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MG MGA - Rear spring bolt support

On replacing the bushes in my rear springs I notice that the front bolt fixing rocks slightly in the holes in the flanges on the chassis. The slack goes away when tightened up due to the rubber bush getting compressed. This is similar to the problem with the front suspension when the holes in the wishbone arm become worn. Is this a common problem and what kind of tolerance is acceptable? If it needs to be remedied is there a solution that avoids welding -such as over drilling the holes and using a washer with a small sleeve the thickness of the metal?
J H Cole

"The slack goes away when tightened up due to the rubber bush getting compressed." - The only contact with the mounting bracket should be through the centre metal tube of the bush, not with the rubber. If the holes in the bracket are worn large enough for the metal inner tube to protrude, they must be repaired. Easiest way is to spot some MIG weld on the edges and file it down to correct ID and file it flat both sides again. Clamp a piece of copper sheet to close the hole area and do the weld to avoid burning through.
Then if there is still play sideways you can use an accurately sized washer to take it up. But it must clamp correctly to the inside tube.
Also, the new bush must be properly centred in the spring eye.
The solution you propose is not good - it will allow rotation and wear of the mounting hole.
Art Pearse

Art, not quite sure of how things are working here. My new bushes (Brown & Gammons) have the inner sleeve of the bush projecting just forward of the rubber surround, the outer metal sleeve is further back and does not make contact with the sides of the bracket. When the bolt is tightened up I think the inner tube becomes clamped to the sides of the bracket and I don't think the rubber touches sides -at least not with the bush supplied to me. The only way its possible to stop the bushes rocking is by torquing up the bolt so that's there's a lot of friction with the bracket but I'm not sure this makes good engineering sense. The inner sleeve is quite thick so at least at present there's no risk of it being forced through the hole but in a perfect world I think that the bolt should be a tight fit in the bracket hole. I'm surprised this is not a more common problem.


J H Cole

The bush looks good, and it is supposed to be clamped tight to the bracket so the inner tube cannot rotate under load. The rubber provides the rotation. Sounds like you just have a little bit of slack in the bracket holes, but not enough to let the inner tube stick through. .
You could weld a washer to the outsides of the bracket, with a proper fit to the bolt
Don't forget to grease the bolt against rust.
Art Pearse

This thread was discussed between 25/11/2009 and 26/11/2009

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