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MG MGB Technical - What is that sound when I go over a bump?

Hi All,

Whenever i hit a pothole, or even go over a speedbum at the normal speed, I get this horrible 'thump' sound from the left front wheel area?

There is no noticeable damage from a visual inspection. I'm new to MG's, so maybe someone here knows if this is a common problem, ie. simply worn bushes?

Any help on diagnosing the problem would be much appreciated.

Thanks,
Rudi.
Rudi

Support that corner of the car safely, with the other wheel on the ground, and try and rock the wheel side to side and top to bottom. There *should* be some play which is the end-float or free play in the bearings, so you need two of you and the other one looking for any additional play in the kingpins top or bottom, upper and lower trunnions, damper arms and mountings, A-Arms inner and outer, track-rod end, and if it is the passenger side it could also be the bush at that end of the rack allowing it to move up and down or fore and aft relative to the rack tube. Could also be excessive play in the bearing, and loose wheel nuts of course. That's before you get to looking for the exhaust hitting the bodywork, broken engine mounts, and so on.
Paul Hunt 2

Rudi,

Check the rubber pads between the front main cross member and the frame of the car.

Also, for what it is worth, I was getting a thump on my car and it turns out the shock was low on oil - easy fix.

Robert
Robert Browning

Make sure to place the jack under the lower control (A) arm. Otherwise the spring pressure will keep everything under tension and you won't see any movement.
John H

A thump when going over speed bumps is usually worn swivel hubs impacting against the flange of the kingpin.
Steve S.

Pedistrian?


Dan Robinson

Rudi

You might also want to check the bottom wishbone bolt at the king pin. I believe that Moss USA sells what it calls the lower trunnion kit. If the bolt seizes in the lower king pin then the suspension will clunk as you go over a bump. This is fairly common and usually results from lack of lubrication in this area.

If this car is new to you it might not be a bad idea to check out the king pins etc for movement, lubrication and seized bolts.

Just my 2 bits

Brian
Brian Smith

This thread was discussed between 03/10/2007 and 05/10/2007

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