Lower Kingpin and MOT

Technical queries or suggestions

Lower Kingpin and MOT

Postby Andrew Faulds » Sat Feb 25, 2012 2:25 pm

My Plus 8 has just failed its MOT at local (not familiar with Morgans) garage due to, quote;
"N/S front (trunion) Ball joint has excessive play (2.2.B.1f)".

It's actually the lower Kingpin bush/rebound spring which does admittedly have slight movement when wheel is pulled and pushed across vertical. The MOT "tick" option box does not stretch to this particular item and this was the closest they could get as far as description goes! Is it worth going back to Garage and ask for a second opinion? I have been told on good authority that slight movement here is not uncommon and it should not necessary be a fail item. Any views or comments would be appreciated, thanks.
Andrew Faulds
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Re: Lower Kingpin and MOT

Postby jack bellinger » Sat Feb 25, 2012 4:06 pm

Slight movment is ok

But there is no actual amount of tolerance in mm. it comes from experience . give it a good greasing before you take it.
if you have a manual take it to the mechanic show him how it works he may be easier on you..

But cos you work your car quite hard it will probably be better just to renew the kingpin and bushes ( movement never gets less only more !!)

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Re: Lower Kingpin and MOT

Postby Barry Sumner » Sat Feb 25, 2012 7:08 pm

If the movement is very slight you lessen it by turning the king pin through 90 degrees (as king pin only wears fore and aft) and as Jack suggests a good grease.
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Re: Lower Kingpin and MOT

Postby Jim Mountain » Sun Feb 26, 2012 11:46 pm


The testing guide says the movement has to be excessive, without seeing it for myself I couldn't tell you if it is excessive or not, but a good rule I use when doing an MOT is, if when testing a component and I think to myself "f**k me, that's bad" then it fails, otherwise I pass and advise it.

The section of the Manual is here http://www.transportoffice.gov.uk/crt/d ... guides.htm

The fail should have been listed under 2.5.3.a so working on the basis that the tester has failed the vehicle on a part that is not fitted to it, if you appealed the decision to VOSA you would win. But if when the car is being retested by a VOSA examiner and the play in the king pin is excessive then they will fail it but for the correct item on the VTS computer.

If you live near me (Chesham) I'm quite happy to have a look at it one night this week for you, or if you want to discuss it over the phone then PM me your number.

Hope this helps.
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Re: Lower Kingpin and MOT

Postby Andrew Faulds » Tue Feb 28, 2012 4:44 pm

Just to let you know - it PASSED on second visit. i gave the king pins a good greasing which must have tightened them up a little bit.
Many thanks for all your advise and help - it's much appreciated!
Andrew Faulds
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