Could a CV replacement cause bearing failure??

[aerotec]

Hi all,

I have just picked up an 09 A4 Avant 2.0tdi 143. It had a failed CV joint on the drivers side with the usual clicking on turning but also fairly bad vibration at mid-70mph.

A few weeks back I swapped out the CV joint. I didn't dismantle any of the suspension assembly, I just removed the full axle and swapped out the CV joint. Refitted with 200nm and 180 degree turn. Took it for a drive and it was running nicely with vibration much lower but never as smooth as by B5 A4 I had before.

I have only done some short trips past couple weeks but this weekend I had friends in town and we did a few trips out of town. I could sense something wasn't right as there was a rumble when I was reversing with a slight turn, vibration at 50mph+ and when turning it would increase the turn radius without me turning the wheel further. I took the car off the road and we reverted to Uber!

I have just jacked the car and the front wheel easily has 2cm play! It was very loose! Wheel is secured to the hub correctly, hub bolt is still tight but as I wobble the wheel I can see the CV joint move inline with the wheel so the CV joint still appears to be secured to the hub. So...all I ca think is that the bearing has failed badly. There was never any rumbling from the wheel and turning the wheel does still kind of feel smooth.

I need to strip the assembly down to take a look but can anyone else off suggestions as to what could have gone so catastrophically wrong as a result of the CV joint replacement?

Thanks all, Richard

[FrenchAudi]

Did you lower the car onto its wheels during driveshaft removal? If so you may have damaged the bearing.

There is a warning in my Haynes Manual (probably also in the Bentley manual) in the section on removing driveshafts, which may also apply to your car:-

Do not allow the vehicle to rest on its wheels with one or more of its driveshafts removed, as damage to the wheel bearing(s) may result. If moving the vehicle is unavoidable, temporarily insert the outer end of the driveshaft(s) in the hub(s) and tighten the driveshaft bolt(s). Support the inner end(s) of the driveshafts to prevent damage.

[aerotec]

Hi FrenchAudi,

Thanks for the reply. No I had seen that also but hadn't needed to move the vehicle. I did jack the hub up at the lower arm ball joint so as to help me get the shaft out and back in again.

After re-fitting the drive shaft I tightened up the hub bolt as much as I could before re-fitting the wheel, dropping it to the ground and then torqueing to 200nm + half turn. At that point on a test drive there was a slight noise on reversing and turning but I thought the CV joint maybe needed to spread the grease fully and bed in a bit. A high speed test drive showed the 70+ vibration greatly reduced.

When I drove this weekend it was noticeably worse with vibration over 50mph. That's when I decided to drive home gently and park up.

I am wondering if there is anyway the hub bolt is tightened but the CV joint isn't seated ok and it has allowed the bearing to open up? But when I lift the car and roll the wheel it does still feel smooth with no rough bearing noise. I need to get the disc off and take a good look this weekend but wanting to prep for any parts I might require.

I can pick up a LUK bearing and a Febi hub for £135. Anyone know if a home mechanic can fit the hub to the bearing without a press or would I need to find a friendly garage who would fit the parts for a few £££s?

[Rob69]

I can only think when you tightened the hub bolt the driveshaft splines have picked up in the hub and the driveshaft has not come fully home to support the bearing. can you look round the back and compare the depth of insertion to the other side? I've never done a front bearing on one of these but have heard of trouble getting the bearing out of the aluminium hub carrier ( I think some are / were aluminium?)

[aerotec]

Hi Rob,

When I fitted the new CV joint i did a test fitting and it appeared to slide home ok. With a nice solid donk as it hit what I think would be the bearing inner face?

Now when I rock the wheel I can see the CV joint move the same amount and it appears to be as much inserted as it was before. I will remove both front wheels and compare them. All very strange!

[FrenchAudi]

Maybe someone gubbered the bearing before you got the car, or the housing in the bearing carrier is worn.

[aerotec]

Yeah it could be that. It came with a new MOT but the cv boot was pulled right of the joint and it was badly clicking on turns so clearly some scam MOT! I am now thinking this worn bearing/housing is the cause of the wheel vibration I have had. Just strange it has never been this bad until after I carried out the CV Joint replacement and even then a test drive after the cv joint was changed didn't show this issue as bad as it was this weekend.

I'll post back here with what I find. I am probably going to get a garage to do the repair if it needs a new bearing unless anyone can tell me how easily I can fit a new hub to a new bearing?

Just had a quote in of £218 for a new bearing with a SNR bearing.

[FrenchAudi]

You'd better read up on how to replace the bearing before you try yourself, assuming the housing in the hub is OK. A press, mandrels, support plates, and a couple of special tools are needed for mine.

It's just possible someone made a shoddy repair on the housing, e.g. bearing seal or similar, and it was disturbed when you fitted the new joint.

[aerotec]

If I did it myself I would get a new hub as well as bearing assembly but I see it can sometimes be difficult to pull the hub and bearing housing from the suspension upright. If the garage will fit an OEM bearing for around the £200 range I will just book it in with them. I managed rear bearing replacements on my B5 A4 but that was fairly easy to just fit the new bearings in to the new rear discs.

[Crasher]

Extracting the bearing unit from the upright can be an appalling task, a steel bearing holder in an aluminium hub for ten years, you can imagine.... The one below needed a full new upright as it would not come out even in a ten tonne press