I am still looking for a service manual, but in the mean time i am hoping for some help. The crane has a hydraulic brake on the hoist motor that is release with hydraulic pressure when the hydraulic motor for the hoist drum is activated. The brake is leaking a ton of hydraulic oil out the side that is opposite the motor (drum gear side for lack of knowing what it is called), this eventually fills the case and runs out. I took it apart and nothing obvious is broken, and the old owner swears it didn't leak when they used it. Is there anything someone can point me to look at?
usually, the brake pack piston seals give up and start leaking your brake pressure. So while the winch is moving, your brake release pressure is bypassing. Usual fix is the build the hoist brake. New frictions, spacers, seals/orings……
Thank you, any idea where I can buy a rebuild kit?
Some more information, when we cable up there is 27 psi on the brake, but when we cable down 350 psi on the brake and it causes the brake to leak. I just wanted to see if this adds to anyone's thoughts. Thanks!!!
Typically, there is a overrunning clutch for cable up. Brake pack then doesn't release on cable up. You need brake release for cable down, that's why you have all the pressure on cable down, it has to provide enough pressure to overcome the spring pressure on the friction disks, to cable down. As mentioned above, most of the time the seals go on the brake pack, putting hydraulic release oil into the gear oil of the winch. Shouldn't be anything exotic for seals. Unless the frictions are bad, I never replace them, I doubt yours has done enough lifting to wear out a set of disks, plus those will be hard to find. If it's been sitting, it doesn't surprise me to have a leaking brake pack. Just be sure to drain and refill the gear oil in the winch, removing the hydraulic oil that's leaked in there.