Rear brakes rub when first starting out

[Johnniemccoy]

The left rear brake rubs on my 96 lumina when the car has been setting awhile like in the morning. I have to go very slow, stopping several time before I exit the community where I live and the brake rubs and grates till I can get up to speed.... at least 25 mph, then they stop. After that, I can immediately slow down again and the brake is alright. Is there a vacumn hose related to the brakes? I've had the wheel off and there is wear on the top of the shoes. I adjust the brakes and they are alright for about a week only. The car has 29 thousand miles on it and this has been ongoing since 20k.

[jeffcoslacker]

That's usually a trait of fluid contaminated shoes from a leaking wheel cylinder....see any wetness? Common on GM cylinders with some years.

[Johnniemccoy]

Originally Posted by jeffcoslacker

That's usually a trait of fluid contaminated shoes from a leaking wheel cylinder....see any wetness? Common on GM cylinders with some years.

No... everything is dry. Shoes in good shape except for wear at the very top.

[jeffcoslacker]

Heel wear means they are hitting the drum at an angle in stead of face-on, which will cause the forward shoe to drag if it's acute enough...there has to be a reason...usually under adjusted. You said you adjusted them but if the drums are really worn, there will be so much lip on them that it feels like they are tight when you put them on, but once seated, they are actually still quite far from the contact surface in the drum...is this a possibility?

You'd have to replace them, or have them machined to take the lip off, otherwise you could adjust them properly with the drums on from the back, but you'd never be able to remove the drums without adjusting them down because the shoes be sitting down in the area behind the lip when properly adjusted.....

Sometimes a sticking parking brake cable will cause one shoe to ride up off it's land and drag also...do they all seem to be pulled tightly against the center post, not one riding up or trying to stay out, is there?

[jeffcoslacker]

PS I missed that the car has such low mileage....I wonder if you don't have a wheel cylinder that is seizing until it gets warmed up a bit....

[Johnniemccoy]

Originally Posted by jeffcoslacker

PS I missed that the car has such low mileage....I wonder if you don't have a wheel cylinder that is seizing until it gets warmed up a bit....

Has to be something like that. I've adjusted them twice - once at 20k and again a few thousand miles after. Still doing it. I think I'll go with the wheel cylinder and see if that works. Thanks.

[richtazz]

The brakes used on these cars are famous for dust accumulation. For whatever reason, the dust doesn't escape the drum, and will cause creaking, groaning, and grabby brakes. If there was excessive brake dust when you removed the drum, the only soultion is to buy a high-end set of shoes that don't dust so much, and periodically remove and clean the drums out. the noise you are hearing is the brake dust being trapped between the drum and shoe, and as you get up to speed, it's thrown out and sticks at the end of the shoe friction material until the next time you stop for a while, starting the whole cycle again.

[twistedtech]

This goes way back.I had a Celeb wagon or something of the sort come in and the rears would lock up cold.Only cold.New shoes,hardware kit,cut the drums,adj and adj and adj,still locked up cold.So I called a buddy of mine that was not your everyday Midas guy and asked him.He said "Change the wheel cyls",I asked why and he said don't he didn't know,just do it.So I did.I have done so from that point on,fixes the issue.Never did find out why,I just do.You change the w/cyls it will stop doing it.