Car going bump

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markhowes
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My G is a 1993 300GE Petrol SWB

Recently noticing a bump from the offside rear when going over even quite small road imperfections. Garage had it up on a lift - checked exhaust and other possible culprits but found nothing obvious. Then we figured that maybe it was the offside rear shock absorber.

Back on the lift and mechanic swapped the rear shock absorbers over but the clunk was still coming from the offisde rear. Cleaned up and checked both rear springs but they appear normal.

He came up with this - I'm not actually sure what it's showing but could this be the cause?

If not, any other ideas before I stump up for a pair of shock absorbers and springs (not cheap).

 

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Pistonhead
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Re: Car going bump

That seems to look like the end of shock absorber but if these were swaped then the noise should have transfered in theory.

My other thought turns to the brake limiter valve; is that secure or is it's control rod attached to the valve end and, or the diff end. 

What are the shocker absorber (s/absorber) bush ends like? Disconnect one s/absorber one at time and between each do a short road test to confirm. 

If your mechanic has "Chassis ear" kit, the job is easier to diagose.

Note: some W463 are now known for the coil spring mounting to corrode, are you mounts O.K. or with a hair line crack developing?

markhowes
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Re: Car going bump

Thanks Rakesh,

Checked out "chassis ear" on ebay and Amazon. That looks a great bit of kit and if it wasn't over £300 I'd invest in one.

I guess my garage probably doesn't have one - he certainly didn't mention using one. But he has had a really good look around the rear suspension, prolific use of air hose and wire brush with no sign of excessive rust or hairline cracks.

Bushes all seem pretty good - the sound we get is much more of a thump rather than what I would expect from just worn shock bushes. I originally thought it was the silencer box that goes across the rear of the vehicle in front of the petrol tank hitting the body above but I can't get it to move anywhere near enough no matter how hard I try move the pipework.

I'll carry on thinking - I really don't want to spend over £500 on new shocks and springs only to have the noise stay.

 

Rowland Kenny
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Re: Car going bump

You might like to check the rear door guide is adjusted up enough. It can often wear or drop a bit when the door opens and shuts and when it does you get a dull thump over bumps in the road. Obviously the door plus spare wheel is very heavy and the hinges can wear a bit as well. Adjust up the guide and see if that does the trick.

Regards,

Rowland Kenny

markhowes
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Re: Car going bump

Thanks Rowland.

Funnily enough, when I first heard it I did think I hadn't shut the rear door properly (but I had). The door does seem pretty OK - no obvious droop when open or up and down movement but now that you've suggested it, I'm going to have a better look and maybe take off the spare wheel to see if that makes any difference to the sound.

 

 

markhowes
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Re: Car going bump

Ha!! I do believe that you're right. I wedged a bit of towel in the bottom of the door, drove over out potholed track and the noise disappeared.

Now I just need to work out which bit I need to adjust (or replace).

When you say the "door guide" do you mean the plastic piece on the door frame or the metal piece on the actual door. The plastic piece looks as though it will only adjust backwarsd and forwards and the metal piece only up and down.

And is it just a matter of trial and error as far as adjustment is concerned - move it by 2mms and then see if clunking has stopped?

Or might the plastic piece have worn down after 28 years so needs replacing?

Keep the advice coming - very much appreciated as I was on the point of ordering a new set of shock absorbers and springs at horrible expense.

Rowland Kenny
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Re: Car going bump

 

Hi Mark, glad you found my suggestion helpful re your bumping door. I have only adjusted up the metal guide to cure the noise and find I need to redo from time to time as it’s difficult to get it tight enough to withstand the doors’ weight for long.

Anyway I hope it has saved you any huge expense!

Kind regards.

Rowland Kenny.

markhowes
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Re: Car going bump

All cured now.

On the hinge side of the door - above the top hinge is a short post that locates into a hole in the door frame when closed. That hole had some debris in, presumably from closing the door and trapping some overhanging foliage. I cleaned out that hole and put some vaseline in the hole and on the post. Problem solved - no clunking.

How bizarre is that?

For good measure I've also changed the plastic door supports (down near the bottom of the door and frame below the door latch) the design has changed since the originals. Cost £42 from MB

All good now.  And to think, I was about to spend nerly £1,000 on new shock absorbers and springs.surprise

jdring
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Re: Car going bump
Just thought to say I had this on two 460s I have had and made the door close tighter to stop it. I thought that some rubber buffers would work too, to stop the rattle.