Pokechop

Ok, did a search and I'm not sure where to go with this. With the VERY cold weather here in the NE I find that when the temp gets below 20degF my brake pedal becomes very marginal. I get some minimal braking at the top of the travel and as I press further I get little additional braking. I can NOT get the ABS to engage (on my snowy driveway) when this is happening.

As the ambient temperature climbs the brakes improve until they are normal. Actually one day I was driving when the pedal seemed to "crunch" and go from marginal braking to normal braking. So I suspect some water in the system somewhere. My mechanic bled the entire system (he's a porsche/Merc guy and works mainly on German cars but is a bit old school) which did NOT alleviate the problem. Maybe something in master cyl or even the ABS system got moisture in it?

Anyone experienced this. My good old 2000 A4 now has 300,000 miles and still going pretty strong and I need to get this remedied. Thanks for your help.

flc

What kind of pads are you using?

I recently installed EBC Red Stuff, and I noticed that in the very early colder morning, I almost need to press the pedal all the way to the ground while backing out of my driveway for the first 15-20 feet. Didn't happen on my older pads... Once I drive down the street, they are fine and have a bigger bite than my previous pads after they've seemed to have warmed up... I bled my brake system, so I don't think it was that.

Pokechop

last winter's cold spells, and indeed may have been through a couple of winters now. Not that I know what my mechanic is using. Pretty sure they'd be whatever Audi would use. Hmmmmmm...

tjf

Way back there was a tsb. I remember they modified something with the booster to eliminate a cold weather problem that resulted in reduced boost. I'm not sure exactly what was done though.
I never had that problem, but I do have the wet weather issue.