C3 Brakes seizing -help!

Ringmaster · 05-05-18, 06:36 PM

Hi folks!

Thought I'd take my C3 out for a spin in this lovely weather, as it hadn't been out for a couple of weeks.

I began to notice that it felt like something was holding it back. Then the brake pedal felt much firmer that I am used to. Just before I got home something seemed to go thud under the car somewhere, and all seemed back to normal.

The front discs were steaming hot. Rear discs were very hot too, but nothing like the front.
I don't think the problem has gone away.

Can both front calipers seize at the same time? They are original.

Any ideas please.....

Duffy3074 · 05-05-18, 06:53 PM

No way all seize at the same time, the rears especially do little work compared to the fronts.

My guess would be a sticky master cylinder or brake linkage.

You really would need to take it off to have a look at it, I’m assuming there’s no ABS or warning lights on the dash

John. · 05-05-18, 07:15 PM

As above I would think.....seized linkage or sticking master cylinder.
Does it have a vacuum servo or is it boosted via the PS pump?

Ringmaster · 05-05-18, 08:33 PM

No ABS.

Boosted by PAS pump.

What is the brake linkage?

John. · 06-05-18, 06:02 AM

Quote:

Originally Posted by Ringmaster

What is the brake linkage?

The mechanics between the pedal rubber and the master cylinder.

I had same problem on my coupe, I replaced the master cylinder to cure it.

Ringmaster · 06-05-18, 06:26 PM

Thanks chaps.....

From what you say it sounds like the master cylinder.

Wouldn't be unexpected for a 31 year old part I suppose......

Ringmaster · 26-05-18, 05:55 PM

Folks,

Finally got the C3 to my mechanic on Wednesday. He couldn't find anything wrong. It was behaving itself perfectly.

Took it for a spin in the sun an hour ago and the problem returned. I could feel the car being held back,then occasionally surge forward as the brakes freed up, then felt it held back again,

Front wheels boiling hot. Rear wheels not too warm, ok.

This time the brake pedal is travelling about 4 inches more before the brakes engage. The front calipers are definitely the only ones affected and they remain engaged. I guess that would explain the extra distance the brake pedal is travelling now.

I am going to get the master cylinder replaced regardless now. Before I do so, are there any further opinions from you all?

Duffy3074 · 26-05-18, 06:51 PM

It’d be my shout still

John. · 26-05-18, 06:54 PM

On my CQ the underbonnet temp gets pretty high I think.....and this is when my brakes would bind.
Does yours have a vacuum servo, if yes it would be easy enough to pull of the vacuum pipe when they're binding and see if they release ?.......if yes then servo not good. If you have vacuum servo!

Ben · 26-05-18, 08:32 PM

Quote:

Originally Posted by Duffy3074

It’d be my shout still

+1

Keep the old master cylinder and open it up to see.

05-05-18, 08:33 PM	#4
Ringmaster Senior Member Classic Audi Club Member Join Date: Apr 2008 Posts: 1,326	No ABS. Boosted by PAS pump. What is the brake linkage? Last edited by Ringmaster; 05-05-18 at 08:35 PM.

05-05-18, 06:53 PM	#2
Duffy3074 4 ring whore! Classic Audi Club Member Join Date: Aug 2015 Location: Dalgety Bay, Fife Posts: 2,078	No way all seize at the same time, the rears especially do little work compared to the fronts. My guess would be a sticky master cylinder or brake linkage. You really would need to take it off to have a look at it, I’m assuming there’s no ABS or warning lights on the dash

05-05-18, 07:15 PM	#3
John. 4 ring whore! Classic Audi Club Member Join Date: Mar 2011 Location: Scottish Borders. Posts: 7,520	As above I would think.....seized linkage or sticking master cylinder. Does it have a vacuum servo or is it boosted via the PS pump?

06-05-18, 06:26 PM	#6
Ringmaster Senior Member Classic Audi Club Member Join Date: Apr 2008 Posts: 1,326	Thanks chaps..... From what you say it sounds like the master cylinder. Wouldn't be unexpected for a 31 year old part I suppose......

26-05-18, 05:55 PM	#7
Ringmaster Senior Member Classic Audi Club Member Join Date: Apr 2008 Posts: 1,326	Folks, Finally got the C3 to my mechanic on Wednesday. He couldn't find anything wrong. It was behaving itself perfectly. Took it for a spin in the sun an hour ago and the problem returned. I could feel the car being held back,then occasionally surge forward as the brakes freed up, then felt it held back again, Front wheels boiling hot. Rear wheels not too warm, ok. This time the brake pedal is travelling about 4 inches more before the brakes engage. The front calipers are definitely the only ones affected and they remain engaged. I guess that would explain the extra distance the brake pedal is travelling now. I am going to get the master cylinder replaced regardless now. Before I do so, are there any further opinions from you all?

26-05-18, 06:51 PM	#8
Duffy3074 4 ring whore! Classic Audi Club Member Join Date: Aug 2015 Location: Dalgety Bay, Fife Posts: 2,078	It’d be my shout still

26-05-18, 06:54 PM	#9
John. 4 ring whore! Classic Audi Club Member Join Date: Mar 2011 Location: Scottish Borders. Posts: 7,520	On my CQ the underbonnet temp gets pretty high I think.....and this is when my brakes would bind. Does yours have a vacuum servo, if yes it would be easy enough to pull of the vacuum pipe when they're binding and see if they release ?.......if yes then servo not good. If you have vacuum servo!