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Heavy clunk from rear


z7

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I've noticed the appearance of what I can best describe as a heavy clunk from the rear, L/H.

 

It feels like something that should be sprung or have a rubber endstop isn't or doesn't.

 

My initial thoughts were shock absorbers but having deliberatly driven over pot-holes and drain covers (for a change) I now no longer think this to be the problem. Besides, I think, they're only a year/4-5k miles old, as is the car.

 

I can seem to reproduce it when re-engaging gear. Which may suggest the LSD(?)

 

Might it be the A-frame bush(es)?

 

Not really knowing how things hang together in the axle/suspension area, I don't know what to check or how.

 

Does anyone have any thoughts on possible causes and how I can test for them?

 

I have searched the archives but have been having problems with my connection.

 

Thanks

Adil

 

 

Edited by - adil on 8 Jun 2002 22:53:14

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a few thoughts / suggestions in no particular order...

 

1) has the big sticky out lump of diff been cut off? - if not it will hit the middle of the dedion tube as it moves up.

 

2) if its a live axle the a frame bush is a likely candidate - I have a dedion so don't know how to tell if itys gone from looking at it.

 

3) take the wheels off and try all the nuts/bolts with a spanner - are any loose?

 

 

 

Dave Hooper - North London

dmch2@lineone.net

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a few thoughts / suggestions in no particular order...

 

1) has the big sticky out lump of diff been cut off? - if not it will hit the middle of the dedion tube as it moves up.

 

2) if its a live axle the a frame bush is a likely candidate - I have a dedion so don't know how to tell if itys gone from looking at it.

 

3) take the wheels off and try all the nuts/bolts with a spanner - are any loose?

 

 

 

Dave Hooper - North London

dmch2@lineone.net

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I had a klunking sound (and a sort of jolting effect) coming from the rear of my live axle 7 when I put my foot down/changed gear. Phil Waters replaced my a-frame bushes (and the rest of them - cheers Phil!) and the problem disappeared.

 

My bushes were 6 years old and had covered 9k miles eek.gif - when they came out, there was virtually nothing left of them!

 

A-frame bushes were really cheap from Caterham, so it's worth changing them. Aren't they supposed to be changed every 3k miles?

 

Den

 

 

teeth.gif - Self portrait - still unable to remove the smile!

 

 

Edited by - Dirty Den on 9 Jun 2002 12:23:33

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Adil - just caught up with your e-mail re this. Thought your e-mail was at work only (but not so sure now) and have no phone no. for you.

 

A-frame bushes are the cheapest/easiest thing to check first - you're live-axled aren't you? Then whip off the wheels and have a look at everything. But even with car on axle stands it is hard to move the suspension through its full range of movement with a jack, and even if you did it would be at 'low speed' so may not audibly reproduce any suspension related clunk.

 

I'm really busy just now - although I have to head out your direction later on. Could have a quick peek with you.

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Like Kenny, my brand new SLR - 440miles old now - does this.

 

I've checked all the rear suspension but there is nothing obvious to cause it, except some slight play in the diff. I definatly cut enough off the casing to avoid the de dion catching.

 

So far I've assumed it was due to poor conection between brain, foot and left hand, and that in time it might get better.

 

Anyone else with an SLR care to comment?

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OAP, I too have been under car for a check, all seems OK. With car in gear in garage if I push it I can replicate the clonk, so I guess it's diff backlash. Thing that throws me is that when I personally fitted AP suretrack to my old VX it never did this. Also whilst on the subject when car is ticking over the normal gearbox rattle which I also had on quaffe in VX stops when clutch is depressed.....but it's humungously loud, louder than in my VX and louder than in Mavs SV with the same 6 speeder......is this because of the SLRS AP clutch I wonder? Also box sounds like a straight cut when I lift off, particularly in second. Cars done 350 miles.

 

Kenny SLR

 

PS 2 drips from diff and one from g/box per night....I will be mentioning these points at first service.

 

 

 

 

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i have/had a rattle from the 6 speed that can be removed by pressing the clutch as well. The box is at Road and Race now (i send it for a service whilst it was out the car) so I'll let you know if they find anything nasty in it.

 

Adil - I'm not sure how load you mean by heavy. Diff backlash and shunt in the drivetrain is very loud if you're used to an S Class or a Lexus, and merely loud if you're used to a cavalier etc.

 

See if you can get it rolling the car back and forth as someone suggested.

 

Dave Hooper - North London

dmch2@lineone.net

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May be a long shot, however worth checking

 

my 97 Superlight had a similar noise, especially though the right hander at Craner

 

when Sebah examined the car they found that the rivets under the drivers side had failed.

this they have seen on similar aged cars, they have reported to Arch and Caterham

 

don't all Caterhams make a host of strange noises

best bet drive at 7500rpm all the time!!

 

 

 

the not so light Superlight

 

Edited by - K16 TOY on 9 Jun 2002 16:03:08

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Thanks to everyone for your replies.

 

I should, of course, had said that I have a Ford live axle, with a Quaiffe (spelling?) LSD.

 

With the A-frames bushes so cheap, it can't hurt to change them, and it'll be good practice. I'll try the other suggestions, too.

 

Dave, heavy is a bit of a subjective term I suppose. But the point being I didn't have it before. So, to me it seems heavy My se7en is currently my only vehicle but I'm definately from the Cavalier end of the marketwink.gif

Hope your repairs are going smoothly.

 

Tony, I have two e-mail accounts including my one at work but I can get to them both from home. I thought I included my phone nos in a p.s but I'll e-mail them to you offline.

If you do get a little time sometime, it would be helpful. At the moment I can look underneath and I just see what's there. Not knowing what should be there or how it should appear.

 

Doesn't look like I'll make Aces Cafe on Tuessad.gif

 

Thanks again everyone.

Adil

 

Edited by - adil on 9 Jun 2002 19:24:33

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Ah yes, you did give your numbers, Adil. I'm sorry - I just didn't read it well enough.

 

Not sure I can get to the Ace Cafe either - have half-committed to something else, but am working late anyway so maybe wouldn't get there at a sensible time. Will see how the day pans out...

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James,

 

Thanks I could do with the help. I'll give you a call later.

 

If I get the clunk fixed and find myself a helmet and can get time off, then yes I'll come along to Brands.

 

Adil

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Dampers can 'top out'. This occurs if you've adjustable platforms or posibly if you've got you bilsteins with their circlips which support your non adjustable platforms on the wrong groove. this is especially likely if (like me) you're heavy yourself as you tend to wind the rear ride heights up to compensate.

 

Nigel Mills - 2.0 Zetec carbs

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Well, just to close this thread and so other searchers won't be left wondering...

 

...changed the A-frame bushes last night and all is well. In fact, she hasn't felt so good and "tight" for a long while. Probably since the bushes deteriorated:).

 

Thanks for all the help here and especially to James (aka Jam Mad) for showing me what a simple task it is. Cheers James.

 

Adil

P.S. Of course, today it's raining!.gif

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