A4 B8 problem during braking

[eprodwow]

Hello, i have a problem with my a4 b8 3.0tdi 2008. Some time ago i noticed steering wheel vibrations and wobble/rattle sound when i was braking from +- 140km/h (86mph). It only happens when i brake harder. I thought it is because of warped rotors, so i bought new brake rotors and pads, right control arm and bowl joints were bad so i replaced it also + i got new tires+balance+wheels realignment.
But it didn't help, not sure what to do next, i'm thinking about maybe wheel bearing or wheel hub, but i'm not sure.
Have anyone experienced a similar problem? Thanks for any help.

 

[spartacus68]

Could be a multitude of things. The wheel bearing is a possibility, but you'd normally hear a drone sound if it was on the way out. It's a bit of pain by all accounts if it's not been changed before. Check out Dave Sterl's channel for the how to change it. You could diagnose with the discs and pads off the see if there's a rumble on the bearing. One tip is to jack the car and spin the wheel and hold onto the coil spring for tell tale vibration. Unusual to get lateral play unless it's particularly bad.

Look at the suspension again. That's tie-rods, including inner and outer, the upper control arms and the lower arms, also ARB bushes. Also look at the suspension top mounts too. Useful video here:

Hope you get it sorted.

 

[DarthVAG]

i had similar issues start about 1-2 months ago on my 2010 2.0TDI a4B8. It started as random steering wheel vibrations, couldn't really define a specific speed it was happening at, as sometimes it was at 80kmh, other times at 120kmh. It then squealed occasionally for short periods of time, so I thought it may be stuck slide pins and possible pads touching on the discs whilst driving causing the vibrations - but the wheels/rims and parts were not getting hot so it wasn't stuck slide pins etc.

Then, the above random and intermittent vibrations stopped, and I started getting a faint 'whirring' or 'grinding' sound coming from the nearside front wheel.
To cut a long story short, the bad state of British roads (potholes, sunken manhole covers and gullies) took their toll on my Nearside bearing.

Initially I ordered a Febi bearing and hub replacement, thinking it was a quickish job to replace this, but had an absolute nightmare getting the brake caliper holder off to get to the rear bolts to change the bearing and hub out. 6 cobolt drill bits later and a lot of brute force I got absolutely nowhere.

I've ended up removing and replacing the whole Steering knuckle, bearing & hub, both top suspension guides (seized pincher bolt so couldn't get these off the knuckle part), lower front and rear wishbones (again - seized pincher bolt so there was no getting those off either) and various bolts and nuts (mostly all seized or properly welded should i say).

I'm taking mine out for a test drive tomorrow when I finish putting everything back together again, but I am confident this has solved my issue now. The Bushes on the arms were all pretty trashed (split) so the ride quality wasn't that great before, and the job needed doing anyway. It's a high motorway mileage car and I am now looking forward to not only having had the bearing replaced, but also new harder suspension on the nearside. Next week I will be changing the same parts on the offside as I have already ordered the parts off ebay which was allowing me to do the job at a fraction of the cost of taking it into a shop etc.

On your problem, the audible rattle is something I wasn't getting. Mine was more like a squeal at times. But i for sure got the wobbly steering wheel whilst driving and also during breaking. You have a similar aged auto to mine and chances are the bearings have reached EOL. But if you do end up having to change the bearing and hub, be prepared for a world of pain, as you will probably find most of the bolts seized.

 

[DarthVAG]

I'm gonna have a little ritual tomorrow and urinate and take a dump on this old knuckle and suspension components. it was a proper a$$ to get it off and in the end was just easier removing the whole thing from the auto side than disconnect everything knuckle side.

 

[pelhamsdetailing]

Had the same issue on my car. First it turned out to be the rear rotors were warped, and a very marginally defective set of front rotors which were intended to cure the wheel wobble under braking all together. The final replacement rotors fixed the braking wheel wobble issue, but it then turned out that the rim itself was effectively an oval. If they've been wheel balanced, then they should have spotted it was any other shape than a circle.

If you are within a year of the front brake rotors being changed, go back and ask them to check. Also, ask them if they cleaned the wheel hub before they put the new rotors on, because if there's any build up, even with all 5 wheel nuts on tight, that will cause a slight wobble.

 

[DarthVAG]

just to report back, new hub and bearing has cleared my issue. no more vibrations and noise.