3 Pt. lift weak when machine is hot

[PlanMan]

Looking for help here - After brush hogging for about an hour I took about a 10 minute break with the tractor shut off. When I started the tractor again, the mower would not raise when the tractor was idling, but did raise very slowly when engine speed was at full speed.

I experienced this last fall also with the FEL being weak after working the machine hard at length putting in a new driveway.

Unit is old - '90 B7200, but has an honest 370 hrs. on it. I changed the Hyd. oil last fall using the high-end oil @ TSC. I've read on here about problems from not using the Kubota UDT oil and am wondering if this is the problem.

Thanks in advance for any help.

 

[Volfandt]

I've read on here about problems from not using the Kubota UDT oil and am wondering if this is the problem.

The odd's are it is the hyd oil.
As you indicated theres been many folks thats posted about similar problems using, shall we say cheaper hydraulic oil in their Kubota's.
Most of the older Kubota's call for std UDT which is a single grade oil. Most that went back to Kubota UDT had good results.

Newer Kubota's call for SUDT which is a multi-grade oil and is more expensive. Many that tried to save a few $$$'s and tried std UDT had problems similar to yours and corrected them when they went back to SUDT.

Theres been a few others that operate in very hot climates that experienced similar problems such as yours and went with a synthetic Chevron multi-grade oil over the Kubota SUDT and this cleared their problems up.

In any case, I'd change the oil back to UDT and change the filter as my 1st course of action. This'll probably straighten it up.
Good luck.

 

[PlanMan]

Thanks Volfandt, I'm changing it out tomorrow.

I have a partial jug left, the fluid I put in is:
Citgo Mystik JT-5 Universal Tansmission - Hydraulic Fluid
states it exceeds specs for the following (lists most all tractors manuf. oils) and listed UDT under Kubota.

Thought I was safe. Thanks again.

 

[N80]

It might be the hydraulic fluid, but I'd definitely be looking for other reasons for this type of behavior.

 

[KennyV]

Before you change out your fluid… check the pressure, both cold and hot. You may find the pressure relief valve needs a new spring or shimmed… KennyV.