1948 Special Deluxe Brake locked up, maybe

[John T]

This is a little odd, brake was pulling on driver's front.  I replaced the hose and still pulling but not as bad.  Went to the passenger rear and bled brakes, got pressure up, did the drivers side rear.... reversed the car out into the cul-de-sac, shifted to 1st and front brake pulled down hard on driver's side.  tried a couple of more times and would not go forward.  Moved back in reverse 4 feet, tried going forward and it went about 4 feet and drivers brake pulled down and stopped.  Eventually was able to get the rear turned around 4' at a time and back in the garage.

BUT, how in the world if the brake is locked am I going in reverse?  Before I start taking things apart, anyone else have this problem, locked forward, reverse works?

Understand, I am 50 years late on learning to work on old cars but enjoying it, when they work!  Thanks.

 

[TodFitch]

Check that the relief port in the master cylinder isn’t blocked or clogged.

[keithb7]

Does your car have 2 single wheel cylinders on the front wheels. 1 upper and 1 lower? 1 activates the front facing shoe, another cylinder activates the rear facing shoe. 

 

Eventually brakes were designed to be self energizing. As you brake while travelling forward, the brakes pull themselves to dig-in deeper and brake harder. This primarily occurs when driving forward. 
 

Maybe a couple clues to help you out?

Edited July 23, 2023 by keithb7

[D35 Torpedo]

I think Keith is onto something. Because the shoes pivot from one end, in one direction they will self energize, and the other not. I've had the problem before, when reversing and hitting the brakes, something would shift so that when I went forward I would hear a scraping noise. At that point I'd jab the brakes hard, it would kind of clunk, and then be fine again. I found a good accurate brake adjustment fixed the issue.

[Ivan_B]

I would recommend going over the brakes in the following fashion:

 

1) Lift one wheel of the ground, ask an assistant to floor the pedal hard then release. Try to rotate the wheel by hand, in both directions, is the wheel properly releasing? There should not be any resistance, the wheel should spin freely once you get it going. Try this several times, to make sure that the brakes do not grab while the pedal is released.

2) Repeat p. 1 with all four wheels individually, to find the bad wheel/wheels.

3) Properly bleed the brakes (all wheels, in the correct order).

 

If the above does not help, take the bad wheel/wheels off, inspect the drum, shoes, check if you can compress the slave cylinder with pliers (etc.). Also, if you have self-adjusting cylinders installed in there, by chance, do not attempt the pliers trick, it will not work

[kencombs]

On 7/23/2023 at 6:57 AM, John T said:

This is a little odd, brake was pulling on driver's front.  I replaced the hose and still pulling but not as bad.  Went to the passenger rear and bled brakes, got pressure up, did the drivers side rear.... reversed the car out into the cul-de-sac, shifted to 1st and front brake pulled down hard on driver's side.  tried a couple of more times and would not go forward.  Moved back in reverse 4 feet, tried going forward and it went about 4 feet and drivers brake pulled down and stopped.  Eventually was able to get the rear turned around 4' at a time and back in the garage.

BUT, how in the world if the brake is locked am I going in reverse?  Before I start taking things apart, anyone else have this problem, locked forward, reverse works?

Understand, I am 50 years late on learning to work on old cars but enjoying it, when they work!  Thanks.

 

IME, grabbing/locking brakes have always been caused by brake fluid leaking onto the shoes.    Worth taking the drums off and examining everything inside.   Springs, shoes, everything.    The reason for it being directional was explained by another poster.

[Dan Hiebert]

Broken brake shoe return springs will cause that, too.  I had about a two year span when one of the shoe return springs would break every two or three months, causing the exact same thing to happen.  All had come from the same vendor, too long ago to cast aspersions about product quality now.

[John T]

Thank you gentlemen, I will get back to this as soon as I get my daily driver running.  Always something!