DDQ

I took a 5 hour trip this weekend in the S4 ('01.5, 6 speed, and it has StopTechs with Pagid pads). Typically the car is fine, never had any issues with the brakes or anything, which have new slotted rotors and pads as of about 3,000 miles ago.

This is the first time I took the car for a trip this long. After driving for about an hour, all of the sudden the car starts vibrating like crazy. It gets more intense, and the car is shuddering to the point where I have to pull over. Feels like I have two flat tires, although the car is not pulling at all. After I stop for a minute, and check all the tires and rims, I see nothing wrong. Get back on the highway, and the problem is completely gone.

Then about an hour later, same thing happens. I pull over, and the problem is gone again. Then I drove the next 3 hours with zero problems, and drove around town all weekend with nothing wrong.

Then I get back on the highway. After about an hour, the same problem comes back. Pull over, goes away again. Then I drove 4 more hours and the car was completely fine.

So, I'm quite sure this is some sort of problem with the brakes, but I just can't figure out what it is. Has anyone had anything like this? Any ideas what it could be?

Hal_TT::CBP

Do you have aftermarket wheels? Check your wheel bolts.

Sawbones

Vibration under braking may be due to deposits. Rebed the brakes.

Vibration when driving couild be many things.
wheel bearing
loose lugs
wheel out of balance
etc.

However since it seems sporadic I'm really not sure...

JasonS4+Festicle

was it raining? what kind of rims do you have? recently taken the wheels off for anything?

k04/rs6north

do you have cpp adjust front links?

DDQ

The vibration was when i was driving, and when braking, it didn't matter which. It only went away after coming to a complete stop.

I have 18" SSR Comps. I initially thought that it could be a wheel out of balance, but the fact that the problem would go away after I stopped, it didn't add up.

None of it really adds up. I'm think it might have something to do with when the brakes heat up, and the caliper piston gets stuck. Because it only happens when I drove for about an hour. I drive on the highway to work about 20 minutes everyday, and this has never happened. But both times I took the car on a long trip, it occurred about 1 hour into it. But finally it would be gone for the last few hours of the trip, which is the part that doesn't make sense to me.

But, it is not causing the car to pull to either side. Which seems odd to me. That is why I thought it might be something with the ABS or ESP.

Thanks for the help fellas.

Stätus Josh

is if you were really braking hard over and over, and if you are on a long trip you likely are actually not using the brakes much.

DDQ

Agree. But I thought maybe at high speeds pad friction from a stuck caliper could cause it.