Weak hydraulics

[Lanny Collins]

Friend has McCormick GX50 tractor with weak hydraulics. Will not lift 6 ft bush hog on it's on but can lift by hand at the tail of the bush hog and it will lift and hold.. just needs a little help. Has new pump, fluid, filter. Suspect relief valve but don't know where it is located. Any help appreciated

 

[Harry in Ky]

Why would you suspect a relief valve unless you can hear it squealing? What have you tested (pressure wise) that would indicate a relief valve problem? Why was the pump replaced?

 

[Lanny Collins]

Why would you suspect a relief valve unless you can hear it squealing? What have you tested (pressure wise) that would indicate a relief valve problem? Why was the pump replaced?

No pressure readings have been taken. Friend bought tractor from neighbor and original problem was shuttle shifter not working. Friend tore down took apart. Not sure why replaced pump other than maybe he was there and didn't want to tear back down again. Got shifter problem solved but he felt hydraulics were weak. Have no real reason to question relief valve but had 2 local mechanics mention relief valve so thought maybe there was some adjustment on it that was allowing too much fluid to bleed off and return to holding resovoir.

 

[Lanny Collins]

No pressure readings have been taken. Friend bought tractor from neighbor and original problem was shuttle shifter not working. Friend tore down took apart. Not sure why replaced pump other than maybe he was there and didn't want to tear back down again. Got shifter problem solved but he felt hydraulics were weak. Have no real reason to question relief valve but had 2 local mechanics mention relief valve so thought maybe there was some adjustment on it that was allowing too much fluid to bleed off and return to holding resovoir.

Spoke with Friend. He said he replaced the pump thinking it may be bad and reason for weak hydraulics.

 

[Harry in Ky]

I see. Problem existed before the pump was changed and the new pump didn't solve it.

Not being at all familiar with that tractor I have no suggestions other than find a place to tee in a gauge somewhere and see what pressure the system is producing when loaded. That reading should tell you something. Without that, just looking for things to adjust is probably not a good idea.

 

[Roadworthy]

Some tractors have a screen in the hydraulic system which can restrict flow as they catch crud. Some have a hydraulic filter which serves the same purpose. Some have both. A diagram of the hydraulic system would be in order as well as a pressure check. Perhaps when he redid the transmission he reassembled something incorrectly. Did the problem exist before he worked on the transmission?

 

[LD1]

Yea, need to know the pressure before you go throwing parts at it or making adjustments to anything.

Does the tractor have a loader? If so, do those hydraulics seem weak?
When lifting from the tail and getting the 3PH to raise the bushhog, does it stay raised or does it bleed back off?
Does the engine seem to labor and struggle when trying to lift?
Does the tractor have draft control?
Was there an issue with the weak hydraulics BEFORE working on the shuttle shift?

I am suspecting if the engine dont labor at all trying to lift the 3PH...that you have an issue with 3PH valve. Maybe something didnt get put back together right? Feedback linkage?