Have a 1990 C4

When slowly driving backwards and forwards I get a rear axle (or thereabouts) clunking noise just at it comes to a stop -- both ways.

Have checked all the wheel nuts, the two axle nuts and all rear axle flange bolts (inner only -- cant see the outer ones) -- all tight.

The axle flanges on the side of the gearbox are tight -- although they do have a little sideplay -- but the seal is not leaking so they cannot be too bad.

Questions:

Is any sideplay in the gearbox drive flanges acceptable?

Can the outer CV joint bolts be easily checked for tightness?

Any other ideas?

Thanks

 

If it clunks while turning and is less noisy when going straight, it's the CV joint.

 

Thanks Tom -- but it is the rear so I'm not sure I can test by turning -- and when I hold the inner flange/CV joint firmly with a set of chain grips there is no movement in the joints when you try to turn the wheel back and forth -- no play there.

Copuld it be an engine mount?

A search on the Pelican tech site threw up similar clunking noises whith worn out mounts.

Does anyone have a photo of what a good mount in situ looks like? Mine has about 1/4 to 3/8 of an inch between the mount and the rubber -- is that the nomal position?

 

Try pulling the parking brake part-way and see if the noise goes away. Something loose in the parking brake system could cause your symptoms.

 

Thanks Springer -- that is a good and simple check -- annoyed that I did not think of it myself before I put the car up on jackstands and started to pull bits out -- presently I have the starter motor side half shaft / axle off at the gearbox drive flange -- I'm looking closely at the slight sideplay in that flange.

But looking at the parts book (PET) I can see that the flange is really a very short axle that goes into the differential side gear and that there is no bearing on the flange itself so it must by its design have a little movement -- can anyone comment on that?

Also, last week I did a partial engine drop to change out the starter motor and I had the engine mounts undone on both sides at the rear - but only to drop it about 2 inches to the point where the side oil line stops the engine dropping further -- just enough to get to the top starter bolt -- and that is about the time when the clunking started -- so it could be "connected" -- does anyone have a photo of a good engine mount?

 

Found a picture over on pelican -- yep -- my mounts have seen better times -- so now to replace thm -- then see if the noise is gone -- will report back.

Does anyone know about the side play in the drive flange?


http://forums.rennlist.com/upload/cimg0033b.jpg

 

I get a clunk on mine, I believe it is coming from inside the handbrake assy as all my suspension is new.

 

i used to have a clunk on mine - turned out some part of the rear suspension had been fitted upside down (they used to do it on the 3.2s apparently) and was knocking against the gear box every time i went over a bump in the orad

 

Sure it's not the brake pads moving in the calipers? Mine clunk when I brake at the end of a reverse and again when I first brake going forward after the reverse. Pads being loose and pushed backwards and forwards in the caliper seat. Calipers are due for a re-build soon, so should cure it then.

 

Meek, rebuilding calipers probably will not take care of that knock. Mine are freshly rebuilt, and i get that when I put some pads in, but not when I put others in. I think if you run the anti-squeel spiders, it stops that, but I don't run those either. Also seems that oem pads fit better than aftermarket pads.

Michael, check your rear sway bar liks for play and security? I had a noise very similar to that, and it was one of the links had worked loose where it mounts to the rear control arm. Good luck.

 

I get this sound also. Had my local independent check the noise and he reckoned it was the brakes as you say - he suggested a lot of 964s have this?

 

Thanks Davis and Scott. I will have to see what happens to the sound when I get the brakes overhauled. Atleast they will look prettier.

 

Meek and ScottR -- the pads could be doing it -- it "sounds" to be coming from there -- so I will look at that by looking for play/movement -- and if it is that it would not be a problem long term -- just an "old age noise" but the comment by other poster re different pads perhaps being a different size is interesting

DavisRiley -- the sway bar links are something I had not thought of -- about 4 months ago I fitted a thick adjustable rear sway bar (has transformed the car into a real "fun car" in the corners) and of cours I had the links out for that so I will inspect them closely to see if any movement -- it may be time to upgrade to a nice rosejointed type.

And generally -- I have ordered WEVE black pillow engine mounts so I will leave the car up on stands till they arrive by USPS -- usually 5 or 6 days to hear in Southern Australia.

 

Michael, what rear sway did you fit?

 

Davisriley -- purchased from Performance 9 here in australia -- $325.00 Aus -- made in Sydney by a local springworks -- only know that because when I ordered it was not in stock and then it arrived direct from the manufacturer -- is 24mm with 3 adjusting holes -- tried it in the middle hole first and it's brilliant -- now I only get understeer on slow slippery corners -- in the wet on a very smooth road -- at any quick pace on all corners the front hangs on and when you put the power on all the way through a corner the little C4 diff lock light comes on and the back power slides but only just enough to give you the sensation and not enough to have to correct on the front unless you get carried away -- but it may be I'm not driving that quickly -- just to me it seems quick and is certainly a lot faster through the corners that I could previously acheive with the standard "safety car" understeer. Tyres are Yokahama advan 103's 255's on the rear 225's on the front 17 inch rims Koni adjustable shocks (set exactly mid adjustment front and rear) and H&R green lowering springs but set up high on the adjustments so I don't get clearance problems. Front wishbone bushes purchased from a fellow here on Rennlist -- perfect fit anf quality.