Oh Deer! (new bomb?)

[johne]

Does the new bomb cure the "beeps" 30 seconds after start up. I get this 90% of the time when I first start my car...

No, not necessarily. The bomb is just an energy rerservoir just like the vacuum tank on a conventional brake servo.

All bombs left for a period of time will slowly leak away their stored pressure but new ones take longer than old ones so if you replace your bomb you'll be able to leave the car longer before you get the "!" warning after 30 seconds but you'll still get it eventually, it just may be only after months of no use with a new bomb.

You get the "!" warning because it's taking your hydraulic (PS) pump more than 30 seconds after start-up to refill the bomb so it's back up full of energy in the form of stored hydraulic pressure to assist your brakes. When your pump gets old it takes longer to refill the bomb especially if you're using the PS at the same time, i.e. manouvering the car off your drive. However, as the "!" warning does go off and as long as it doesn't come on again, then the system is fine. If Audi had set the time limit to 1 minute rather than 30 seconds most folks would never see the "!" warning and the bomb wouldn't get the bad rap it does.

The test of how many brake pushes you can do before the pedal goes hard measures how much energy the bomb can store. That's the one that counts. As long as the bomb can store enough energy to work your brakes, that's what matters, not if the "!" comes on after 30 seconds and then never comes on again.

John

[Error404]

Likewise if the servo is going bad it slows or even prevents the buildup of hydraulic pressure and so you get the warning for that also
As Johne says you only need to worry really if you get the warning after the first couple minutes of running.

The bomb does reduce braking force though as its loses pressure, because is starts to act like a pressure damper, absorbing some of your pedal force, meaning you need to push the pedal harder to slow down as much. I'd have thought there was a check valve in there, but if so they must be a common failure

[bungle74]

OK, mine is now doing this randomly, sometimes (!) flashes constantly other times not at all, sometimes it comes on and off at various points with no rhyme or reason. I get well over 40 pumps doing the pump test and the fluid is up to the Max level so wonder if this is down to the fluid cap needing to be cleaned.

What is the correct thing to clean it with or will an old toothbrush do the trick? I haven't taken the cap off yet it's been too dark after work and want to make sure I don't break anything.

Cheers

Lee

[fourwh33ldriv3]

Mine is hard from the word go. Is that good?

That is good...but then it also means you're just too bloody horny...

[JonJon 2.2]

I just bought a new bomb from Febi. I have a 3B and the partnumber on the old bomb is 893612061A, according to the Norwegian Audi dealer the partnumber was changed to 893612061C in 1992. Before I orded the bomb I had a good look in the ETKA.

Early coupe Quattro / S2-3B up to 8B-L-06900 have 893612061C. The Febi partnumber:26537.
After 8B-L-6900 have the partnumber 4A0612061D. The Febi partnumber:26538.

Audi 100-200/Avant Quattro have 857612061C. The Febi partnumber:14178. Banto treadsize M12x1,5
But Audi 100- 200/avant Quattro also have bomb with the partnumber 443612061H, Febi partnumber 14176. Banto treadsize M10x1.

80 avant RS2 have 4A0612061D up to 8C-S-000368, and from 8C-S-000369 >>it is 8A0612061. This information was for LHD, I don't know partnumber for RHD, sorry guys.

Coupe 8B without Quattro have 4A0612061D.

Audi Quattro / sport 85. Have 893612061C F>> 85-K-020 000. And 4A0612061D F 85-L-000 001>>.

Please correct me if something is wrong, and always check the partnumber on the old bomb.

Cheers