Hydraulic Lift Problems

[mdonalds201]

My TO30 lift arms will not stay in the up position when the PTO is disengaged and a bush hog attached. The mower will slowly lower until on the ground (3-4 min.) Also after using the bush hog for several hours, the lift arms have a hard time picking up the mower since the fluid is hot. Does this sound like the lift piston rings or is the problem in the pump. The arms lift & lower with no problem, jerking, etc. Any suggestions?? Thanks, MJD

 

[Jerry/MT]

On the face of it it sounds like a leak in the system, eiher the cylinder or the supply tube to the cylinder. It cold be a partilaly open relief valve too.
Have an implement on the three point, open the side plate, start the engine and engage the pto move the lift lever up, look for leakage from the lift culinder(UNDER NO CIRCUMSTANCE PLACE YOUR HANDS INTO THE HYDRAULIC COMPARTMENT WHEN THE ENGINE IS RUNNING!). using a mirror look into the right front corner at the supply tube. look where the control valve is on th epump. If there is alot of turbulence and noise, then the relief valve is stuck partially open.

 

[mdonalds201]

Thanks, will do. MJD

 

[Randyr]

One other thing.
Have you changed the oil recently?
This sounds like it could be a problem that is known to happen in the old tractors when TDH oil is installed. It"s real thin and is fine for the newer stuff, but not so good in the old stuff when hot because of it"s low viscosity.
Best stuff is GL1 80w90 or 15w40 diesel engine oil which many people have switched to due to availability and price. It"s a good all temperature oil.

 

[westwood]

my 165 did the same thing and it ended up being that the pump was bad. does it stay down till it cools off? pressure relief valve also

 

[mdonalds201]

No I changed the fluid and replaced with UTF which is 85W. I was hoping not to pull the pump and get away with the lift piston rings. Guess I need to get dirty again. Thanks, MJD

 

[John (UK)]

First of all, this system was never designed to hold up any weight indefinitely like some newer tractors that use a different system.
The Hog is a heavy implement and if there is any wear in the system it will leak down, even so 3 - 4 mins isn't too bad for that weight as you are close to the maximum that the system can lift. The PTO should always be left running when you transport the Hog BUT you should remove the PTO shaft from the implement while you do this. This applies to most implements but there are exceptions, (these exceptions, usually they have separate ways to lock the implement in the raised position) so leave the PTO running to carry the implement or it may drop as you have found out. BUT NEVER park any implement in the raised position with the engine or PTO stopped as it can cause the Control Valve to stick.
If you want to check further then do this:-
Remove LEFT side round cover, start engine with PTO in drive with the lift lever in raised position and with Hog mounted on 3 point, engine at fast idle speed. Look in the top towards the rear and see if any oil is leaking from the Lift Cylinder open end, if it is, then it is the Piston Rings or Cylinder that is worn. If there is no visible leak there look in the bottom at the pump,this is straight in front of the round port, if there is any oil spraying anywhere, that is source of leak. Look at front right side top and bottom for leaks, if there is, then a gasket needs to be changed. If there are no visible sign of leaks, change the Safety Valve, it could be the Safety Valve or the Check Valve which is located on the end of the Safety Valve, both of these will cause the problem you have. The Safety Valve will leak if it has been discharging continuously for any reason, but the Check Valve will leak due to wear. From how you describe it I would think that it is the Safety Valve/Check Valve that needs replacing as anything else would allow it to drop more quickly. The Check Valve wears as it is operating all the time the Pump is running and it removes the back pressure from the Pump when you have any weight on the 3 point.NEVER PUT YOUR HANDS INSIDE IF THE ENGINE IS RUNNING
If anyone needs written information on what to look for and how to do it or has any other hydraulic problem, email me and I will send it. DO NOT tear down the system until you locate the leak or you will not be able to find [email protected]

 

[John (UK)]

15W/40 oil is OK to use but NOT the diesel engine oil, as that contains more detergent than the oil used in a gas engine. If it has more detergent it will keep any crud floating around in suspension in the oil and this will pass through the Pump and valves under pressure and cause wear. Use the gas engine oil and it will be fine. Plus the multi-grade is better than the GL1 type because it remains more fluid at cold temperatures, while the GL1 type thickens like [email protected]

 

[John (UK)]

I forgot to mention in my last post that the oil in the transmission should be 10W/30 or 10W/40 depending what is available in your area. This is a multi-grade oil suitable for a gas engine (not diesel) which will remain fluid in cold temperatures (unlike the GL1 type) and is still thick enough to provide the correct lubrication for the Transmission and rear [email protected]

 

[Rob Tholin]

I had the same issues w/ my To-30.
I had turbulense in the right side of the pump. I may have a video if you want to see it.
Then I pulled the pump and find a twisted PTO shaft. The fault was a wore out O-ring on the side chamber.
Few inches of sludge in bottom didn't help either.
I ended up with a extra set of lift piston rings.
Email me if you want to purchase them. Save a few $
(I'm located in Illinois)
I also replaced the safety and check.
Since then I have moved on to leaky axle seals on brakes.
ROB THOLIN
P.S John (UK) thank you for all your help on this site.

 

[mdonalds201]

Thanks to all for the replies. MJD

 

[John (UK)]

Anytime Rob....anytime.....John