JD 750

J_J · Jun 24, 2015

DeereDoug said:
Hello,

I have a <2K hrs 750 compact tractor and I just replaced the hydraulic filter, fluid and cleaned the strainer. I found plenty of metal flakes in the strainer and some tiny pieces at the bottom of the pan which leads me to think that the hydraulic pump should be replaced as well.

My problem is that both the FEL and 3 point hitch seems to stall "screech" when lifting minor loads. I know from reading that both ends should be able to lift ~800lbs. and I have yet to meet this. My rear 60" mower ~500lbs. and I can just lift it a few inches at best.

I found a pump, but need to call to check if it is either rebuilt or new. Also, I am thinking about constructing a pressure and flow meter assembly to measure things, but kinda unsure on where to start with that. I do have a TM but its not helpful on building one or wear to attach such.

Any diagnosis or assistance would be most appreciated.

D.

The reason that you can't raise the rated load is that your hyd system can not develop the pressure required.

This could be due to several reasons.

Worn pump, worn piston seals, worn spools in the valves or a combination of problems.

The rate of descent is just that it will adjust the rate of drop for the load as you want.

It can be used for transport by closing off the valve.

You should have a flow and pressure check before tearing into the hyd system.

prs · Jun 26, 2015

Tx Jim said:
May I ask why valve needs to be fully open as that would defeat the purpose of the "rate of drop" of 3 pt capabilities???? R-O-D screw was designed to limit lowering speed of 3 pt with a heavy load on 3 pt which can only be accomplished by partially closing the valve. I think OP needs to check system pressure with a gauge.

Jim, Because the Owner's Manual says so? The valve in question is a shut off valve on the main line going to rock shaft. The speed of drop valve is located, on the JD750, on an eccentric arm between the rock shaft lift arms.

Rooster

DeereDoug · Jul 7, 2015

I want to thank everyone's input on this, after I repair my MFWD repair I will investigate this. http://www.tractorbynet.com/forums/parts-repairs/339894-jd750-mfwd.html

I do understand checking the pressure of the system before tearing things apart, but unsure as to how to approach that. DO I ned to order a length of hydraulic line and pressure gauge, so as to screw it into the line somewhere? A walk through if someone is willing to write-one up would be most appreciative.

D.