FIXED Brake

[Geri]

Hello Truckers,

i have a brake problem with my 1953 Chevy Truck. I try to explain it.
When i start driving the truck after a longer standbye time ( for example more than 12 hours) and use brake pedal only a little bit, i get some full brakes with blocked wheels on the front side. Only on the front side and only after a longer standby.

After i drive back and forward with some brake pedal activitys (i still get full brakes and blocked wheels) the brake slowly works normal again .

I have drum brakes and allready changed one of the front wheel brake cylinder. But that was not succesfully :-(

Anyone ideas?

Best regards

Geri

[Henry50]

I'm not exactly sure what you mean by blocked wheels.

What master cylinder do you have and where is it mounted?

[OrrieG]

If you are locking up your front brakes after use my guess from similar experience is the rod into your master cylinder does not have the proper free play so the piston does not go far enough to release the pressure on the front line.

[dwcsr]

Originally Posted by Geri

Hello Truckers,

i have a brake problem with my 1953 Chevy Truck. I try to explain it.
When i start driving the truck after a longer standbye time ( for example more than 12 hours) and use brake pedal only a little bit, i get some full brakes with blocked wheels on the front side. Only on the front side and only after a longer standby.

After i drive back and forward with some brake pedal activitys (i still get full brakes and blocked wheels) the brake slowly works normal again .

I have drum brakes and allready changed one of the front wheel brake cylinder. But that was not succesfully :-(

Anyone ideas?

Best regards

Geri

Es klingt, als hättest du Luft in den Bremsleitungen. Wenn Sie es auf Deutsch erklären, können wir es auf Englisch übersetzen und Ihnen besser helfen. Wir wissen nicht, was Sie mit "blockiert Rad"

[mr48chev]

This looks like a "Dave to the rescue" situation.

Still you have to look at the usual.
Master cylinder and wheel cylinder in good condition.
All lines and hoses in good condition and all fittings tight.
Shoes in good condition and adjusted correctly.
Free travel on master cylinder push rod adjusted correctly.
Brakes bled correctly with no air in the system.
With that you should have pretty decent brakes.

[Geri]

Thanks everybody for the fast answers.

I try it again to explain the blocked wheels: ;-)
Normally the wheel still rotates even if i step on the brake easily. In my case the wheel stops abruptly and get blocked/locked. Rubber on the street are
consequences.

For the first time i will follow our note with the master cylinder and the air in the brake pipes.
I will post my results shortly.

Thank you again.

Greetings from Germany

[Henry50]

It sounds like a wheel cylinder has leaked brake fluid on the shoes.

[dsraven]

I will have to say it sounds like contamination on the brake linings. if all else is good, like mr48 says, then this could be the place to check first. brake lining material is sort of like a sponge when it comes to contaminants. you could have axle grease contamination on the shoes, soak the overnight in brake cleaner and dry them off. they look good but the first time they heat up the contaminants are right back again. a little bit of grease or brake fluid on the shoes will make the wheels lock up with a light brake application. do you still have the original single brake circuit style of brake master cylinder?
things to check-
-brake pedal returns to top of stroke after an application. simple pull up on the pedal to see if it is at the top or resting slightly lower. if it is not at the top then check for a linkage issue.
-check all the linkage pivot points and clevis pins etc for wear or siezing up areas. a little bit of wear in a couple of joints can mean the adjustment of the master cylinder pushrod cannot be made to be the same after every pedal push. this can lead to a pushrod that doesn't return all the way so fluid is actually trapped in the brake system.
-ensure the master cylinder pushrod clearance is within tolerances
-check all the brake flex hoses for cracks and/or soft spots on their entire length. repair as required
-check all the brake steel lines for corrosion, kinks, dents from rocks and/or road debris. repair as required
-check to ensure the parking brake is operating and returning fully after use. back the park brake off until after the brakes are adjusted to ensure a proper adjustment can be made
-adjust all the brakes on all 4 wheels. it is a good idea to remove the drums and check all the hardware, wheel cylinders and linkages for proper operation. check the wheel cylinders for seapage by pulling back the dust seal on the end of the cylinder and checking for seapage that has made it past the wheel cylinder cups. also check for worn backing plates in the areas where the brake shoes rub the backing pates. this can allow the brake shoes to fall into a groove worn in the backing plates over time. this means the shoes don't return to center properly after an application and can lead to troubles with adjustment and improper brake operation. with the drums off but the brake shoes still assembled you should be able to move the shoes in such a way that you can check that the wheel cylinder pistons are moved easily in their bores. check the brake drums to ensure thay have a nice clean surface and are not grooved up too badly. a lot of guys will install new shoes but use the old drums, to save some cash. this can mean that the new shoes wear quickly to conform to the pattern of grooves inside the old drums. it can also mean there is a large bump at the outboard and inboard surface of the brake surface, where the shoes rub. depending on how tight the wheel bearings and rear axle "C" clip retainersare, the drums can "move" side to side a bit. this can mess up your brake adjustment. I usually adjust the shoes up tight until the wheel is locked. then adjust them back a certain number of bumps on the star wheel adjusters until the wheel turns freely, then hit the brake pedal a few times to ensure the shoes are centered and see if the wheel spins freely. if it does I may adjust a click tighter and repeat the procedure with brake application until I am satisfied that the shoes are adjusted to be as tight as possible without causing drag and wear, and the pedal is at an acceptable height. all the wheels get the same treatment with the same number of turns back using the worst wheel as a baseline for adjusting the rest. of course there is a spec somewhere but I don't usually have that handy at the time.
-adjust the park brake after the service brakes have been adjusted.

[Jemezcrusher]

Originally Posted by henry50

it sounds like a wheel cylinder has leaked brake fluid on the shoes.

x2