1977 Ford F250 Wheel Brake Cylinder
My 1977 Ford F250 wheel brake cylinder on the right rear finally gave up. I thought the brakes felt a little spongy over the past few months, but I drive this truck very little, and just decided to pass the issue off. Well, after starting the beast one morning and pushing on the brakes only to find them less than responsive, I decided I needed to do something. My first option was to check the brake master cylinder for fluid. I found it in needing some, but it was not empty, and that was a good thing.
Hoping the fluid and a few good pumps on the brake pedal would do the trick, and give me the brakes that I was used to, failed miserably. The brakes just would not stay pumped up. That was when I decided to look for the problem. Sure enough I found a leaking right rear wheel brake cylinder leaking more than I had ever seen one leak before. It would just run out and down the tire with each pump on the pedal. It was a catastrophic failure, and I am glad it did not happen when I was driving.
I proceeded to remove the rear tire, brake drum, and replace the wheel brake cylinder. After removing the tire, I then removed the axle shaft lock bolts (40-50 ft. lbs. of torque), and removed the axle. Then I bent the locking tabs back on the lock washer that is behind the outer lock nut (90-110 ft. lbs.) and removed the outer lock nut. I used a chisel and carefully tapped counter clockwise to remove this nut. After removing this nut and the lock washer, I carefully chisel tapped loose the second inner locknut (50-80 ft. lbs. while rotating the drum, then back off 3/8 of a turn for reassembly).
After I loosened the brakes through the adjusting hole on the back side of the axle housing, the brake drum was now able to be removed. After removing the drum I was able to remove one brake shoe to better access the leaking wheel brake cylinder. I loosened the hydraulic brake line at the back of the cylinder and removed the two bolts that held the cylinder to the back of the drum assembly. It came off very easily in my hands. Then I reinstalled the new wheel brake cylinder, brake pad and hub in the reverse order from which they were removed. I made sure to grease the both bearings (good to do until the differential oil can get to them) and the inner bearing rubber seal.
I reinstalled the inner locknut, washer, and outer locknut, making sure to get them to torque, and bent the washer locking tabs over the outer locknut. I purchased a socket for this job which made it possible to get the nuts to proper torque. There is a link to purchase the socket after this article. Finally, I put the tire back on, adjusted the brake shoes and bled the brakes. I then topped of the differential fluid rather than changing it, as the old fluid still looked good. A video of my repair is presented below.