Lotus Elan

CV joints - how tight?

PostPost by: steve.thomas » Wed Jan 26, 2011 1:56 pm

Hi everyone,
Thanks for all the useful responses. I've been under the car again and checked everying - couldn"t find anything loose, broken etc. Turning the hub / driveshaft by hand I could not reprduce the noise. I then jacked up the suspension and ran the car in 2nd gear to see if the noise was apparent at higher speed, but again no noise. Wheel back on and test drive - clicking noise again. Realizing the only difference was with the road wheel on, I jacked up again and rotated the wheel by hand - gues what? - a clicking noise. It turned out to be the balance weights just catching both ends of the wishbone where it bolts to the hub carrier. These weights are glued in place but are flexible enough to absorb the shock rather than just be knocked off the rim. Removing a very small amount of material from the weight with a file has solved the problem. What I can't figure out is why this should have happened - I have not swapped wheels around and it's hard to see how the relationship between the wheel, hub, hub carrier and wishbone can change (probably best not to think about it.........).
Steve
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PostPost by: miked » Wed Jan 26, 2011 2:29 pm

What I can't figure out is why this should have happened - I have not swapped wheels around and it's hard to see how the relationship between the wheel, hub, hub carrier and wishbone can change (probably best not to think about it.........).


I don?t know what type of bushes you have but the strut moves forward and backwards under braking and acceleration (within the outer part of the A frame). That?s why Mick Miller sorted out the top hat poly bushes to limit this movement and also because those outer bushes don?t tend to last too long. Sue told me that he would change them at an MOT's 12month after a car had been restored (out of embarrassment). Having had this problem I would say with sloppy bushes you can expect a good 6 - 7mm fore and aft' movement. I had a Plus 2 that made a funny noise when leaving a bend under power. It was the inside of the right wheel grinding on the A frame bolts. Without stress there was adequate clearance. Testing with a lever proved the bushes were shot and an amount of movement.

To be honest this is what blows my mind with high powered Elans still using the old bushes. Perhaps they don?t make them like they used to. I have heard some conflicting report but personally have had some really bad ones.


Mike
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PostPost by: steve.thomas » Wed Jan 26, 2011 3:17 pm

Mike
The A frames and bushes (inner and outer) were replaced about 500 miles ago, so I don't think that is the cause. I can only think that maybe the balance weights have slipped very slightly outwards due to centrifugal force - the glue seems very flexible. Still strange how it only shows up right after doing the CV job.
Steve
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PostPost by: alaric » Wed Jan 26, 2011 11:16 pm

Hi. Have you checked the endfloat of your wheel bearings? I just wondered if the process of tightening the cv joint bolts and messing round with the whole assembly you've disturbed the outer shaft installation slightly, or maybe the rubber doughnuts held it under tension - applied slight torque or tension to the shaft, that's now removed 'cause the CV joints are 'floating' i.e. they're self adjusting for length and frictionless. It seems unlikely that the rubber would make a lot of difference compared to the forces from the weight of the car and cornering but maybe at slow speeds.

Sean.
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PostPost by: AussieJohn » Thu Jan 27, 2011 8:42 am

Sometimes a thin washer is used as a shim between the outer wishbone bushes and the bearing carrier; if you put this on a different side of the bush it will relocate the carrier in relation to the bush which will move the wheel location, could be the problem! It's easy when pulling it apart not to notice this washer, if you found an extra one on the floor later then.........!
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