Rear Suspension Banging

[Goss]

Hello Chaps,

I have a banging sound from the rear of my MK2 but only when there is no one in the back of the car, sounds like the exhaust banging but checked that and all is well. I have been told that the centre spring rubbers are a known problem for wear so have ordered some seeing as mine are over 18 years old.

My question is how easy is it to replace them? I am hoping its a case of taking some weight of the springs and undoing the clamps.

Regards

Goss

[PPV]

It could be the panhard rod rubbers. Mine were soft and worn when I got the car and gave a banging sound. They were straightforward to change. Not quite sure what you are referring to with the centre spring rubbers but presume it is the rubbers holding the cantilever springs in the middle. If they are gone I would suggest looking at the other rubbers at the front and rear end of the springs and also the torque arm bushes and those for the shock absorbers. I found them all reasonable easy to replace but obviously you must unload the spring before working on it. If it is the panhard rod then when bushes replaced you need to check that the wheels are equidistant from the spring mounting plate. The manual covers this well.
Regards,

[340jag]

It's a long Job , so I would say a winter one , I made my spacers out of polycarbonate ,nothing left of some of the rubber ones .
Your be lucky if you can re-use the tubes and bolts, I replaced with s/steel .
I gave my leafs a coat of chassis black , then loads of wax oil , mixed with old engine oil , to keep things moving !
Good luck .

[Martec]

May I suggest that instead of asking what it might be you jack the car up and LOOK and use a big screwdriver to see what moves about, I'm sure your mechanic will do the same.

Changing the centre spring pads requires most of the suspension to be dismantled to releave the spring pressure. About two days to do it in your own garage, you will need axle stands and a good trolley jack to raise and lower the spring ends into place. I have to replace them about every 4-5 years, considering polybush pads next time and rubber in the spring eye.

How good are your shock absorbers, they also act as the limit of droop for the axle and so springs. Using a trolley jack you can lift and drop the axle to find the knock, cheaper than substitution.

The spring boxes and panhard rod bracket are good at rotting after 50 odd years, worth a good broddle with that big screwdriver!

Brian

Try kicking the tail pipes, it could be something a daft as a poorly positioned exhaust or a broken mounting? Hence my first sentence.

[Goss]

Thanks for your replies, there is no movement in the panhard rods they were rebuilt in 1999 (12,000 miles ago) and still look like new and they were the superflex bushes too. The underside of the car looks like new and has no rust, the shell is a Californian import and the only replacement panel from new is the transmission tunnel (taken from the original UK car) where a big engine/transmission was fitted to the car in the USA.

Will get under there again and have a good prod with a screwdriver, my MOT man says he would spot anything like panhards etc but would not spot the centre spring rubbers so may take it to him on Monday to check whilst on his lift.

Brian you replace every 4-5 years? Is that normal wear?

Regards

Goss

[Martec]

Those spring pads are the only thing holding the spring in place, the torque arms take alot of the force of braking and acceleration but you CAN see the state of the rubber pads from the wheel arch with the wheel off or just forward of the wheel. If I see cracks in the rubber then I replace them.

I am getting tired of the job, so have decided to replace the centre pad with the poly ones I've had for a while, but replace the poly spring eye bush with rubber so as to give some rubber insulation between the axle and body.

Rubber doesn't last long in high stress situations thats why I have 80+% poly in my suspension, but rubber in 20% to give NV insulation.

This is from my own experience of driving and maintaining the car for 17 years and seeing rubber collapse in the high stress wishbone bushes and torque arm bushes, some within 2 years. Possibly because I have proper brakes that allow me to enjoy driving it in modern traffic.

Brian

[piman]

Hello all,

it is generally not recommended to use stainless steel fasteners on safety critical areas as they are rather brittle. I have found over the years that using copper slip grease with mild steel (8.8 grade) fasteners does allow easy disassembly many years from original assembly.

Alec

[340jag]

Have a look on E-bay Alec , your find 1000's of calliper bolts in s/steel !!!

[Martec]

This post seems to have moved on to Caliper securing bolts, so may I add a few comments to add to the confusion.
Many years ago after having completely rebuilt my rusted wreck and uprate the brakes I secured the caliper mounting bolts (MS) with loctite, on the M6 a bolt came out and with difficulty we stopped. I found all the bolts had worked loose.

