Chi-Town Lite Foot

I've got a 95.5 S6.

After it sat on the driveway for about 8 hours on Saturday, I had backed it into the garage (about twenty feet). That took all of about 2 minutes. I got up Sunday A.M. to find a puddle of hydraulic fluid under the car. I look on the driveway and there was no trace of fluid. I popped the hood to find the fluid coming out the top of the hydraulic resevoir cap where the float needle extends out of the cap. The car was not running but the resevoir was completely full and the back pressure continued to push the fluid out. The fluid in the resevoir was at the top mark of the resevoir prior to this problem.

Does anyone have any idea what might be causing this?

Thanks.

scarman

Two areas that can change the fluid level are the steering rack and the brake accumulator.

If you stop with the wheels turned, the rack will hold more or less fluid, depending on direction.

If the check valve does not hold system pressure when the engine is shut off, the fluid in the brake accumulator will return to the reservoir. If the brake booster leaks pressure internally, it will deplete the accumulator and return that fluid to the reservoir also.

In either case, if the reservoir is full or overfilled when the maximum amount of fluid is in the rack and/or accumulator, it will be overflowing when that fluid is returned to the reservoir. I think there is a caution in the DIY section of the owners manual.

The check valve can malfunction if the fluid is dirty. It tends to turn black when the hoses deteriorate inside putting small pieces in the fluid. A better filter for the system and routine fluid changes are a good idea for the hydraulic system since it powers two important and expensive systems.

a911sc

Did you add fluid to the reservior recently?

The brake accumulator (AKA Bomb) has a check valve that basically holds pressure when the car is off. If this check valve goes bad the fluid from tne bomb will get pushed back into the reservoir. Sometimes the brake light will come on when first started until the pressure builds up.

You can either replace the bomb or just remove some fluid from the reservior.

Chi-Town Lite Foot

Thanks for the insight. The week prior, after the car sat overnight, I would start the car in the A.M. and find the brake pedal to feel like a rock. After depressing the pedal a couple of times it felt normal. I thought the master cylinder was going bad.

Any idea if the OME bombs are still available for this model?

Thanks.

scarman

Yes they are available through most online sellers. Dave Kase also runs a recharging service.

http://sites.google.com/site/audicqturbo/audibomb

Chi-Town Lite Foot

Thanks Tom

scarman

This looks like the cheapest if you go new. These folks are good to deal with and generally answer the phone as well if you have questions. This may be a Meyle unit, where I would prefer Febi-Bilstein, but maybe not at the price difference. : > ) For what some others are asking I would buy the dealer part - you get a 12 month part warranty there.

http://www.germanautoparts.com/Audi/S6/Brake/269/1