just fitted Mick Miller drive shafts, knocking noise, help!

[Pete Shepherd]

i own a 1970 Elan +2S. my dad recently fitted a pair of Mick Miller drive shafts. since they have been fitted a knocking/thumping noise has started at the rear. it sounds like it is coming from the same area as the drive shafts. it goes in time with engine (gets quicker the faster you go and so forth). i have done between 150miles and 200 and the noise is still there. the car seems to drive fine and i thrashed it around north weald the other day without any problems. my dad is surprised at the angle that the drive shafts go through. should they lay flat? is there something we haven't done that we should have? is this noise normal (i doubt it) ? if anybody has any suggestions i would be very grateful.

cheers
Pete

[nebogipfel]

Pete,

The Mick Miller shafts are excellent and you certainly should NOT be hearing any noise from them.

As a first thing, I would suggest jacking the vehicle so that the weight is on the suspension (the shafts then run at a sensible angle) and rotate the wheels so that you can hear if anything is touching or chaffing.

It is also possible that the stiffer driveshafts have exposed a problem with something else such as the diff mounts or torque rod bushes.

Before you do any more thrashing around I strongly suggest your Dad gets back under the car to investigate the problem.

[types26/36]

No the noise is not normal, something is catching and you need to locate the problem and fix it before any damage is done. Check all of the nuts/bolts are tight and look for signs of something rubbing (check the two bolts supporting the diff are tight) and also the tie rods/rubbers that locate the diff that pass through the alloy diff housing and bolt to the chassis.
There could be a problem with a c.v. joint but if the shafts are new its unlikely, try to establish which side the noise is coming from which will help to identify the problem.
The angle of the shafts should not be excessive with the car on the floor, jacked up they will be at an angle.

[chrishewett]

Pete,
I agree with Brian. You must get under and look properly before taking to the road again. Did you use the lock washers as well as the nyloc nuts? They need to be tightened well with someone stepping on the brake pedal. I fitted mine last week and checked for tightness after 50 miles and one nut was loose. I have retightened and will check again after another 100miles or so.
Chris

[peterako]

Hi Pete,

How are you?

If, after you've checked teh installationm as per other posts,
you still have knocking......

I fitted Mick Miller CV's to my car last year.

They should sit as close to level/in-line (wheel-shaft-diff)
as possible. This will be determined by your rear springs.
Also read the instructions carefully as regards the diff
washers.

They immediately gave a great improvement in handling as
they tightened up the back suspension in the car.

They also highlighted previously hidden shortcomings in the
drivetrain.

1. There is a little (acceptable) slack in the diff.
2. The UJ's need replacing

This latter exibits itself as a knock/clicking at various speeds.
Initially I thought it was the CV's. But definitely the UJ's.

Depending on your soundproofing you'll either hear the
knocking at all speeds or only (as I do) at some.

The noise will only appear while the engine is driving
teh driveshaft.

I hope this helps,
Peter 1973 +2S 130/5 Mick Miller'ed

[Pete Shepherd]

Hi

thanks for everyones help. the problem was found, it was a faulty CV joint. i contacted the supplier and they exchanged it for another. the problem is much better now.

cheers
Pete