GeorgePBurdell

This is a long story, but I have been plagued with an intermittent dragging front brake situation on my '85 CGT. The front brake peday would occassionally "build up" to the point where the pedal would become "solid" and the front brakes would drag. You could smell the hot brakes and the car would not roll freely when stopped. If I continued to drive the car - I sometimes wasn't where I could park and leave it - after a period of time, the pedal would return to normal and the car would be fine for an indeteminate period. If I parked the car for more than a few hours - before the pedal returned to normal - it would work properly when I returned to the vehicle after 2-3 hours.

Having had a similar problem with some old Yamaha motocycles that are prone to "locking" disk brakes, I pulled the front calipers apart and cleaned them, replacing the seals. Found some black "gunk" in the right front caliper, and while this helped, the problem remained. Again, following motorcycle experience, I replaced the front brake hoses - these will occaisionally deteriorate on bikes and the inner lining will flake and form what is essentially a check valve, causing very similar problems. This seemed to really help - the car has been fine for almost two weeks of daily driving. Today, coming home from a job site, the dragging is back! Much less severe, but enough to smell and feel and to raise the pedal from its normal engagement point. It "cleared" itself while driving, but I need to fix this - I don't like untrustworthy brakes and there is obviously something wrong here!

In summary - new brake caliper seals and cleaned caliper assemblies and pistons; new front brake hoses; probably three pints or more of brake fluid flushed through the system - in both directions. Only thing left unmolested is the master cyclinder.

Any ideas/suggestions welcome.

Jeff Rees
'85 CGT

StormChaser404

I was goona say Master Cylinder as soon as you mentioned the pedal would become "solid" and at the bottom you also said it's the only part not replaced/rebuilt...

AudiCGTSB

Slightly sinking pedal when I was on an incline. You rs sounds like it could be the vacuum "pumpkin" the black cylindrical looking thing behind the MC. I have heard of people getting a really hard pedal from a bad pumpkin but I never expirienced this first hand.

GeorgePBurdell

I appreciate the feedback - as the MC is the only thing in the system NOT replaced, I too suspect it. Just have never run into this sort of a problem before.

Any advice/suggestions on the replacement?

Jeff Rees
'85 CGT

DBF

...r&red or refurbished everything else but the MC.
I wanted to chime in and tell a little dit on my hard pedal with my coupe and what the cause was. While I was experiencing the electrical woes for the past 1.5 years, I haven't had the opportunity to drive the car much. I wasn't worried about getting stranded, I just didn't want anything to short out and fry the poor old girl. Therefore, in the past 1.5 years I've only driven the car approx 5000 kms. Over that time, I noticed the brake pedal getting progressively stiffer. I had no issues with dragging (initially) or a reduction in braking. Last week the drivers rear started to drag. After a closer look, I realized that the after piston on the left wheel cylinder was not working (I refused to say siezed!!). So, after a little gentle persuasion, I managed to get everything working again. I used my new power bleeder and bled about 1.5 liters through the cylinder. I will change both cylinders, shoes, bearings, spring kit ect as time permits.

AudiCGTSB

<ul><li><a href="https://forums.audiworld.com/4000/msgs/13618.phtml">clicky</a></li></ul>

GeorgePBurdell

While related, this isn't my problem. I have no problem with the brake perfromance - and it NEVER needs extra effort, nor sinks to the floor - actually the opposite happens. The pedal engagement point just "rises" until the brakes are slightly engaged at all times. The drag creates considerable heat (to be expected) until, for no apparent reason, things return to normal. The problem can be temprarily "cured" by simply parking the car - or by continuing to drive, if necessary, until it resolves itself.

Jeff Rees
'85 CGT