The Stovebolt Site Forums The Shop Area Driveline Brake pedal free travel

I have a completely stock 53 Chevy half ton than I have been using occasionally for the last 20 years, before which I completely rebuilt the entire brake system with new parts. I have had no problem with the brakes until I drove it on a rather long trip to a swap meet ; about 60 miles round trip. As i reached home on the return trip , I noticed I had virtually no free travel on the brake pedal. The brakes still engaged and stopped the truck without pulling to one side or another. The brakes now engage on contact with the pedal and I feel they might be staying partially engaged during driving. There is no mushiness and engagement is very firm. It feels like the system pumped itself up during the drive without my doing and stayed pumped up. I suspect a faulty master cylinder but hope someone on this site can advise me before I throw money at it. Thanks George

If the master cylinder is engaged enough that it closes the hole from the reservoir, then heat from the brakes could cause the fluid to expand and cause what you're feeling. There should be enough free travel in the pedal that you see an initial spurt of brake fluid into the reservoir when the cap is off and the pedal pushed. A re-adjustment of the master cylinder pushrod should take care of that. If you continue to drive it that way, it'll wear the shoes prematurely

You say that heat from the brakes was the cause. Than might explain why my problem arose after a long trip. My shop manual is for 1951 models with a 1952 supplement and was not much help for me. I will try to adjust the rod to give about an inch of free play and see if it solves the problem.

When you are under the truck, move the brake pedal lever back and forth a little bit. There should be a tiny bit of play in the clevis of the master cylinder push rod. The pin in the clevis should be free to pull out when the brake pedal is released. It the pin is not free, then you need to loosen the lock nut on that push rod and turn the push rod until the pin is free. There is a knurled section of the push rod to grip with channel loc pliers.