pow
Premium Member
Registered: 11th Sep 06
Location: Hazlemere, Buckinghamshire
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Dad's new motor (ofcourse it would be the one he's own for all of 5 minutes wouldn't it!) has developed an interesting problem.
It drives in a straight line perfectly fine and drives at over 5 mph perfectly fine, turns without any problem in the steering. There is a little bit of 'play' like it has shot track rod ends which you might expect on a 12 year old car.
However, when you reverse it off the drive or manuover forwards and apply any lock at <10mph, the steering wheel (and front wheels) skip and you get a sort of thudding noise as if they are on ice or you have a flat tyre? He's dropped it into a mechanic while he's away for a couple of days and they've said it's the diff that's the problem, nothing on the suspension or steering. I find that a little odd, as if the diff was shot surely it'd be making all sorts of noises while driving forward and turning not just more than half a turn at <10mph?
Car is a mk1 Merc A Class, 1.7 diesel auto. Any advise?
Thanks!
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Mike
Organiser: North West and North Wales
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Registered: 20th May 06
Location: nr. Skipton, North Yorkshire
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I was thinking it sounded diff like as I was reading it. Have you ever watched some of the Essex lot parking up at Trax with their welded diffs? They sound terrible when they're manoeuvring. Have you tried standing and watching the wheels whilst someone manoeuvres it to see if they're spinning as they should?
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Ian
Site Administrator
Registered: 28th Aug 99
Location: Liverpool
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I'd be watching the wheel speed live data before taking anything apart
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--ToM--
Member
Registered: 23rd Nov 07
Location: Wirral
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Diff
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pow
Premium Member
Registered: 11th Sep 06
Location: Hazlemere, Buckinghamshire
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Umm it seems like it is the diff then. Been talking to an exs brother today who's a merc spanner man and he's happy to drop and refit the box in exchange for some it support. Winner.
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Ian
Site Administrator
Registered: 28th Aug 99
Location: Liverpool
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How does it feel to spin the wheels with both fronts in the air?
Not sure there's much to fail in an open diff that wouldn't either give you no drive at all or a complete lock across all drive. You'd do well do damage in such a way that it maintained drive in a locked position but didn't loosen off when you turned at normal speed.
If you'd welded it - perhaps.
If you were talking viscous centre diff type of thing because they seize - same type of thing.
If it was an open diff and now chooses when to seize - I'm not convinced. I'm also not convinced it wouldn't un-sieze and shit bits out the side the first time you went round another corner.
Pics of it in bits anyway, be interested to see the failure mode as that will be a new one for me.
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pow
Premium Member
Registered: 11th Sep 06
Location: Hazlemere, Buckinghamshire
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I understand your thinking there Ian, I'll speak to the garage later and ask about it 
Thanks for moving
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--ToM--
Member
Registered: 23rd Nov 07
Location: Wirral
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diff.
Seen it loads of times on various cars especially on the classics. More so on cars with LSD. Really noticeable at low speed but absoloutley fine once your were going, but dog rough when manoeuvring. As said felt like the diff was welded.
Worn shims, and planet gears etc on the old ones used to be really common, strip down re shim reset all the pre loads etc used to sort them out.
Not sure how serviceable they are on the newer stuff like.
Ian's brain must have melted by now all that over thinking that happened in that post above, fuck me my head hurts just reading it.
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pow
Premium Member
Registered: 11th Sep 06
Location: Hazlemere, Buckinghamshire
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90% sure it is. Going to drop the box off and have it looked at. He has some sort of emotional attachment to this car
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Ian
Site Administrator
Registered: 28th Aug 99
Location: Liverpool
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Sorry my experience is boy racers and Land Rovers and they typically explode all over the floor when they're ready to fail.
You'd presumably see planet wear as play rotation on one wheel while you held the other one? I had that on one of the Discos and winding up the preload sorted it. Was just knocky though, didn't get as bad a skipping.
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pow
Premium Member
Registered: 11th Sep 06
Location: Hazlemere, Buckinghamshire
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I suppose a test would be to do it with the fronts off the ground?
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