Alleged front shock MOT fail

Post Mon Nov 24, 2014 11:06 am

Just been failed the MOT and told that the front o/s shock is knackered.

I drove home from the MOT centre over a series of cushion style road humps - driving either n/s or o/s side wheels over the bump. There is no appreciable difference in spring resistance or damping effect for either side.

Bouncing the front corners there is no sign of any failure of damping. The ride height left to right is identical.

Very recently when I changed the o/s top-mount, the shock seemed to me to offer proper resistance and no leaks or play evident.

BUT - he did show me how by using a pry-bar under the raised wheels, the n/s does not move whilst the o/s side compresses the spring fairly easily. Putting to one side the fact that the pry bar surely tests the spring and not the shock, what is going on?

And given that the car is a Tech 1 Sport, with Boge 51mm shocks, can anyone suggest where I can get replacements without getting a mortgage.

Cheers.

Post Mon Nov 24, 2014 11:46 am

you could do with having a word with maxfield on here, he's an mot tester.

as for replacement inserts, try gsf, euro car parts, carparts4less, local motor factors,

Post Mon Nov 24, 2014 11:49 am

steve_k wrote: as for replacement inserts, try gsf, euro car parts, carparts4less, local motor factors,

Thanks - but the problem with the usual suppliers is that when you tell them that the car has M-Tech sports suspension they just look at you blankly.

Their reference books tend to only deal with a standard 325i.

Post Mon Nov 24, 2014 11:57 am

http://www.buypartsby.co.uk/details/BMW ... -absorber/

try this place ^^^^^^^^^^^^^^^^^^^^^^^^^^^

local to me but as far as i know they do mail order aswell.

also being KYB you know what you are getting.

Post Mon Nov 24, 2014 12:36 pm

The pry bar test is for testing lift in ball joints and top mount play.

What's he actually failed it on?

Post Mon Nov 24, 2014 12:43 pm

maxfield wrote:The pry bar test is for testing lift in ball joints and top mount play.

What's he actually failed it on?

Yes - I have now had a look at the MOT Testers Manual and I am pretty annoyed. He has failed it on the shock absorber not working. seems to me that the only way to test that is pressing (or pulling) down on each corner and failing if the shock shows negligible damping effect.

I guess, with the benefit of knowing of the alleged problem, when I bounce the o/s front, it bounces back fractionally quicker than the n/s but there is NO appreciable secondary bounce and I really do not think that the shock could be said to have 'neligible damping effect'.

Going to go back and see if they cannot be persuaded to re-consider.

Post Mon Nov 24, 2014 12:47 pm

Bounce test is not part of the MOT test. To me it sound like the spring/shock is a bit weaker than the other side, maybe one side is newer than the other. Aslong as its bolted up correctly and it's not excessively leaking there is no reason to fail it.

Go back and tell them to look at the manual correctly, failing that threaten them with VOSA.

Post Mon Nov 24, 2014 12:50 pm

maxfield wrote:Bounce test is not part of the MOT test.

Thanks.

Is this wrong at 'method of inspection 5.'?

http://www.motuk.co.uk/manual_270.htm

Post Mon Nov 24, 2014 12:53 pm

Yea, not part of the test any more.

Here's the actual testers manual.

http://www.motinfo.gov.uk/htdocs/m4s02000701.htm

Post Mon Nov 24, 2014 1:00 pm

maxfield wrote:Yea, not part of the test any more.

Here's the actual testers manual.

http://www.motinfo.gov.uk/htdocs/m4s02000701.htm

Very helpful - I am much obliged to you.

Post Mon Nov 24, 2014 1:59 pm

As Maxfield says, there's no actual test for a shock absorber to actually do anything these days. As long as it's not leaking oil, it can be an empty tube with nothing inside, and not fail.
It sounds like your shock absorber might be partly seized, and should have resulted in an advisory, not a fail.

Post Mon Nov 24, 2014 2:21 pm

Their mistake - fail was actually a pass!

Zone 1 - Dodgy MOT garage 0.

Many thanks to all particularly Maxfield.

Given that I don't think that they were under any illusion that anyone but me was going to do any work on the car, and that they were fully aware that the 'bounce test' is no more, I am not sure what they were on.

Brian, clearly there is some appreciable difference between the sides, but whatever it is it does not show up on the road. Now I don't have the pressure of the MOT hanging over me, I'll have to pull it apart and see what is going on.