Annoying rattles at the rear.....Any ideas????

[Piet]

I have been hunting these down for a while but to no avail. On each side of the car, below the rear seat, at about where the rear suspension mounts are, are two seperate rattles driven by road surfaces. They are coming from below the floor (confirmed by trusty sidekick lying on boot floor as we drove around). Various testing done with bits in the rear removed, so we know its not the seat, seat belt mounts, boot lid. I've been underneath to check the petrol tank bolts are done up. They are fairly high pitched, around 10-20 Hz. They don't sound like serious heavy duty suspension clonk like what you'd expect from worn bushes.

Any ideas????

 

[Andy McGhee]

Could it be coming from the bolt through the shock absorber eye?

 

[angel]

Worn arm bushes give sounds that range from creaking to clonking according to my experiece. Inner ones are the most suspect for noises as you can't see what's going on with them. Outer ones will usually first visually fail, then audibly.
Don't overlook both shock absorber fixings, as Andy pointed, though.

 

[sdvcatfish]

Not quite the location but I have a Rattle which sounds like it’s the Rear Suspension.
Turns out it is the seat Belt Reel/Spool. Pulling it to its full extent makes it disappear.
Just a suggestion.
Ian. (1987 4F4).

 

[Piet]

Thank you all gentlemen! We have an answer. It seems to be principally inner torsion bar bushes with a small side helping of front shocker eyes. I initially dismissed bushes out of hand because I had had all the rear torsion bar bushes replaced- or so I thought!

I started out jacking up the car and removing the LH rear wheel. Just moving the suspension arm up and down resulted in high pitched creaking so I initially did up the front bolt and nut and the rear mount nuts. They were pretty tight already, and no real change. Then I partially removed the front shocker bolt and greased under the head and tail and the washer with rubber grease and did it up again. This has helped with fretting in the past. I have fairly new de Carbon/Delphi shocks at the rear and this puts a lot of load on these joints.

While I was feeling around and bouncing the hub up and down I held my fingers at the interface between the torsion bar and the bracket where it goes through the inner bush- perceptible relative movement! Very disappointing, these should have been changed along with the outers. Mind you that was about 12-15 years ago so maybe they have just failed.

Anyway, I squooshed (technical term) as much rubber grease into the gap between them around the torsion bar on the inside face of the bracket. Moving the hub I could feel the grease slurping in and out as I did so.

Took the car for a drive and noise stopped on that side. Repeated for the RH side except didn't bother with the front shocker eye. Another drive, mostly all the noise gone, so I'll go back and do the eye, but in the longer term it looks like I'll need to do bushes.

The same garage chickened out on doing the front torsion bar bushes (one of which has been clonking for a while), so I will likely be looking at having to tool up seriously with all the gear for changing them.....

 

[Piet]

....And going back to previous posts I found one from myself where soon after the bushes were "changed (????)" I applied rubber grease.

But this raises the next question, for when I eventually do something and change the inner bushes- nowhere can I find any reference to lubing the metal-to-metal outer sliding interface on these bearings- not in MR61 or any of the other manuals I have looked at. That seems crazy. Rubber grease may not be the best thing to use (I don't know if its hydrophilic), maybe a rubber-friendly silicone grease like BR33 would be better, but surely we should be using something????? Has anybody ever done this?

I know, Pierre Dreyfus will be rolling in his grave muttering, "PAS de graesage!!!!"

 

[angel]

There is no metal-to-metal contact or sliding on these bushes. Not even rubber to metal sliding, because they are "flexibloc" bushes, this means outer sleeve vulcanised to rubber bush that is vulcanised to inner sleeve. Movement is achieved by the rubber part flexing. That's why it's important to fit them at the specified position (roughly at the middle of suspension travel), otherwise they will get unduly stressed and fail prematurely. The same goes for front suspension bushes, all fixing bolts must be tightened with suspension compressed to specified height. That's how "pas de graissage" became possible ;-) .

 

[Piet]

Thanks Angel- Interesting! Given they are so thin the two thin bush sections must be fairly marginal in torsion. I assume the fat section gets clamped between the two inner brackets on each side?