The Stovebolt Site Forums The Shop Area General Truck Talk Brakes locking-up on 51 Chevy 1/2 ton Pick-Up

All
This is all new to me, working on an old truck and trying to communicate the type of help I need. I have a 1951 Chevy ½ ton Pick-up, that’s in “OK” condition (it runs).
The problem that I am experiencing is this, after driving the truck for 5 or 10 minutes the brakes lock-up. I am not sure if it is all four wheels that lock-up, or just the front or just the rear. On one occasion I notice some smoke coming from the right rear wheel.
Note: After the truck is parked for 5 or 10 minutes the brakes release.
About a year and a half ago, I had a mechanic install new brakes and brake cylinders (Possibly rebuilt cylinders). Also, the Master Cylinder appears to in good condition.
I have not driven the truck very much over the past year and a half due to charging and electrical problems.
Note: I am not mechanically inclined. Any help or suggestion will be greatly appreciated.
C-Lee

Emergency brake maybe? Bad linkage or something bent linkage?

If it's the rear, pull the wheels and check for any oil leaking. If you have a bad rear seal it could be getting into the drum and swelling the brake linings.

If someone rebuilt the master cylinder ain the past they my have reversed the plunger stop when they reassembled it. That will allow pressure to be applied to the system but it blocks off the compensation port and it will take a good while for the pressure to bleed back and releas the brakes.
Denny Graham
Sandwich, IL

Check for free play in the master cyl. pushrod. It must have a small amount or it will hold the master cyl piston from coming all the way back like Denny says.

One more thing--check your hard brake lines to see if any are bent in or pressed together. Will let high-pressure brake flued through, but will keep the shoes tight for several minutes while it leaks down back through the clogged part.

Not as likely to be the problem, but I have heard of that and if my memory serves me correctly, I had it happen once way back in the day.

I had the same problem with my rear brakes, I cleaned and readjusted brakes after putting new return springs on the shoes.

I would check the brake line hoses. They really should be replaced every so often. In time they swell inside, so you can't see it. You press the brake pedal and there is enough presure to force past the restricted hoses but it can't easily flow back. It's also piece of mind to replace the old rubber hoses.

my 51 did the same it ended up being the rear seal leaking on the pads

could just be adjusted a little too tight.
Scott