could this be a bomb?

Crossle · 06-07-16, 07:54 PM

Just looking at buying a 2.3 B3 20V coupe but being put off a bit as seller says front brakes are sticking and he has tried discs and pads. It's something that comes in once heat gets into them apparently. Guy said he thinks it might be the bomb? My experience tells me it's not a symptom of a bomb. Any ideas?

Just not too sure if to go and buy it this weekend or not now as I have had experience with these brake systems costing me a lot of money in the past.

Hanuman · 06-07-16, 08:07 PM

Sounds very similar to failing master cylinders which have been a source of long debate on the UR.

A failed 'bomb' (which is of no relevance to the chaps in the listening rooms) is often evidenced by a lack of braking effort by the car/more braking effort by the operator/frequent warnings and red brake symbols.

Master cylinders don't cost a huge amount, and take about an hour or so to fit, bleed, etc, assume that all else is working well.

fourringsrus · 07-07-16, 05:40 PM

I would be looking at sticky callipers, the sliding pins get manky and rusty if neglected and cause grabbing, sticking, no braking on one side at random and of course overheating once stuck in contact between pad and disc, worth a look

Stuart

bazburn · 07-07-16, 06:02 PM

Just had this exact same prob on my 90Q 20v and it was the master cylinder.....can also be flexi's caving in too.....

jimh · 07-07-16, 06:21 PM

If it starts off ok, then gradually applies the brakes harder as it heats up, until the car is undriveable until it cools down, that's the exact symptom of failing master cylinder.

No one has been able to explain it, and it doesn't appear to make sense, but I have seen it happen (and get fixed) many times on Ur quattros.

Bugmaster · 07-07-16, 06:34 PM

Hi All

I replaced my brake master cylinder on my ur last year with exactly those symptoms, hard to brake, pedal getting harder and the brakes getting very warm. After half hour of rest the brakes were fine again.

I got my cylinder from Pete Reeve.

Regards

Crossle · 07-07-16, 08:49 PM

Spot on chaps, that's what I wanted to hear, I've just bought the car, pick it up tomorrow.

Anyone got an idea of where best to buy? It's a 5 cylinder 2.3 1990 20v 4WD coupe

bazburn · 08-07-16, 09:14 AM

Quattro Corner ( Pete Reeve ) , Eurocarparts, TPS, pretty common part I think...

06-07-16, 08:07 PM	#2
Hanuman Trickster Classic Audi Club Member Join Date: May 2009 Location: Heckling from the cheap seats, Phnom Penh, KoW Posts: 7,020	Sounds very similar to failing master cylinders which have been a source of long debate on the UR. A failed 'bomb' (which is of no relevance to the chaps in the listening rooms) is often evidenced by a lack of braking effort by the car/more braking effort by the operator/frequent warnings and red brake symbols. Master cylinders don't cost a huge amount, and take about an hour or so to fit, bleed, etc, assume that all else is working well. __________________ I wish they would keep the damned Chinese away now that I can go home, so that I can enjoy Fish amok and a draught Angkor

07-07-16, 08:49 PM	#7
Crossle Grown up member Classic Audi Club Member Join Date: Jul 2015 Location: northampton Posts: 266	Spot on chaps, that's what I wanted to hear, I've just bought the car, pick it up tomorrow. Anyone got an idea of where best to buy? It's a 5 cylinder 2.3 1990 20v 4WD coupe Last edited by Crossle; 08-07-16 at 05:52 AM.

07-07-16, 05:40 PM	#3
fourringsrus Grown up member Join Date: Feb 2011 Location: Ashford Kent Posts: 468	I would be looking at sticky callipers, the sliding pins get manky and rusty if neglected and cause grabbing, sticking, no braking on one side at random and of course overheating once stuck in contact between pad and disc, worth a look Stuart

07-07-16, 06:02 PM	#4
bazburn Grown up member Classic Audi Club Member Join Date: Apr 2010 Posts: 273	Just had this exact same prob on my 90Q 20v and it was the master cylinder.....can also be flexi's caving in too.....

07-07-16, 06:21 PM	#5
jimh Grown up member Classic Audi Club Member Join Date: Dec 2008 Posts: 122	If it starts off ok, then gradually applies the brakes harder as it heats up, until the car is undriveable until it cools down, that's the exact symptom of failing master cylinder. No one has been able to explain it, and it doesn't appear to make sense, but I have seen it happen (and get fixed) many times on Ur quattros.

07-07-16, 06:34 PM	#6
Bugmaster Grown up member Join Date: Jan 2010 Location: Devon/Cornwall Posts: 176	Hi All I replaced my brake master cylinder on my ur last year with exactly those symptoms, hard to brake, pedal getting harder and the brakes getting very warm. After half hour of rest the brakes were fine again. I got my cylinder from Pete Reeve. Regards

08-07-16, 09:14 AM	#8
bazburn Grown up member Classic Audi Club Member Join Date: Apr 2010 Posts: 273	Quattro Corner ( Pete Reeve ) , Eurocarparts, TPS, pretty common part I think...