Soft thumping

[StressCraxx]

All great advice from the gents who replied after me. I'm concerned you may have a loose bearing fit to the housing. The housing should be warmed to remove the bearings if you are able.

[david.g.chapman]

Thanks for those enthusiastic replies!

I mentioned that the old shaft had showed signs of spinning. The spinning had worn the shaft under the outer bearing, resulting in the play. The bearings themselves have only a trace of play. My bearing carrier still fits new bearings quite well, as I do make use of my blowlamp/oven and freezer where required!

My parts from TTR have arrived - next day delivery! I will reassemble over the next few days, looking carefully for the cause of the thumping. Removing the shaft may have cleared any obstruction, but I will see.....

Cheers,
Dave Chapman.

[StressCraxx]

David, the stub shaft spinning and wobbling in the bearing could very well be the cause. Doing the other checks are simply a process of eliminating other possibilities. Best wishes to get it sorted so you can get out for some fun!

[alan.barker]

The stub shaft worn by bearing happens often. When it happen on a 1970 +2S i owned i got it "metal sprayed" .
Alan

[StressCraxx]

Metal spraying is an excellent solution. We frequently used the process to repair machinery shafts. Finish grinding will give you more precise finish dimensions than turning in a lathe.

[david.g.chapman]

It's all back together now, and there is no thumping from the bearings or the rest of the axle assembly.

As to what caused it, I am still not sure - just that the stub axle would have been tilted (as mentioned) and something was just beginning to catch. I can't see any witness marks to point the way.

The old bearings are hardly worn and turn freely.

A couple of things to note during re-assembly:

1. The TTR stub axle re-located the rear brake disc inwards by a fraction of a mm. I could have shimmed the caliper to compensate, but ended up easing the inboard pad a fraction to stop it binding. Works fine now.

2. The holes in the TTR stub axle are smaller than the old axle and a close fit to the drive shaft threaded pins. This meant that I was unable to fit the shaft inboard end first. I manages to fit the drive outboard end first as the diff output shaft is original, has larger holes, and allows the drive shaft pins to come in at a larger angle.

Happy motoring,

Dave Chapman.