Brake issue

[graham_fuller]

Hi guys
My rear LH brake locks on for the first 8-10 times I brake. What's been done? The hydraulic fluid has been replaced and brakes adjusted. The problem existed less before these 2 things were done that's why it was worked on. All brake hoses were replaced about 5 years ago. Any suggestions what the problem might be?
Cheers,
Graham

[ardiesse]

Graham,

The problem you describe normally affects the front brakes.  Holden even published a service note about it, where they labelled the condition "morning sickness".
It affects cars that haven't been driven too much, and is made worse by humid weather.

If you've got the car parked facing downhill with the handbrake on, and you release the handbrake, does the car refuse to roll forward unless you reverse a little first?

A quick fix is to take the offending drum off, and de-glaze the linings with coarse sandpaper.

But while you've got the offending drum off, it's a good idea to check for the following conditions:
- shoes adjusted too tight.  Back them off.
- handbrake not releasing properly.  Clean and oil the handbrake cable where it runs through the outer.
- seized or sticking wheel cylinder pistons, particularly the one that faces forward.
- brake fluid leaks.
- gear oil leaking out of the rear axle onto the brake linings.  Although this makes the brake not work at all.

If these checks reveal nothing out of the ordinary, it's time to start looking for more subtle things:

- linings not properly bonded to the shoes, particularly at the leading edge (top for the primary shoe)
- weak, broken or fallen-off brake shoe retractor spring.
- Sometimes grinding a shallow chamfer about 1/2" wide all the way across the leading edge of the primary lining will help.

In really stubborn cases, the only cure is to drive the car more often.

Rob

[graham_fuller]

Thanks Rob,
Do think it's possible the brake hose is the problem? I have never had this issue before.
Cheers,
Graham

[REDMR2RED]

I just had a similar problem. Rolling up to the lights the brakes would stay on even when I lifted the peddle to roll to a stop.  Then when I took off the brakes stayed on for a bit.  I did what you did change the fluid, adjusted the brakes which made it worse.  Bit the bullet and pulled them down, the front shoes on the front wheels were due to be relined the rest were still plenty of meat.  All the rear pistons in all four wheel cylinders were locked in tight what at first looked like rust but on closer inspection appeared to be solid gummed up grease.  Cleaned everything, new set of rubbers in all wheel cylinders, fresh brake fluid, new linings, reassembled, bleed, adjusted and everything is back to normal.  

[graham_fuller]

Thanks for the tip will redo the wheel cylinders.
Cheers