Godot

I have a 1999.5 A4 2.8 Quattro. The brakes have started to make an intermittent pulsating noise. It does not seem to be the ABS. My mechanic (who services Porsche's) tells me that the brakes are fine and that the diagnostic check does not uncover any other problems- he tells me that it is not uncommon for high end vehicles like Audis and Porshce's to experience this problem with wet conditions that creates some brake or emergency brake rusting. I have seen some reports about this condition. Does anyone know of a permanent solution to this problem?

RKA

Usually a result of warped rotors, or improperly torqued lug bolts.

Ray Calvo

I would expect that any shop could diagnose this problem, and my thoughts would be it's rotors also (moderate braking you get vibration; disappears when take foot off the pedal?). His feeling that it's "normal" bothers me; whenever my Porsches (owned one or other 911 since 1976) or other cars exhibited this, new rotors cured it. Then again he's not trying to fleece you.

Take a careful look at the rotor. Do you have discoloration around the circumference? Another indication of warped rotors.

laxkid

it doesnt happen all the time but happens ever couple days. When i stop and come to a complete stop either the front or back of my car makes like a putting noise. Very confusing, the dealership cant figure it out cause it doesnt happen when they drive it. Anybody know what this could be, it come from the center up front and back, never front and back at the same time either front of back...help!

Godot

I've been satisfied with their service of my Audis over the last few years - it was a perfect opportunity for them to do unnecessary work on my rotors, if they wanted to. The noise started a few weeks after my snow tires were mounted - maybe it is the lugnuts, although I suspect the tires came off when they checked the rotors and pads.

Reggie

but it is not normal and you are right to be concerned.

Some cars can get warped rotors from improperly installed and torqued wheels. SHOs were notorious for this

RKA

If the wheel bolts aren't torqued to the same degree all around, the rotor will warp when it heats up under moderate or hard braking. If you haven't punished your braking system since the snows were installed, odds are, loosening all the bolts, and re-torqueing them to spec will cure the problem. My guess is, you'll find a few bolts that are really really tight on a few wheels, and a few on the same wheel that aren't as tight.

My advice...get yourself a torque wrench from Home Depot ($65). Set it to 89 ft-lbs, unscrew each bolt 1 full turn (use a breaker bar, not the torque wrench), then torque the bolt to 89 ft lbs.

Yes, $65 is a lot of money...but I would advise everyone to hand torque their bolts after the garage is done doing their work. It prevents a lot of headaches with warped rotors.

Reggie

<center><img src="http://www.harborfreight.com/cpi/photos/00200-00299/00239.gif"></center><p>I got mine for 14 on sale

Had the accuracy tested and it was off by 0.1% - which is extremely accurate.

RKA

:-P

Reggie

but their case is black.