Hydraulic Filter Service


Yanmar uses 1 reservoir for both the hydraulic oil and the transmission oil. This oil is a Hydraulic Transmission oil. Never use a simple Hydraulic oil.

The hydraulic pump on all yanmar tractors is very simple. It is basically two gears running together at high speeds to move the oil. These gears must have extremely tight tolerences in order for this to work. Because of these tight tolerences, and dirt or debris will almost always destroy a pump.

Because of this, it is important that your oil be clean and your filter or screen be serviced periodically. Not all Yanmar tractors have hydraulic filters. In fact only the '20 series, '02 series, some of the F and Fx series gray market, and some of the US versions have a spin on filter. Most have small tubular screens inside the transmission housing that filter the oil.

If your tractor has a spin on filter, replacement is a breeze.

1 - Be sure that you have a replacement filter on hand. These are not filters that you will find at a local parts store. Please check our sponsors for a replacement hydraulic filters.

2 - Using a filter wrench or channel lock plyers, remove the oil filter. As the oil is draining out of the filter housing, remove the drain plug. This is located just below the rear axles. There may be two or more plugs that you will need to remove in order to get all of the oil drained. Use a large drain pan as it may hold many gallons.

3- If your tractor has the screen type filter, after the oil has drained, locate the screen. The screen will always be in the transmission housing. It will usually be on the directly on the opposite side of the large hydraulic suction line that goes into the right (sitting on the seat) side of the transmission. You will need to remove a 2-4 bolt plate that holds this filter in. The filter may also be directly behind the large suction line. To remove this filter you will need to remove the rubber hose connection thatcouples the two sections of steel hyd line together. Then remove the 3-4 bolt plate where the line goes into the transmission. The screen will be behind that plate. If the screen is in none of these places, it will be behind a 2-3 bolt plate at the very botton of the transmission. Refer to your parts manual or operation manual for exact location.

4 - Clean the screen with a carburator cleaner or fresh diesel.

5 - Re-install screen and cover. Re-fill with the correct amount of Hydraulic Transmission oil. Never use a simple Hydraulic oil. Check periodically with the dipstick or check your Yanmar operation manual for your tractor.

6 - Start tractor and check for leaks.