Rear brake troubles, Why do they keep locking ? Options

[Thor]

Hello to everyone at 914world.com. I am a new member from Belgium and ready to post my first question ...

Fase 1: Summer of 2003 ... during a saturday afternoon trip, I suddenly felt that when rolling to a stop the car balanced diagonnaly. At a stop I got a burning smell going through my nose and soon discovered the rear left break was smoking and running terribly hot. I got the car home and my mechanic unlocked the brake.

Fase 2: While passing the annual technical control, the mechanic said there was still an imbalance between the rear brakes. So back to the shop (another - VW-Audi based) where I was told the brake pads were gone and they replaced them.

Fase 3: During an orientation rallye in november 2004 the rear brakes started to squeal and the burning smell was back. This time the right rear brake started to lock. A quick repair in a garage where some young mechanics wanted to have a look at it put us back on the road. We had some good moments but at some stops the right brake would still feel hotter then it's supposed to be.

Anyone an idea of what could be wrong ? Calipers are supposed to be replaced before I purchased the car.
What can I do to restore the balance and keep them from locking ?

Thanks guy's ! (IMG:http://www.914world.com/bbs2/html/emoticons/beerchug.gif)

[Eric_Shea]

QUOTE

Venting clearance: I must be honest ... never heared about it. If it's to close would the brakes lock up on one side only ? I'll check this when replacing the lines.

I would replace with factory rubber lines. Cap'n Krusty likes Stainless Lines for sure! (IMG:http://www.914world.com/bbs2/html/emoticons/w00t.gif)

Yes the venting clearance would cause the brake to lock up on one side only, the side that is not adjusted properly. You have two adjusters an "inner" marked (I) and an "outer" marked (O)

(I) (O)
--| || |-- <---------Adjusters
----||
----||
----||||-
----|||| <---------- Rotor
----||||-
----||
----||
----||

They both operate with a 4mm hex wrench. The outer adjuster has a 13mm lock nut on it. Loosen the 13mm nut before you begin to adjust. Use a feeler gauge and set the clearance of the pad to rotor at .004. Do this by removing the parking brake cable. Then turn the outer adjuster "counter clockwise" to move the piston and pad toward the rotor. The inner adjuster will have a cover that probably has a 4mm hex slot in it. You need to go through the access hole on the control arm to get to it. Remove this cover and you will access the 4mm adjuster. Again, set the pad to rotor clearance to .004. This time the adjuster will turn "clockwise" to get the pad closer to the rotor. Once you have the clearance set, reinstall the parking brake cable.

If you have drilled rotors they may be "irregular". Spin them to make sure they're not hitting the pads once you've set the clearance. If they are, this is probably your problem. Make sure the mounting surface on your hubs is clean as well. You may have a piece of rust (what's that?) or other misc. item under the rotor causing a slight wobble. The rubbing on the pads can cause heat and heat can cause a lock up on that side.

My guess is those two things (new lines and venting clearance) will solve the mystery. If not... rebuild.