Overhauling Cleveland Brake Cylinders
The Cleveland Cylinders are using an O-ring for sealing the piston in the cylinder. Mine were leaking both after around 25 years of use. But only during the winter time when temperatures dropped below freezing. Then the low temperatures shrink metals and rubbers, and fluid was contaminating the brake pads. (O-RING AN6227B-27 - MS28775-222 or O-RING MS28775-224)
Seeping fluid
Fluid collected in the brake cavities, contaminating the brake pads
Piston with old O-ring - you can pop the piston out with compressed air, be careful not to create a bullet hitting your face.
The hydraulic fluid can collect water that can corrode the cylinder if progressed - bad news
Corrosion on the exposed part of the cylinder
old and new O-ring and cleaned piston
new O-ring fitted - ready for assembly
Note the clamping bolts holding the brake pads and assembly are filled with a nylon insert to make them self locking. Only substitute with similar from Parker Brakes. Or use bolts with drilled heads that you safety wire.
Assembly back on the wheel. The unit had been cleaned and painted. Note that the assembly is actually mounted upside down in comparison to cars, thus the brake pads are pointing down and are easily contaminated. Also venting the brake system cannot be done in the usual manner - e.g. pumping the brake pedal. It must be done in reverse by pressing fluid from the vent valve up into the brake master cylinder into the reservoir. It can be done with a big syringe.
Hartmut