symptoms of a bad bomb vs. a bad mc

Bisqueth · 06-07-2006, 01:22 PM

i know, i know, i know...i'm shooting myself in the foot (ouch!), but this brakes getting hard and sticking question had me torn all usunder, so i got weak and took it to the dealer [morong, falmouth, me...more-wrong]
several of you excellent list folk have said "master cylinder! master cylinder!" [which morong said would cost me $550]
they, however, say "it's the bomb! it's the bomb!" to the tune of around $660. ouch.
so my question to the list: what are the differences in the symptoms of a bad bomb vs a bad mc?

Kneale Brownson · 06-07-2006, 02:39 PM

Symptoms of a bad bomb are that the brake light flashes when you step on the brakes. When you turn off the engine (after running it for at least a bit) and immediately start pumping the brakes, you should feel the pedal become harder to push than when the engine is running. If it's immediately after shutdown or just a few pumps, the bomb is dead. If you get maybe 10 pumps, the bomb is dying. If it takes 30 or more pumps for the pedal to become hard to push, you have a good bomb.

The MC failure symptoms include squishy brake pedal, with pedal going to the floor if pressed steadily. Another is the brakes seize up (at the wheels) when the MC is hot from heat under the hood and then release when you pour cold water over the hot MC.

A bad bomb does not cause the brakes to seize.

itsav8 · 06-07-2006, 06:14 PM

Hey whats wrong with Morong Audi in Falmouth? I got(well my Dad) bought me my 1st Audi from them back in 87! & there still around now? Must be OK.

But Kneale pretty much said all there is to say.
Sept if you need a new MC I have one FS. Shoot me a mail. & recharged "Bombs" can be had from Dave Kase for under $100. He adverts on the audifans marketplace. Or I could shoot you his mail addy.
Let me know.
Thanx
Ron
90 80q 20vt AAN project
90 V8q 3.6 not stock
93 V8q 4.2 "The Green Monster"

paulfern2000 · 06-07-2006, 10:57 PM

200Q20v · 06-08-2006, 03:01 AM

most of the techs trained on these cars have probably gone off to start their own businesses. The guys still working in the shop today are probably young and have little to no experience on the older cars.

just my .02 cents

SteveJ_in_TX · 06-08-2006, 04:38 PM

Also I seem to remember having seen an ad from our friend Paul on Audifans in the last day or so saying he had some OE bombs for sale for cheap.

Having said that, I will go wait by the door for the FBI to arrive.

("Hi gentlemen, want to see my Audi? The bomb on it is old but functional. Want some ice tea?")

06-07-2006, 02:39 PM	#2
Kneale Brownson AudiWorld Super User Garage is empty, add now Join Date: Apr 2003 Location: Full-time Coloradoan now Posts: 3,337	Re: symptoms of a bad bomb vs. a bad mc Symptoms of a bad bomb are that the brake light flashes when you step on the brakes. When you turn off the engine (after running it for at least a bit) and immediately start pumping the brakes, you should feel the pedal become harder to push than when the engine is running. If it's immediately after shutdown or just a few pumps, the bomb is dead. If you get maybe 10 pumps, the bomb is dying. If it takes 30 or more pumps for the pedal to become hard to push, you have a good bomb. The MC failure symptoms include squishy brake pedal, with pedal going to the floor if pressed steadily. Another is the brakes seize up (at the wheels) when the MC is hot from heat under the hood and then release when you pour cold water over the hot MC. A bad bomb does not cause the brakes to seize.

06-07-2006, 06:14 PM	#3
itsav8 AudiWorld Super User Garage is empty, add now Join Date: Jan 2004 Posts: 3,097	Re: symptoms of a bad bomb vs. a bad mc Hey whats wrong with Morong Audi in Falmouth? I got(well my Dad) bought me my 1st Audi from them back in 87! & there still around now? Must be OK. But Kneale pretty much said all there is to say. Sept if you need a new MC I have one FS. Shoot me a mail. & recharged "Bombs" can be had from Dave Kase for under $100. He adverts on the audifans marketplace. Or I could shoot you his mail addy. Let me know. Thanx Ron 90 80q 20vt AAN project 90 V8q 3.6 not stock 93 V8q 4.2 "The Green Monster" __________________ thanx Ron 2.6l 20vt stroker motor W/O a roof 91 V8 5sp mit 4.2 aka Black Betty 91 200 20v 22psi 90 v8q 3.6 not stock...gone but not forgoten :-(

06-07-2006, 10:57 PM	#4
paulfern2000 AudiWorld Senior Member Garage is empty, add now Join Date: Mar 2002 Posts: 784	Check Audifans market place for bomb...maybe interesting. __________________ Paul Fernandes luxembourg-Europe 1991- Audi V8 5 speed 1991- Audi 100-C4(everyday car) 1990- Audi 100 avant sport quattro turbo 1990- Audi 100 avant quattro (in restoration)

06-08-2006, 03:01 AM	#5
200Q20v AudiWorld Member Garage is empty, add now Join Date: Nov 2000 Posts: 560	beware of dealer mechanics.. most of the techs trained on these cars have probably gone off to start their own businesses. The guys still working in the shop today are probably young and have little to no experience on the older cars. just my .02 cents

06-08-2006, 04:38 PM	#6
SteveJ_in_TX AudiWorld Senior Member Garage is empty, add now Join Date: Dec 2000 Posts: 1,746	^^^^^ Agree with Kneale Also I seem to remember having seen an ad from our friend Paul on Audifans in the last day or so saying he had some OE bombs for sale for cheap. Having said that, I will go wait by the door for the FBI to arrive. ("Hi gentlemen, want to see my Audi? The bomb on it is old but functional. Want some ice tea?") __________________ -Steve Jensen 87 5kcstq

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