I went to a local bolt supplier as I wanted to replace them all with high tensile and then drill and SS wire them in. It was pointed out to me that the one remaining bolt in the offending caliper had bent, not sheared as it probably would have if it was HT, he recommented that I continue with MS, and wire them in.

15 years down the line they are still in use and are copperslipped and have come out easily after I have cut the wires. Mild steel is strong and ductile, bends rather than shears.

Brian

[340jag]

Yes sorry for the diversion , I was just pointing out that s/steel bolts are used and sold for safety critical areas !
The s/steel bolts in my pic are not under load as such , they just keep the long springs in line
A friend of mine raced motorbikes , he had a front disc bolt snap off , that was made of titanium !!

I do find that the original Jaguar parts are of a much better quality , most of the new stuff comes from questionable places !

Back to the job in hand , once the axle and springs are removed , you can get in there with the wax oil

[Martec]

The good thing about forums like this one is that everyone has something to contribute from their experience and technical knowledge.

As far as SS is concerned it is a term that covers a very large scale, from my British steel apprenticeship days of 18/8 for cutlery to chrome moly Van tubes that were used in some industrial applications, I'm sure there is a suitable 'ALLOY steel' that would do the job but it needs to be ductile as well as none corrosive, as you say we have a fair idea where this stuff is coming from but the quality is questionable!

Just to touch on wax injection, really these cars should never go out in the rain! (that should get the post coming). if you jack a MkII up and climb underneath you will see a series of great gaps between the floor and the chasis rails and no holes in the bottom of the rails, the rear box sections, jacking points are worse with huge holes high up and no drain holes. ie water is encouraged to enter but can't get away.........it rots out!! After market sills don't have the drain scallopes in the inner sill to let water out.

I sealed all high level holes with steel or seam sealer and drilled 1/2" holes to drain it then wax it every 4 years with Dinitrol, filthy job but better than replacing steel. We always do the water splash on Rallies.

Brian

[340jag]

I can remember bunging up the drain holes in the sills to stop the waxoil mixed with oil from running out , with plastic , plastic is still in the sills some 35 years on !
I see a XK8 last year , for £1900 , wanting new floors and sills , the rot never stop's !!

[piman]

Hello 340jag,

I hardly think that E-Bay is the best referenece for what is suitable and what is not?
Funnily enough this is taken from E-Bay:-

Stainless steel bolts are stronger than ordinary steel bolts
This is clearly not true for the majority of stainless steel bolts. Stainless steel in general has very little carbon, and because of that, most grades of stainless steel cannot be hardened by heat treatment. Stainless steel bolts are, in most cases, just slightly stronger than Grade 2 hardware store junk bolts, and in nearly all cases, significantly less than Grade 5. You do NOT want to use common-grade stainless fasteners in any application that would call for a hardened (Grade 5 or Grade 8, or stronger) fastener. ARP makes a fine line of stainless bolts that have a tensile strength of approximately 170,000 lbs per square inch. This is greater tensile strength than a typical Grade 8 fastener, but keep in mind that tensile strength is not the only measure of bolt quality/strength. Common grades of stainless steel may have reasonable tensile strength, but significantly less yield strength than a "regular" steel bolt--the stainless bolts are more "stretchy". Those ARP-made bolts are the ONLY stainless fasteners I'm aware of that are suitable for general use. There may be others--if you know of any, please let me know!

Also remember that stainless fasteners are more prone to galling which seizes them solid. If you use stainless fasteners, lubricate them before assembly.

Alec

[340jag]

If you plan on doing the job Goss , I found a small trolley I made to move Engines about very handy , you can drop the axle on it , and roll it out , then back in when the job is done .
It's a job to know when to stop , as the axle is out , you may as well rebuild that , the jobs are endless lol
Ps I never used stainless steel bolts on the trolley wheels for safety reasons

[Goss]

Thanks for all replies, for some reason the auto notification on here only worked for the first post?

Had my mot man check the rear end out but no play found, exhaust not banging and shocks seem to be fine, very odd. We noticed that the springs could do with some lube but just a maintenance issue.

The car was completely rebuilt 12,000 miles and 17 years ago so I'm hoping its down to rubber that has perished somewhere but finding it seems to be harder than we thought. Next step is to empty the boot including spare wheel and cover to eliminate them.

Regards

Goss