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MG MGB Technical - Is rear end clunk unsafe?

I have been to the archives and was a bit disappointed to see others with the same problem, that is after doing a clunkotomy the problem is back after 1K-2K miles. I now see that other things in the rear end need to be looked into but I don't want to get into it right now. Do I risk more damage or possible failure if I drive it now and again for the next month or so?
Thanks,
Dana
Dana Wilson

I'm sure it is only an audible irritation, definitely not a problem for a month or so, many go on like this for years and I've never heard of the diff breaking up.
Paul Hunt

It may have something to do with the quality of the replacement parts that were used. I've heard of quite a few people complaning of short lived repairs. RAY
rjm RAY

I hate thinking I went to all that trouble to install crappy parts. Other than the clunk, my B is running well. I wish I could cure it once and for all.
Dana Wilson

If you have wire wheels, and if the clunk is worn splines, there could be a safety issue as a complete failure will eliminate the brakes on the failed wheel. But, most of the braking is done by the front wheels.

Charley
C R Huff

I'm with CR. I had the "MG clunk" on my WW '63. Had the rearend rebuilt and it went away for about two months of on/off driving. When I replaced the wheels and splines, the noise went away COMPLETELY. IF you have wires, lift the back, set the p-brake, loosen the knock off then attempt to rotate the wheel. It doesn't take much movement to make a good "clunk" or two.
GLP Pelech

Yes, I have wire wheels and have checked the splines in the past. They were fine then but perhaps they should be revisited. Thanks.
Dana Wilson

If it's a Salisbury axle car, be sure the half shaft to hub nuts are tight. Check the driveshaft u joints, preferably by unbolting the shaft, since sometimes you can't feel the slop, but it clunks anyway. And, the drive flange at the gearbox output can be loose, which also causes the clunk (and sometimes a squirrely speedo). All these tend to show up after you've fixed the worst of it by replacing the washers in the diff.

FRM
FR Millmore

Wheels *have* to be loose on the splines to some extent, or you would need a press to get them on and off. What happens is that in accelerating and braking they all slip back and fore and impact on the faces of the splines. Originally they aren't audible, as the splines are hammered and get thinner they become audible, then the tops of the splines get sharp instead of flat-topped, then they lean over, finally they shear off. On rears you are more likely to get stripping on acceleration than braking as the braking force is much less than the acceleration force. Fronts are only likely to shear under braking, but then unless you do a lot of reversing and braking there is a lot less back and fore movement of the wheel on the hub. If you slacken the hub and lock the drive-shaft you will *always* find free play, this is not a good test of wear.

On my last MOT (annual test) the tester reported a hub nut was loose, which seemed unlikely to me. Unless he could lock the half-shaft or drive shaft how would he know? Even then he would have to have the spinner off an look at the relative movement between hub and half-shaft, and they don't undo the spinners in the test. With the hand-brake on I did find a slight back and fore movement of the wheel but this was the shoes moving on the backplate, nothing to do with the hub on the half-shaft or the wheel on the splines. These young kids know nowt about classic cars, the usual chap probably wouldn't have mentioned it, let alone documented it.
Paul Hunt

This thread was discussed between 10/11/2009 and 13/11/2009

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