Urgent advice needed: propshaft

[A18RPF]

I'm supposed to be taking my e30 round the NÃarburgring this weekend. Due to unforeseen and tragic circumstances the car is still in the workshop. It went in with no problems (except the fact that the fuel pump died on the way but this has been replaced and the car runs again) and I thought it a good idea the have the clutch changed. The mecahcanic also took the prop off the diff end to try and swap the fuel tank, but he couldn't get the rusted bolts off without snapping them. However, when the car came off the ramps after the cluttch change it has developed a nasty vibration from the prop, turning into a severe banging even at slow speeds. They've fitted a new centre bearing but the vibration is still there. He assures me that the prop was marked before disassembly and went back in the same way. So what has knocked it so far out of balance
Any advice would be greatly appreciated, as my time is running out fast

[gooner1]

Did your mechanic pre load the propshaft when refitting?

[Ianb]

Did your mechanic pre load the propshaft when refitting?

Can you explain, do you mean push the bearing fwd prior to tightening the slide bolts ?

[gooner1]

Correct Ian, quote nicked from a previous thread.

...prop centre bearing needs pre-loading ...............from its non pre-loaded position,slide the bearing forward(you will see that there are slots to adjust this, where the two secureing bolts clamp the bearing to the body) approx. 4mm to 6mm ,re-torque the secureing bolts and then its pre-loaded.

[Rtaylor2208]

When he changed the bearing did he change the carrier as well?

Last time I bought a new bearing it did not come with the carrier and I had to buy that separately.

The carrier can rip causing the whole of the prop to bang about, especially noticeable under hard acceleration.

Also I was under the impression that the prop can only fit together in two ways, so if its out this now split it, rotate then re-join.

[DanThe]

Which bolts were snapped? If it was the diff end then they are special studs that press into the prop
Either way I suggest you get the car to somebody that knows what they are doing!

[A18RPF]

That would be the best option but time is a factor. It's obviously something they've done wrong putting it back together, so they're trying again from the start. They did pre-load the bearing the first time though. Stressed ain't the word!

[DanThe]

Getting the car in a condition to drive to Germany and back is the most important factor, can you trust the garage to do this? Its not like your just driving round the corner, no point limping it there and back

[A18RPF]

The garage has said they've done all they can, but the vibration is very much there. It's dependent on road speed and feels like it's coming from the back end

[jonny323i]

My car is very similar after having the prop bearing changed but it was banging badly before being changed so I will be watching this for the outcome

[DanThe]

If the vibration wasnt there before then the garage has either fitted poor quality parts or they havnt done the job properly, or worst way they have damaged something

[A18RPF]

That seems to be the case, they can't work out where they went wrong. Hopefully a specialist will be able to help tomorrow. Prayer is my only other option

[bdx]

Re-check alignment marks on prop, usually a white dot/mark on each section.

All flanges correctly mated and bolts tight.

Carrier bearing not trashed by poor assembly technique.

[A18RPF]

Well the trip to the ring had to be postponed of course, the car couldn't move faster than walking pace. I stuck it in the garage and forgot about it for a week or so. Just been to try and work out the issue and the silly c***s had bolted the prop directly to the gearbox output flange rather than to the guibo, leaving the guibo flopping around uselessly. Fitted it right and the car is as it was. Safe to say I'll be taking my cars elsewhere in future!

[Motorhole]

[Speedtouch]

That really is lame for a so-called professional garage!

[Idol]

Name and shame!