This is a military crane and the data plates and manual all give conflicting info as to the manufacturer. One says Terex, one says Lorain, one says Koehring. So here's the problem; someone noticed that it was spitting fluid out the winch drum vent when the engine was idling. So we popped the motor off to see if was the motor seal or brake piton seal. When we first took the motor off we disconnected the hose to the brake and capped it off. I had no signs of any fluid getting into the drum. I hooked the line back up & there it was. So I know the brake seals need to be replaced. I was reading the theory and operation of it though and I dont think I should have any fluid going to the brake with the engine merely idling and no levers being stroked. So I'm attaching an excerpt of the hydraulic schematic, the theory and operation section of the manual I have, and a pic of the set-up (still dismounted from the brake assembly).
Winch Theory of Operation
The winch is made up of four basic assemblies:winch base, hydraulic motor and brake valve, brake cylinder and motor support, and drum assembly. The hydraulic motor turns the gears in the drum assembly, working the cable. The winch has a dual braking system: a dynamic brake and a static brake. These two types of brakes work together to control the speed of the drum assembly. The dynamic brake uses hydraulic pressure to operate the brake valve which
controls the flow of hydraulic oil to the hydraulic motor, The static brake is made of multiple friction discs, a brake clutch assembly, and a hydraulic piston and cylinder. The static brake is automatically applied unless it is released by brake valve pilot pressure at a level lower than that required to open the pilot-operated spool valve. Either brake system does not affect the winch during hoisting operations. When the operator’s control is placed in neutral, rollers between the cam and outer race wedge to prevent the drum assembly from turning. The brake valve stops oil flow from the hydraulic motor. For lowering a
load slowly, the operator can allow only enough oil to release the brake without engaging the hydraulic motor. The heat build-up is dissipated by
the hydraulic oil. For faster lowering, the hydraulic pressure is increased by the operator to both release the brake and engage the hydraulic motor.
Winch Theory of Operation
The winch is made up of four basic assemblies:winch base, hydraulic motor and brake valve, brake cylinder and motor support, and drum assembly. The hydraulic motor turns the gears in the drum assembly, working the cable. The winch has a dual braking system: a dynamic brake and a static brake. These two types of brakes work together to control the speed of the drum assembly. The dynamic brake uses hydraulic pressure to operate the brake valve which
controls the flow of hydraulic oil to the hydraulic motor, The static brake is made of multiple friction discs, a brake clutch assembly, and a hydraulic piston and cylinder. The static brake is automatically applied unless it is released by brake valve pilot pressure at a level lower than that required to open the pilot-operated spool valve. Either brake system does not affect the winch during hoisting operations. When the operator’s control is placed in neutral, rollers between the cam and outer race wedge to prevent the drum assembly from turning. The brake valve stops oil flow from the hydraulic motor. For lowering a
load slowly, the operator can allow only enough oil to release the brake without engaging the hydraulic motor. The heat build-up is dissipated by
the hydraulic oil. For faster lowering, the hydraulic pressure is increased by the operator to both release the brake and engage the hydraulic motor.
LRT 110 Winch hydraulic issue
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