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MG MGB Technical - King Pin Wear

How much wear in the king pin assembly is acceptable before replacement of the pins and bushings are recomended?
Thanks,
Scott
Scott Shirk

A few mm of lift is not an MoT fail here. Usually I do them when I cant get the wheels to balance and king pin wear is the last resort. The amount of wear is subjective in an MoT here, but I think they fail the driving pleasure test before the safety one.
Stan Best

Any perceptible movement!

It is a good idea to completely strip and clean the whole swivel pin assy and check for play & wear with no grease.
Chris at Octarine Services

I have them completely apart. It looks like when they are new there is 1.5 to 2 thousands clearance in the bushing. I have about 4 thousands with a new pin. Assembled and using a dial indicator I have about 1.5 thousands movement. Trying to decide if it is worth replacing the bushings for that amount of wear considering the cost of the reamer.
Scott Shirk

Leave the bushes as they are - any less play than that and the grease can't get round to do its job.
Chris at Octarine Services

Absolutely, unless there is some play or end-float between the pin and the swivel hub you won't get the grease through the top joint, but the maximum is 2 thou. It's also why the front suspension should be greased with the weight off the wheels, which 'opens up' those bearing surfaces. Just been though this on my V8, investigating a clonk I seemed to have 3 or 4 mm of play when assembled. Bought a set of shims and thrust washers, but despite the shims being three different sizing numbers five out of six were the same thickness! Eventually when I got the correct shims I found that even going up one thickness removed all the play on one side and I couldn't get any grease through, so I reverted to the originals. Also the new thrust washers were *thinner* than the old, at 0.179" as opposed to 0.184", so I left those in as well. All rather a waste of time.
PaulH Solihull

This thread was discussed between 14/11/2010 and 15/11/2010

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