TO30 Hydraulic issue

[cgejimmy]

I have a TO30.

We recently rebuilt the hydraulics with a rebuild kit. We also replaced the piston with the Ford piston with the rubber and leather O-rings. We changed the control valve and relief valve.

Everything was working fine until yesterday. We shredded a small section and hydraulics worked fine. When we went to raise the shredder up to take it back to storage the hydraulics would not lift it.

We unhooked the shredder and put a drawbar on the arms. The arms will lift. But if you put any weight on the drawbar they will go back down. I weigh 250#. I stood on the drawbar but it wouldn t raise me. I can feel the pump trying to raise me while standing on it.

Any ideas where to start looking?

 

[Jerry/MT]

It sounds like you have a leak somewhere. You may also have a sticking control valve.

With the engine running and the right hand side plate off, move the lift lever to the max raise position, Using a
flashlight, look up at the lift cylinder to see if it's leaking. Anything more than a few drops is a leak. Next look
at the right front corner of the hydraulic compartment with lift cylinder oil supply tube is located. If you see
fluid streaming down there, the o-ring that seals the tube against the lift cover is leaking. If the relief valve is
leaking there will be a lot of turbulence near its location and it maybe noisy. Look at the joints of the pump and
see if there is leakage from the pump gaskets. Finally, WITH THE ENGINE SHUT DOWN, reach into the oil and feel the T
shaped control valve. Both ends of the T should be in their respective sockets on the H shaped control fork and the
control valve should easily move fore and aft about an inch. Look at the control linkages and verify that it is all
hooked up correctly.

 

[cgejimmy]

Jerry, thank you for the clear and concise explanation. The lift cover gasket was damaged when we installed the lift cover and was covering the lift cylinder supply tube which was causing it to leak back down to the pump.

We didn t see any more leaks.

We have a new gasket coming this week and that should fix it.

Thanks for your help.

Jimmy

(quoted from post at 19:14:30 09/19/23) It sounds like you have a leak somewhere. You may also have a sticking control valve.

With the engine running and the right hand side plate off, move the lift lever to the max raise position, Using a
flashlight, look up at the lift cylinder to see if it's leaking. Anything more than a few drops is a leak. Next look
at the right front corner of the hydraulic compartment with lift cylinder oil supply tube is located. If you see
fluid streaming down there, the o-ring that seals the tube against the lift cover is leaking. If the relief valve is
leaking there will be a lot of turbulence near its location and it maybe noisy. Look at the joints of the pump and
see if there is leakage from the pump gaskets. Finally, WITH THE ENGINE SHUT DOWN, reach into the oil and feel the T
shaped control valve. Both ends of the T should be in their respective sockets on the H shaped control fork and the
control valve should easily move fore and aft about an inch. Look at the control linkages and verify that it is all
hooked up correctly.