Wasn't really sure how to title this problem let alone words to search for previous post, so here goes trying to describe it:

Interested to know if anyone experiences the same and suggestions as to what to do. Here is the scenario:

2010 A4 2.0T Quat'ro
1.) Drive forward for a while.
2.) Stop.
3.) Reverse then apply brake to slow or stop reversing.
4.) Under-carriage feels like it shifts and sort of slams as the brake applies.
5.) Subsequently applying the brake does not repeat the issue until after again driving forward for a while.
6.) Issue does not exists if reversing from a stopped position.

Weird, but that's the best I can explain it. Anyone have any thoughts? Dealer said they didn't feel anything and said the brake pads were very low. But I still wouldn't expect that type of issue just from pads being low. So I'll try another dealer.

 

I don't know if this will shed any light for you, but I just had a repair done for another issue, and soon after my car began making a pretty forceful slam/knock noise when I go into reverse. It's not across-the-board consistent, but I get it at least once a day.

Prior to that I had a steering jitter issue while parallel parking, and no slam. Dealer replaced the power steering hose, and now the car slams. The feeling is almost the same as when a transmission is low on fluid and goes into gear with a bump. My A4 is an automatic, by the way.

Issue isn't resolved yet...I'll let you know what the dealer says after I take it in.

 

Thanks for the reply AvantNoob.

I think there may be a difference in what you experience because you said "slam/knock noise when I go into reverse". My problem occurs after rolling in reverse and stepping on the brake. And again, this only happens if the car has been driving forward for a little while, then stop, go into reverse and step on the brake after reversing.

Maybe related though so thanks again & good luck. (I haven't made it to another dealer yet for their analysis)

 

I think the rear subframe has bad bushings and it's preloaded for forward motion since that's the usual direction of travel. Then when you go in reverse and then hit the brakes you've got momentum and the weight of the car body applying forces to many things, including the bushings in the subframe. If a bushing is bad you'll get a clunking noise. It could also be a control arm. The strange thing is you don't hear it when you go from reverse to forward, where those bushings would shift on you again, making noise.

 

Bad Bushings Jeff? The car only has 40K miles on it. (2010) Could bushings be bad already?

Anyhow, thanks for the thought.

 

You bring up a good point with age and mileage. If this was front suspension I'd say maybe, if the bushing or bushings had an oil leak on top of them. That isn't going to happen on a rear subframe though. Only other thing I could think of relating to bushings would be accident or lots of potholes taking their toll on them.

 

i think i have the exact same problem as mmediaman, i have a 2009 a4 3.2 quattro, and even if i just tap the brake in the slightest gonig in reverse after being in forward i will get a big thump sounding like i just ran over a chiwawa dog. were you able to find the problem mmediaman? i just got my car back from a week of them looking and they didnt fix it yet, i have to take it in again.

thanks

 

I was also thinking about the sub frame bushings and perhaps a loose mounting bolt. Also to consider is the brake pads which may have too much clearance between the abutments and moving back and forth with the disk until they slam into the abutment.

 

Yes cbrandt, I did get it fixed!

I posted the entire solution in another forum and I can't say I can easily find that post at the moment.

The problem was due to the front brake mechanism.

There was some sort of mechanism that didn't work too well because of the brake wear and so because it was getting close to brake replacement time, when the dealer went to replace the brakes, discovered that is where the reverse slam was coming from. Pretty amazing.

If you really need the detail, post back. But I think if you tell your dealer it has been know to come from the front brake mechanism, they should be able to find it.

 

much appreciated, i have my 3rd appointment for this problem on Monday so ill let them know and see how it goes from there.
thanks again.