Binding Brakes Help

[daz635]

Hi All

I have an issue at the moment with the brakes binding on when they get hot. The car is a RHD so heat soak into the master cylinder is a problem

It only occurs when the car has been run for a while in traffic and then has to idle for a period so I am sure that it is related to under bonnet temperature. The symptoms present
as if the master cylinder is sticking and closing partially one of the ports to the front brakes slightly ie no pedal feel than a a definite click. However the master cylinder was replaced 8 months ago and my mechanic has just flushed the system and checked all the seals 2 weeks ago. No issues on the highway or when the car is cool only when the under bonnet temperature creeps up

The car had badly binding brakes before I bought it and changing the master cylinder seemed to fix the problem. Is there anything other than heat that would cause the master cylinder not to fully release when hot ie the brake booster. When I let the car cool down for 30 minutes or so the brakes are perfect again

Has anyone head of having the heat soak issue with new master cylinders and how did you solve the problem.

Thanks

[GazM3]

The master is on the RHS yeah?

Anyway if u have replaced your master it could be a sticking caliper (if one of the wheels is dusty it's a telltale sign). I had same problem on my 735 e23 and it turned out to be a twisted brake line on the front left. Untwisted it and all good.

If your brake booster is on the left it could be the adjustment in the brake bar or the brake bar itself runs pretty close to the glovebox lip so have a look at that. If it's on the RHS yes a heat shield would be in order especially if the exhaust doesn't have one.

[daz635]

Thanks Gaz

The master cylinder is on the RHS so I may look at some sort of heat shield over the exhaust manifold

I am thinking that the rod between the brake pedal and the booster is out of adjustment. This can cause a preload thru the brakes when the pressure is high enough.

Have checked the callipers and the lines and all look good

[JCS]

DAZ,

Check you brake shackle length.

http://www.bigcoupe.com/phpBB2/viewtopi ... 17&t=16351

Best,

[daz635]

Well I have finally cured my binding brake issue

The booster was rebuilt with a seal kit from JCS thanks Jay and the master cylinder was replaced with a new unit from ATE

I have purchased some heat shield material to make a heat shield for the new master cylinder

After extensive testing the binding issue has not occurred again.

Thanks All