The Stovebolt Site Forums The Shop Area General Truck Talk Brakes are siezed

I took the 51 out for a drive today and went a little longer than I usually do. I started smelling somthing hot so I went home and parked it. Now I just tried to go out and move her into the shed and the peddle is rock hard (no give) and she won't move forward or back.
Did I boil the fluid or can the pads stick to the drums? Just wondering what ya'll think.

Well, they cooled down and let go. Guess I am going to need some adjustments to them.

I had the same problem with my 46 last year (it drove me nuts!). It turned out to be a small vent hole in the master cylinder that relieves the fluid pressure in the lines. I cleared it with a tiny drill bit and used a magnet to make sure there were no metal chips in the MC.

Had the same problem with a Van back in England turned out too be water in the brake fluid.

I think I got it so hot that it expanded in the lines. I would think that if the brakes were in proper adjustment, then this probably wouldn't have happened, but I'm not sure.

Yeah I think if you have water in your brake fluid , And your brakes are dragging it heats the water up possibly too the point it makes steam this pressurises the brake system locking on your brakes as they cool down the steam will contract turning back into water and your brakes will ease off. This can then also allow pockets of air from the water boiling. Best bet too change out the nrake fluid and ease off the brake adjustment a bit .
Ryan

It happens when the brakes are overly adjusted and rub the drums constantly. Just need to back the shoes off enough for some expansion room,
Scott

How much free travel does your pedal have? If not at least an inch or better an inch and a half the rod from your pedal into the master cylinder needs shortened. This causes more brake drag than any other factor.

I don't have much travel at all. I've smelled it a little hot before, but this time I touched the front drums and almost got burned. I think I will back them off a little.
coilover, How can you tell how much needs to be taken off of the rod?
I had an old timer do these breaks, maybe I'll go talk to him.
Thanks guys for the replies.

If this is an original master cylinder, the pedal should return and stop moving because of a stop inside the master cylinder. You should have at least an inch of free play I would think.

Several things may cause this issue. The main ones are incorrectly adjusted master cylinder push rod that leaves the compensation port in the master to not be fully open and bad flex lines that have collapsed on the inside and do not allow all of the fluid to return.

When I push on the peddle, It basically starts to grab right away. There might be 1/2" of play, if that.
Sounds like maybe the rod does need to be backed off. Also, I did jack the truck up and the front wheels do drag quite abit when I try to spin them. Guess I'll be doing some work.
Thanks again,
Tim

Tim,

Before moving into any other diagnosis (or speculation), check your toe-board clearance adjustment (for the master cylinder), and then adjust the brake shoes. Note that the 1951 instructions state to adjust to tighten until you get a drag; then back off 14 "notches".

On my 1/2 ton 54, I tighten until the brakes shoes are really tight (to "seat" the shoes). Then, I start backing off until there is no drag. Then, I back off 7 notches (7 notches is what is called-for in the 1954 truck Shop Manual).