Squeal and 3pt raises when cranking

[jonree]

I posted this in the Mitsubishi forum but thought I might get a general hydraulics answer here. Bought a Mitsubishi D1800 at an auction, 3pt was not working, no squeal and tractor ran fine but felt like no resistance at the control lever, but I went ahead and replaced the hydraulic oil and cleaned the filter since it was cloudy. Didn't have any resistance and pressure at the control valve so I replaced the pump.

Now the 3pt lifts upon cranking, has pressure at the control valve and a high pitched squeal that sounds like its coming from the suction pipe. The only way to lower the 3pt is unscrewing the control valve until oil is released. The lock lever will not keep it from raising and won't help in lowering.

Any thoughts would be appreciated.

Thanks!

 

[Sysop]

Sounds like something is plumbed backwards at the valve or the valve is failed. With the lever fully forward, the lift should stay at the lowest position. The lock on the lever isn't to keep it from raising, it is to keep you from lowering an implement too far down.

 

[jonree]

Sounds like something is plumbed backwards at the valve or the valve is failed. With the lever fully forward, the lift should stay at the lowest position. The lock on the lever isn't to keep it from raising, it is to keep you from lowering an implement too far down.

Thanks for the reply! Do you think if the lift lever linkage is broken in the up position it could cause this? Thanks!