MOT Advisory - Suspension

Post by **edjones** » Sat Sep 19, 2009 11:22 am

Morning all,

the Minor duly passed its MOT recently, the only slight blot on the copybook being an advisory stating that:

"offside front suspension has slight play in a lower suspension ball joint".

Are we talking a new kingpin here

Thanks in advance.

Post by **Dean** » Sat Sep 19, 2009 6:37 pm

It's definitely the lower thread of the kingpin they are referring to. The only way you will be able to tell the extent of the wear is by taking it apart and taking off the trunnion. It may only need a new trunnion, but worse case, yes new kingpin or a re-thread.

Post by **bmcecosse** » Sat Sep 19, 2009 9:04 pm

Well -since it doesn't have a 'ball joint' - you have to wonder about the place that did the MOT! If it IS the kingpin thread - you may get away with just a new trunnion kit - that should at least take up half of the wear! So 'slight play' should become 'miniscule play'!

Post by **PAULJ** » Sat Sep 19, 2009 9:42 pm

I had the same, He put ball joint because now MOT's are computerised every thing he picks up is from a drop down and theres no drop down for trunnions? Make sure they are well greased. That will get rid of slight play

Post by **bmcecosse** » Sat Sep 19, 2009 9:48 pm

You are just 'kidding ' yourself with grease! It does nothing (to take up play) !

Post by **edjones** » Sat Sep 19, 2009 11:03 pm

Many thanks for all the replies, very helpful. I'll strip it down and see whats what.

Post by **8009STEVE** » Sun Sep 20, 2009 8:52 am

It does nothing

Yes it does. It might give you 12 months extra to do the repair

Post by **bmcecosse** » Sun Sep 20, 2009 10:14 am

Of course it 'lubricates' what may otherwise have been a very dry thread - but it can only take up microns of wear - so effectively does nothing to reduce any play. Thus my comment!

Post by **kennatt** » Wed Sep 23, 2009 8:04 am

with bm here yes it might stop the movement a little but will not stop the suspension from coming apart,Strip it and have a look at the threads,only way to be sure its not ready to pull out of the leg.

Post by **Mick_Anik** » Wed Sep 23, 2009 11:01 pm

I'm surprised one can get a 'pass' if there is any free play whatsoever. Any free movement is a sign that the parts are worn, and with a trunnion the degree of wear increases more and more quickly once it starts to rock due to the hammering it gets in use. Could a slightly rocking trunnion still be safe eleven months later? 8,000 miles later?
Impossible to quantify, so good that you plan to check it out. The top of the kingpin threads should be flat - an inverted 'v' shape is a sign of extensive wear. As stated, a new trunnion may solve the problem short-term......but how long is that?

Post by **bmcecosse** » Wed Sep 23, 2009 11:32 pm

I too am 'surprised' at the pass - but the MOT lad doesn't look ahead - he looks at the car as it is today and makes his judgement on whether it is safe at that time. Obviously this one was concerned about the future - and has wisely issued the advisory. Best to take note and fix it asap!

Post by **MarkyB** » Thu Sep 24, 2009 9:02 am

Good grief, the one person who actually checked the play described it as slight.
10 posts later and it's turning into a death trap!

Post by **edjones** » Thu Sep 24, 2009 11:53 pm

Fear ye not everyone, it will be fixed rather than left. After all an advisory is just that - advising you to fix something!

Post by **bmcecosse** » Fri Sep 25, 2009 10:01 am

Minor kingpin lower trunnions don't take long to go from 'slight ' play to pulling out! It's difficult to detect any play on the car - until it becomes quite 'significant'.

Post by **MarkyB** » Fri Sep 25, 2009 7:18 pm

Really?
How much play do you define as slight?
How long do you define as long?

Pulling out is easy to define, the rest is rather subjective.

Fri Sep 25, 2009 7:35 pm

ed.. and if this teaching you to suck eggs tell me and I will get rid of this comment..

when taking your bottom trunnion off do not forget to take out the fulcrum pin before twisting it off the or you will destroy the upright completely and get some unpleasant comments as well..

as i say i am happy to remove this if it is teaching you to suck eggs.. it is certainly not meant in that terms

Post by **edjones** » Fri Sep 25, 2009 8:18 pm

Thanks for that Charlie. I saw someone else make that mistake a short while ago so know to watch out, leave the comment on for anyone else looking though as its an important point

Post by **bmcecosse** » Sat Sep 26, 2009 9:53 pm

Indeed - but there really isn't any room for 'slight' play - if there is ANY play I suggest, for Safety' something is done about it sooner rather than later!

Post by **edjones** » Fri Oct 23, 2009 2:55 pm

Got the trunnion off today, hopefully my knees will recover soon

The threads look ok to me, though the shorter thread at the top of the leg is a little "V" shaped. The lower thread is nice and sqaure.

Can I ask your opinions please - will a new trunnion suffice or is the thread on the kingpin badly worn?

Thanks in advance.

Post by **bmcecosse** » Fri Oct 23, 2009 3:39 pm

Looks fine to me - I have certainly seen much worse!