I had the suction tube off the hydraulic & steering pumps to do other repairs. When I first restarted the tractor I had no hydraulics or steering, so I pulled the suction tube back off and filled it with fluid to help prime the pumps. The hydraulics came back immediatly, but the steering took awhile. After that when I first started the tractor the steering wouldn't work for awhile, maybe as along as a minute or so, then start working and be fine until you shut the tractor off. Now I have no steering at all, but the PTO will come on, and I know they are on the same circut. I have installed a gauge inline on the PTO supply tube. The gauge reads about 325PSI. What should the pressure be? Could I have a problem with the relief in the PTO valve. If anyone has any ideas I would greatly appreciate them. Thanks, Len
M9000DT-CAB Steering Problems
- Thread starter Len
- Start date
Len - Welcome to the OTT!
What other repairs where you doing that you had to have that line off?
Try to self bleed the system by repeatedly operating all thing operated by your hydraulic pump. Sounds like you almost had the steering and stopped just too soon. Cycle it a lot.
For the pressure readings, yours sounds kinda strange at 325psi. obviously way too low. If that is indeed what you are having for hydro pressure then that is your problem.
Go to this link and scroll all the way down to the bottom. It says delivery pressure is 2205psi and sustained pressure with relief valve open is 2845psi.
What other repairs where you doing that you had to have that line off?
Try to self bleed the system by repeatedly operating all thing operated by your hydraulic pump. Sounds like you almost had the steering and stopped just too soon. Cycle it a lot.
For the pressure readings, yours sounds kinda strange at 325psi. obviously way too low. If that is indeed what you are having for hydro pressure then that is your problem.
Go to this link and scroll all the way down to the bottom. It says delivery pressure is 2205psi and sustained pressure with relief valve open is 2845psi.
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Thankyou for the reply and the welcome. I had the line off because I split the tractor to replace the transmission clutch. I've had it off before when I pulled the timing cover to repair the engine oil pump. That time both the hydraulic and steering/PTO pumps primed right up on their own. I have good system pressure on my main hydraulic pump. The steering and pto share their own pump and relief and that is where I have my gauge. I'm getting 325psi at idle and about 490 at wot. The steering doesn't work at idle but does at 1500 rpm on up.
That doesn't seem right. If there is no possibility to have any obstructions in line after putting it all back together than I wonder if the pump cavitated and now lost the ability to supply adequate pressure 
Some pumps do not like to run dry for any amount of time as the hydro fluid is also a lubricant for the pump. If it's an older pump it may have been the death blow. Just thoughts
Some pumps do not like to run dry for any amount of time as the hydro fluid is also a lubricant for the pump. If it's an older pump it may have been the death blow. Just thoughts
Thats what I've been afraid of. I pulled and disassembled both pumps to inspect them. The internals of the hydraulic pump do look better than those in the steering pump. They share alot of the same parts so I put the best looking ones back in the steering pump and put new seal kits in both pumps. I'll see if my steering gets better and my main hydraulics suffer. The parts in the steering pump didn't look awful, just not as good as the hydraulic pump. I had a simular problem before with a hystat unit. I took that thing apart several times to inspect it and could only find minor scratches. That time it was the pump too. It would only produce 1500psi instead of the 6000psi it was supposed to. I couldn't believe minor scratches cold cause a 4500psi pressure drop, but they did. I'm afraid that is what I'm looking at again though.