A 'shocker' at MoT time with Vauxhall Combo C van...

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Buckinghamshire, Darn Sarf
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My 2010 van failed the MoT this year, some minor things like a cracked driver's side mirror, headlamp aim too low, then the big one...three tyres with tread too low; two front and one rear.

Now the rear ones I can understand. A couple of years ago they were on the front when the lower track control arms needed replacing, consequently they wore excessively on the inside edges. The solution; move the unevenly worn ones to the rear, correct the tracking, and fit two new tyres onto the front.
So the track control arms were replaced, the tracking adjusted, and the new tyres fitted. It's a beam axle at the back, so there should be relatively little wear to the tyre inside edges, more to the outside ones - and so it proved.

In the intervening two years two front dampers have been replaced, along with both steering track rod ends, and the tracking re-set.

This year the shock was the failure on the two front tyres, both hardly worn on the main tread (about 5mm left on each), but both so badly worn on the inside edges that the cords were exposed, indicating major toe-out on the tracking. I can only assume that the garage measured and set the tracking wrongly, though I can see I'll get nowhere with that argument and, let's face it, the state of the roads and number of potholes gives each and every tyre dealer a free pass!

I'm now investigating what mechanical item could have worn, bent, or failed to the extent that it
a) confused an inexperienced tracking setter to adjust the tracking so badly
b) deteriorated in the one year after the track rod ends that the tracking was cocked.
Supplementary information:
1. I never drive up or on the kerb, except when reversing across it into my driveway. Kerbs are part of the pavement, and pavements are solely for pedestrians.
2. I never turn the steering wheel unless the road wheels are rotating.
3. The anti-roll bar mounts creak, they always have, and applications of silicone lubricant quiten them only temporarily.

On inspection today there is a gap of about 2mm between the top of the inner wing and the base of the rubber-faced locating washer (that's the large 'washer' seen under the nut when looking under the bonnet). When the van is jacked-up this gap disappears as the strut extends.

My questions are:
1. Is this gap, and it's behaviour, normal?
2. Could a slightly out of true (steel) wheel rim confuse the tracking machine/operator?
3. Apart from the compliance of the rubber mountings (which seems normal) are there any other common wear items that could cause this rapid wear to the inner bead?

MM
 
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I’ve been in the trade years and I rarely see wheel alignment carried out correctly. I always train our students to (a) First, jack up the car and check all steering and suspension joints and wheel bearings for play - any play or wear must be corrected first otherwise you are wasting your time. (B) car must be on level ground - you'd be surprised at how many do it on a slope. (C) tyres must be checked for correct size and aspect ratio and pressures must be correct - never seen that done anywhere. (D) Suspension must be settled - bounce the car and roll it backwards and forwards. There are other things too but they really are minor considerations. The biggest problem though is setting up the equipment to the vehicle correctly and understanding the settings. Experienced mechanics and tyre fitters still fail to understand this and constantly get it wrong. Nowdays I just have basic laser equipment to check alignment and people still struggle to use that equipment correctly. There are much more complicated 4 wheel setups than I have. Usually those specialist places have top notch equipment and are fully trained in their use. Mind you, they are not charging £13.95 plus vat or whatever tyre places charge these days for a semi-skilled tyre fitter to have a go at doing it!
 
Always good to hear from you, MM - something different every time!
Anyway.....
1) With the wheels dangling in air, there is no load on the front strut so things do tend to rattle around a bit....however, its always a good idea to replace the strut top bearing when the springs are done - some vehicles are more prone to issues here than others. All you can do is to ensure the top strut is tight (It will be.)
2) It takes some expertise to set up tracking gear and I suspect that the person that did yours had little idea.....if I take my car in for tracking I slacken off the track rod end nuts to make the job easier. The gear that Kwik Fit have is awesome and I reckon it's as good as it gets - so long as the operator knows what's what. Happily my local branch let me have a go from time to time.
3) Well worn wishbone bushes will knock out tyres brilliantly but the car will show negative camber. Shoite tyres will also wear in funny ways!
John :)
 
With the wheels dangling in air, there is no load on the front strut so things do tend to rattle around a bit....
That’s true. When a car is logged on for the MOT test, sometimes special notes are flagged up. Many cars now have special notices mentioning that there can be considerable play or lift on the struts when there is no load on them and that is a 'design feature' and should not be failed on that play.
 
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Always good to hear from you, MM - something different every time!
Yes, I do seem to be hogging the airways at present, but what would you expect when the advice is so good, and the folk too?...That and I'm half way through two weeks of house arrest following a foreign trip! Even my Faceache 'friends' are hearing from me.:mrgreen:
Perhaps if you break your heating I can be of some reciprocal service to you?

MM
 
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