Quick Summary
This guide walks you through a full service on the Case 75C utility tractor, covering every major maintenance point: engine oil and filter, dual hydraulic filters, two fuel filters, and inner/outer air filters. You'll also learn where to find the hydraulic drain, fill, and dipstick locations, how to use the vacuum trick to avoid losing fluid during filter changes, and how to inspect your O-rings and drain plugs. Key fluid capacity: the hydraulic sump holds just over 10 gallons, and the engine takes approximately 9 quarts of engine oil. This also applies to the New Holland Powerstar 75.
Hood Access & Filter Layout
Before you start, you'll need to open the hood and remove the side shield to access the service area. The hood has a small button you push to lift it up. The side shield is secured with a 13 mm nut — remove it, then pull out the pin holding the panel and lift it free.
Once inside, here's where everything lives: the air cleaner housing is accessible via four spring clips on the left side. The coolant reservoir sits on top of the engine — check the level while you're in there. There are also radiator inlet screens you should inspect and clean of any debris. The two fuel filters are grouped together in the center of the engine bay, with the engine oil filter tucked behind them. The large canister suction filter for the hydraulic system is a spin-on type, and a second spin-on hydraulic screen filter is located underneath the cab next to the loader valve on the right side.
Draining the Hydraulic System
The hydraulic drain plug is at the rear axle — it's the lowest point in the system and the correct place to do a full drain. You'll need a 17 mm hex Allen socket to remove it. ⚠ Make sure you have a drain pan that holds more than 10 gallons — the hydraulic sump holds just over that amount.
Inspect the drain plug O-ring when you pull it. If it has taken on a cone shape rather than a round cross-section, replace it with a new O-ring and drain plug before reinstalling. The plug does not need to be cranked down hard — snug is sufficient. Overtightening can damage the O-ring and cause a slow leak.
Changing the Hydraulic Filters
The Case 75C has two hydraulic filters. The first is a large spin-on canister accessible from the engine bay. Use a filter wrench to break it loose. Messick's recommends draining all hydraulic fluid before swapping this filter to avoid a big mess — don't skip this step.
The second hydraulic filter is a metal housing with a replaceable stainless screen inside. It's located underneath the cab next to the loader valve and requires a 32 mm wrench to remove. The housing itself is reused — only the internal screen is replaced. Once the new screen is seated, reinstall the housing snug. Lube the O-ring before threading it back on.
Pro tip: After filling the system with fresh fluid, use a vacuum on the fill tube to pull fluid through the new filters without pumping. Tape the vacuum hose for a good seal, and keep the vacuum unit positioned higher than the fill point to prevent fluid from being sucked up into it.
Engine Oil & Filter Change
The Case 75C engine oil pan has two drain plugs — one accessible on the right side of the tractor, and a second located right next to the hydraulic filter position. The second plug uses a 12 mm hex socket. Draining both gives you a more complete oil change, though the second drain yields a relatively small volume.
The engine oil filter is tucked behind the fuel filters, so you'll need to remove the fuel filter assembly first to get a wrench on it. Disconnect the water separator sensor, squeeze the clip to release it, and move it out of the way. Always lube the new filter gasket with fresh oil before installing. Tighten by hand plus a quarter to half turn — do not overtighten. The engine holds approximately 9 quarts of engine oil. Fill, then start the engine to prime the new filter — recheck your level and top off as needed.
Fuel Filter Replacement
There are two inline fuel filters on the Case 75C, grouped together in the engine bay. The fuel cup and strainer (identifiable by the green dot, located further back) does not need to be replaced at every service interval and was left in place during this service.
When installing the new fuel filters, lube the filter gaskets and hand-tighten. After installation, prime the filters by pumping until fuel flows through — you should see fluid coming out before you consider the job done. Reconnect the water separator sensor and clip it securely back into place.
Air Filter Service
The air filter housing is on the side of the engine and is held by four spring clips. Flip the clips up and the housing drops away. Inside you'll find both an outer filter and an inner filter — replace both at service time. Pull the outer filter straight out, then grab the inner filter by its two rings and pull it free.
While you have the housing off, inspect the inside for dirt buildup and squeeze the dust ejector boot to clear any accumulated debris — this is easy to overlook. When installing the new outer filter, push it firmly until it sits flush with the seating lip. Reinstall the housing and snap all four clips closed securely.
Refilling & Final Checks
The hydraulic fill port and dipstick are located together — clean the area thoroughly before removing the cap to prevent contamination. Pull the dipstick out while filling so your funnel drains freely without air bubbling back at you. Start with approximately 10 gallons and check the dipstick to see where you land, then top off as needed.
After completing all fluid fills, start the tractor to circulate the new engine oil and hydraulic fluid. Recheck all levels and inspect around each filter and drain plug for any weeping or leaks. A quick walk-around at this stage can save you from discovering a loose filter the hard way.
Frequently Asked Questions
Do I really need to drain all the hydraulic fluid just to change the filter?
It's strongly recommended on the Case 75C. The hydraulic filter is not positioned at the bottom of the system, so removing it with fluid still in the sump will cause a significant spill. Draining first also gives you the benefit of getting fresh fluid throughout the entire system. Since the sump holds over 10 gallons, the mess from not draining is substantial.
How do I know when the inner air filter needs to be replaced?
On most Case tractors, the inner (secondary) air filter should be replaced every second or third time you change the outer filter — not every service. However, always pull and visually inspect it when you have the housing open. If it shows visible dirt penetration, damage to the end caps, or any tears, replace it immediately regardless of interval. Never attempt to clean the inner filter by blowing it out — it should only ever be replaced.
What type of hydraulic fluid does the Case 75C use?
The Case 75C requires Case Akcela Hy-Tran Ultra universal trans-hydraulic fluid, or an approved equivalent. Using the wrong fluid can damage seals and reduce the performance of the hydraulic system and transmission. Always confirm the correct spec in your operator's manual or contact Messick's parts team if you're unsure which fluid to use for your specific machine configuration.
