tobykinkle

Kinda confused...........I was installing a strut tower bar on my 1997 A4Q, and one of my friends was resting his hand on the brake reservoir when he heard a cracking. Part of the reservoir had chipped away (maybe the size of a dime). What was left was just the thin membrane. Its not leaking, and I ordered one from Audi, but just want to know what the hell caused it? It didn't look like there was any battery acid that got to it, and it doesn't get that hot behind there, so I was just confused...Anyone else have this problem?

AudiMick

They deteriorate over time and become brittle, probably a good thing you discovered it.

Next time you did a pressure bleed (even as low as 10 psi)it would probably have cracked and fluid would have gone everywhere.

Ask me how I know!

tobykinkle

So your saying age is the culprit? Just seems wierd.The sad thing is, the master cylinder looks brand new(looks newer then the ones I sell at my work). And why would it deteriorate that quickly? I mean, its twelve years old, but still, I have had older cars and the have never done it.

hellbringer

I had mine replaced as well, not due to a "so called" buddy resting his hands on it , anyways it was due to old age. ...also had my coolant reservoir replaced as well.. .I suspect it's engine heat & fluid temperature.