9 replies to this topic

[SolarB]

A while ago I was driving up a fairly steep unmade track with the family and dog in the car (not particularly pertinent to the problem, but the car was fully loaded). In 1^st gear doing 5mph or so and we went into a shallow pot hole, there was a bang and we lost drive. Phoned a friend for a tow back home and the diagnosis was that the near-side drive shaft (with cage and bearings) had slid out of the inner pot joint, pulled off the boot, thrown out the bearing and then re-inserted itself.

 

A simple fix with a new joint but I am at a loss to explain how this happened. Try as I might there simply isn’t enough play to disengage the driveshaft from the pot joint while the outer end is still bolted to the hub. Engine mounts are new so there is no movement there, suspension is in good condition so again, very little movement.

 

The car is a bit of a mix (A+ engine and box, MK3 sub-frame, 1275GT hubs and discs, unknown drive shafts). Are there different length drive shafts (not side to side but for different models)? I always assumed that they were all the same length but perhaps there are differences and I have a short version.

 

 

[RooBoonix]

Rebound rubbers there?

[SolarB]

Shiny (well, not shiny) new ones. Also bump stops.

[wile e coyote]

Hmm - interesting issue.... there are differences in driveshafts for different applications although I'm reaching a bit into the dim & distant past without success as haven't touched a car other than A+ with pot joints for a fair while so best I can come up with is a quick plagiarise:

 

http://www.somerford...page=page&id=49

 

Clue may be in the couplings used at various stages....that may have necessitated slight variations in shaft length...(I know there are diameter variations) - coupled with bitsa nature of your car...

 

But..theorising a little -  heavily loaded suspension compressed by load and shaft at maximum reach - assuming you did a full lock turn in the opposite direction to the affected joint   . what condition were the inner splines in after this this happened? there is play in the pot joint for obvious reasons so if the "spider" (sorry cant remember the correct term) floated a little it may have gone further into the joint, ripped up / rounded the end of the splines, had a good mangle spitting a ball and re inserted itself when you got out to investigate & straightened up the steering....... ok perhaps a bit far fetched.. And there would have been some fairly nasty swarf in the remains.....

[Magneto]

I don't think you can have a wrong shaft on a pot joint, the different shaft's ends are machined differently for spline length, clips and such.

 

I have heard of this happening to a friend of mine, and he was doing a very similar drive - his P'up is lowered, and he has a severely rutted and pot holed mile long drive to his house in the backwoods. 

[Rob Gavin]

this came up on another forum recently, albeit on a low car.  It turned out that the cages were on the wrong way round positioning the balls closer to the opening in the pot joint.  In that case, it failed very quickly, however if yours is a generally standard car, it may be fine until it was loaded up?

[59 Speed]

This happened on mine. Not excessively lowered, but adding a bit of negative camber saw the pots coming out the inner cv.

http://www.theminifo...s-shrunk/page-2

[tiger99]

Negative camber would be a possible cause, as well as lowering. Worn engine mounts can also contribute to the problem.

[SolarB]

Pot joints were about the only part of the car I hadn’t rebuilt. Until now I didn’t realise that the spider even came off the drive shaft, I thought it was all one piece.

 

The car’s not lowered but probably hit the bump stop when it happened. It’s possible the cage was the wrong way round. Once the balls are removed the cage slides off the spider (?) away from the drive shaft. Is this the correct way around ?

[GraemeC]

The cage isn't symmetrical so can be put on the spider either way round.