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Audi A4 B8: Why is There a Loud Clunk When Braking/Going in Reverse?

Is your Audi letting out a loud, annoying, and somewhat scary clunking noise when you apply the brakes in reverse? This article will help you track down the source of the noise and silence it for good.

By Brett Foote - April 7, 2016

This article applies to the Audi A4 B8.

We expect our cars, particularly those that are branded as "luxury" cars, to be (for the most part) quiet in their daily operation. Transmissions should shift smoothly and brakes should silently bring us to a halt. But for many A4 owners, this simply isn't the case. One of the more common issues that pops up with the B8 A4 is a loud and rather obnoxious clunking noise when applying the brakes in reverse gear. Owners report feeling a sensation akin to the front wheels refusing to turn and getting dragged along by the rear. If this sounds like the problem you're having, keep reading and we'll walk you through the diagnostic process.

Audi A4 B8: Why is There a Loud Clunk When Braking/Going in Reverse?

Materials Needed

  • Jack and jack stands
  • Socket set and ratchet
  • Pry bar

Step 1 – Check control arm bolts and bushings

Bad control arms and/or loose suspension bolts can cause a clunk.

First, jack the car up to take a look at your control arms and, particularly, the suspension bushings as well as bolts. Inspect your bushings to see if any are flattened, cracked, or broken and replace if necessary. Double check to make sure that all the bolts are torqued to factory spec and that they have the correct nuts on them. Some cars came from the factory with control arm bolts that were too large (same size as the ball joint nuts), leading to this issue. The correct part number for the lower control arm rear nuts is wht-001-987.

AUDI A4 B7 B8 THUNK CLUNK NOISE SUSPENSION BRAKE ISSUE PROBLEM
Figure 1. Loose and improperly sized control arm nuts are the most common cause of a clunk in reverse.

If your bolts are the correct size and are torqued to spec, move on to Step 2.

Step 2 – Check your brakes

They might be grabbing too aggressively.

Some owners have reported that their clunking problem comes from brake pads that grab the rotors too aggressively when the car is in reverse, causing them to move and generate a clunking noise. Have someone reverse the car and brake while you observe the pads and see how they lock up. If they move around while the brakes are applied, take them off and inspect them. Some pads have an over-sized lip that causes the issue. If this is the case with your brake pads, they might need to be replaced.

AUDI A4 B7 B8 THUNK CLUNK NOISE SUSPENSION BRAKE ISSUE PROBLEM
Figure 2. Check to see if your brake pads have an over-sized lip that could be grabbing the rotors too aggressively.

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