Do You Get the Air Out After a Hydraulic Service?

Air in the system after a hydraulic filter or fluid change is normal, not a sign that something went wrong. Knowing that in advance saves a lot of worry the first time it happens.

What it looks like:

• Foamy or milky looking fluid in the sight glass immediately after filling
• Noisy or erratic operation on first start
• Slow or jerky cylinder movement until the air works through

The general approach is to start the machine and let it idle without load, then cycle each function slowly and repeatedly through its full travel, checking the fluid level again once the air has come out of suspension. On hydrostatic drive machines, follow the manual procedure for your model rather than improvising, since some require a specific sequence.

If milky fluid persists after the air has had time to clear, that is a different problem. Water contamination looks similar and does not resolve with cycling, and it needs diagnosing rather than running.

Consult a certified mechanic for hydraulic system work if the machine does not settle after a normal purge.

Which Filters Go With Each Fluid Change?

Each fluid change has a filter that goes with it, and the O-rings that go with the filter are what get left out of the order.

Ordering filters with their seals included avoids the most common mid service stop. A Hydraulic Oil Filter with O-Rings replacing Bobcat 7414582 is exactly the kind of part worth buying as a set rather than discovering the old O-ring has flattened once the housing is open.

Other hydraulic elements commonly needed include the Hydraulic Oil Tank Filter replacing Bobcat 7002734 and the Hydraulic Oil Filter replacing Bobcat 6692337. Which applies to your machine depends on model and serial, so match against the OEM number rather than the model badge.

A point worth making about the tank filter specifically: many machines have more than one hydraulic filter, and the second one is inside the reservoir where it is easy to overlook. Changing the spin on element and leaving a clogged in tank screen produces a machine that is still slow after a service, which is a common and frustrating outcome. Our guide on when to replace your Bobcat hydraulic filter covers where each one sits.

How Do You Confirm the Right Spec for Your Machine?

Every specification on this page is model and serial dependent, so the confirmation route matters more than any individual figure.

1. Record the machine serial and the engine serial before looking anything up
2. Use the operator manual for that serial range, not a manual for the model generally
3. Cross check against a second source where a figure looks unusual, since published sources disagree
4. Measure the drain when in doubt, because your machine is the most accurate reference available
5. Write down what it actually took and keep that record with the machine

Customers are responsible for verifying fitment and specification before ordering. If you have a serial number and are unsure which filter or how many O-rings a service needs, send it to sales@partsonline.com and our team will match the parts to your build. Browse the range at Hydraulic Filters or across Bobcat Parts.

Frequently Asked Questions

How much hydraulic fluid does a Bobcat hold?

It varies by model and serial range, and published figures often disagree. The compact Bobcat 463 is listed at 5.3 quarts of hydraulic reservoir capacity, while larger machines hold considerably more. Use the operator manual for your serial, and fill to the sight glass rather than to a fixed volume.

What is the fuel capacity of a Bobcat S250?

Official specifications list 25 gallons (94.6 litres), though other published guides put it between 23 and 27 gallons. That variation is typical across the range and is why the manual for your serial is the figure to work from.

Why does my Bobcat manual not list a fluid capacity?

Many procedures specify filling to a level indicator rather than adding a stated volume, because how much a machine takes depends on how completely it drained. It is correct guidance and unhelpful at a parts counter. Measure your drain and record what it took.

What socket size do I need for a Bobcat hydraulic filter or drain plug?

Sizes vary by model, serial range and whether components have been replaced previously, so no single chart is reliable. Measure the fastener before starting work, and do not assume a size shown in a video matches your machine.

Is it normal to have air in the hydraulic system after a filter change?

Yes. Foamy fluid and noisy or erratic operation on first start are expected. Idle without load, cycle each function slowly through full travel, then recheck the level once the air has come out of suspension.

How long will a skid steer run on a tank of fuel?

Depends on machine size and how hard it is working. A machine of the S250 class doing heavy digging uses in the region of 3.2 gallons per hour, so a 25 gallon tank covers a working day with margin. Lighter work extends that considerably.

Does a Bobcat have more than one hydraulic filter?

Many do. Alongside the spin on element there is frequently a screen or filter inside the reservoir. Changing only the spin on filter and leaving a clogged in tank element is a common reason a machine is still slow after a service.

Should I order O-rings with a hydraulic filter?

Yes. Old O-rings flatten and harden, and reusing one is a common cause of a leak created during the service itself. Filters supplied with their seals avoid a mid job stop.