# MF40/40B Hydraulic issues



## MFinWA (Dec 19, 2016)

Just put this old girl back together. Only showing 500 P.S.I on gage. yes tried more than 1 gage. Old style control valve, Just rebuilt. Any suggestions? Hey Shona are u out there?


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## RC Wells (Dec 26, 2008)

If you removed the hydraulic transfer cap to put oil in it is common to not place the Standpipe back in the pump correctly. 

Set the the three point draft in the up position, and the lift control lever in the transport position, remove the 3/8 " national pipe thread plug on the side of the lift cover (right front) above the transmission dipstick. 

IMPORTANT PULL THE ENGINE STOP OUT SO THE ENGINE WONT RUN and crank the engine while observing that port you just opened. Oil should come out of the port. 

If oil does not come out, pull the key so you do not get an accidental bump on the starter, drop the lift arms, remove the transfer cap that is held on by two setscrews (located above the plug you removed). Once the cap is removed you should see the hydraulic standpipe exposed about 3/8 inch. If you see nothing but a hole the standpipe has fallen inside.

If that is the case remove the right side plate (one with the transmission dipstick). Insert your hand in the access port you just opened, and reach forward. You will feel the pipe that is approximately a foot long. Line it up with the hole in the cover at the top, pull it out and and replace the O rings. To reinstall the standpipe it is necessary to reach inside and locate the hole in the pump where the pipe inserts, line the pipe up with the pump, and give the upper end a light tap to press the lower O ring into the pump. Install a new O ring on the underside of the cap, reinstall the cap then button everything up and you should have pressure.

If you did not install new O rings on that pipe when you installed the pump the same process will be followed to pull the standpipe and install new O rings. Just will not need to fish for the pipe, but will need to use your finger in the pump port to locate and fish out any old or broken O ring.


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## MFinWA (Dec 19, 2016)

The stand pipe is in place. All new O-rings. If the pipe was dislodged or leaking It would not hold position. Believe me I went to change out the gauge I was using and had the lift arms up a couple of inches and got a bath. New lift cylinder and piston, about 75% of the linkages, levers etc. are new. I rebuilt the pump with new chambers, and slide valve. I overhauled the pressure control valve as I could not find a 1661427M91 mounting block to go to the cartridge style relief. The rear body of the pump is an early MKIII without the provisions to direct mount the other style. I am following the 40B service manual as this system is not in the 40 service manual. I rigged the cover with all of the special tooling. That turned out good. I think it may be the pressure control valve is sticking or the secondary relief is stuck open. Without pressure control it should be staying closed. I am testing with the response control in fast, draft lever fully up and position control in constant pumping. little to no change in pressure when trying to adjust.


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