JD CT 322 with locked up breaks

OldAllis · May 8, 2020

I've got a Deere CT 322 skid steer and the parking breaks will not release now. Ever since we got it the breaks would seem to start dragging now and then while using it. You would have rev it up and move it back and forth a couple of times and it would loosen back up. The joystick levers would also get stiff like there was too much pressure in the hydraulic system. Then a couple days ago it locked up and would not let off. We checked the seat belt switch and the seat switch, they were good. We replaced the solenoid for the parking breaks, did nothing. How ever the breaks did release a little when we repleaced the solenoid, figured it was because some pressure was relieved in the process. Would a bad relief valve cause this? And where are the ports located to check the hydrolic pressure?
Any wisdom would be greatly appreciated. Thanks

OldAllis · May 8, 2020

It is a 2007 JD CT 322 and the Serial# is T0322TA144153

OldAllis · May 17, 2020

I have now eliminated it being a wiring problem by running though the park brake circuit which checked out and then manually controlling the park brake solenoid. I have moved on to the hydraulic system now. To me it seems like something is either clogged or malfunctioning not letting the fluid pressure to properly release untill you raise and lower to boom. (Yes we found out that if you raise and lower the boom a couple times the brakes will temporarily release until the machine heats up then they lock back up until it cools down again.) Something may be letting pressure in when it shouldn't be. The park brake solenoid is mounted in the edge of a flat box. I was wondering if this box could be the problem? Or if there are other components in the system that should be checked? Is there another way to check hydraulic pressure than where the book says? I'll have to get the fittings to check system pressure. This machine was missing the port for whatever reason.

jd2cylman · May 17, 2020

If the JD's are anything like NH machines, your park brake is operated by charge pressure, not system pressure. So, a minimum of 200psi. Probably should be in the 350ish range. When you replaced the brake solenoid, did you replace the whole solenoid and valve cartridge, or just the magnet coil? I've had the valve inside the cartridge stick before. More heat would make the cartridge stick possibly. That's all I can offer at this point. I'm a NH skid mechanic, so apples/potatoes... :wink:

JD CT 322 with locked up breaks

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