clunking suspension

[phatmendus]

I have a problem with noises on my near side rear suspension. I must have litterally spent hours trying to track it down to a specific area but to no joy.

when I have the suspension sitting on the cars weight and push/pull the wheel from one side to the other there is a slight bit of movement. To me this would suggest the rear bearing gone. However if I jack the rear end up and try to replicate this movent it is not possible. The whole wheel and suspension system is solid. The other noise occurs if i push the suspension up and down. It makes a slight clonking sound but again is really hard to track down. I have inspected the whole set up, and compaired it to the other side. There is no visual difference. I have inspected the lotocones as best one can in situ. There is no slack/movement between them and the shocks, and the metalastic bonds look good. I am really stuck about this, I have the MOT tomorrow but am certain they will not pick up any fault. I just need to sort it out for my own benefit rather than the MOT inspectors.

Any advice or experience would be great. If the general opinion is my bearings are shot, and or the lotocones could do with replacing, then what is the best/most cost effective way to do this? would it be to replace the whole bearing assembly or is it better to try and get the old bearing out and just replace this?

The main point is the problem with this clunk and what anybody thinks it may be considering the signs.

thanks

Simon

[ppnelan]

Simon,

Could it be that a damper insert has worked loose in the strut ? I believe that a loose collar/locknut in the top of the strut can enable the insert to move about and make a noise.
I have a similar 'clonk' which I hope to cure when I fit new inserts.

Matthew

[phatmendus]

I have checked those top nuts and they are both very tight. That was my first thought too, but it must be something else. I even thought it was the wiring loom knocking at one point (sheer desperation!)

Thanks for your thoughts anyhow.

Simon

[tdafforn]

The MOT should certainly pick up if the rear wheel bearings are shot, they did with me...
Replacement is a bit of a faff, particularly getting the hub off, I got Paul Matty to do mine, and even with the proper kit it needed the use of a gas axe to warm 'em up a bit!
Re: thumping at the back..
Check the Lotocone, on my +2 the metal insert on one lotocone had parted company with the rubber! The MOT didn't pick this up, but it was potentially lethal! Otherwise, what exactly do you do to get the noise?
Cheers
Tim

[phatmendus]

Hi,

I have checked the lotocone as best as I can in situ, and it looks/feels pretty good really. The noise is a difficult one, as it occurs obviously when driving over bumpy ground, even VERY slowly. Its a loose clonking/rattleing sound somewhere near the suspension. However when stationary, whatever I do I cannot replicate the sound. Now comes the other part...... Due to my many hours of inspecting I have noticed this slight bit of movent of the wheel in the horizontal plain i.e push/pulling the wheel in/out. This only happens when the weight of the car is on the suspension. If I jack it up and wobble the wheel the same way the whole system is sold and movement is not possible. The last point to note (and this too may be seperate) is if I bounce up and down on the suspect side of the car The shock makes a slight clunking sound as it returns back to its normal positon. This sound is totally different to the rattle sound which is only heard whilst driving.

I have checked and tightened the retaining nuts at the top oif the shock, and there really is no obvious loose movement in the verticle plain

Im sure there is a problem but i need to track it down to be able to replace whatever is wrong.

Cheers

Simon

[wildoliver]

my money is on the strut insert, drop your strut off (dead easy, spring compressor, top shock nut and bottom wishbone bolts, rotoflex and caliper) and take the strut insert retaining cap off, i bet either the caps loose or the O rings around the strut insert are perished and are allowing lateral movement inside the strut.

[phatmendus]

Sound like a good possibility.

If thats the problem what is the best course of action? Are the shocks salvagable or do people recommend getting hold of some more modern shocks? If so what and where?

Also any idea on why I can get some movement horizontally (very slight) when weight is on the car, but not so if I jack it up?

Simon

[Roy Gillett]

Hi Simon,

I am not sure if what I am going to suggest fits the nature of the noise that you describe. I had a real rattle from the rear end over bumps that I could not get the suspension to replicate standing still.

I finally tracked it down to the handbrake calipers rattling because they were so slack when going over bumps (especially speed bumps!). I found that if the handbrake was pulled on the rattle went away (Don't worry it has little effect on your forward motion!). Rebuild the calipers (Classicar) noise disappears.

Just a thought.

Roy

[phatmendus]

Dear Roy,

That sounds like another really good idea. I shall have a look this evening. Although the handbrake operates fine I did notice that it has a lot of movement around the back joint.

Thanks for the tip.

Simon

[wildoliver]

I hope it is handbrake!!!!

Yeah you can rebuild the inserts, i'm actually going to start supplying reconditioned ones shortly.

[gjz30075]

Simon, I remember your previous post on this. You may be at the point of a complete tear down of the rear corner to find the noise. I'm starting to put my money on the hub bearings or a bad shock/damper. The in/out movement of the wheel bothers me. Shouldn't be there. The hub could be worn to the point of allowing the bearings to move about.

Greg Z
'72 Sprint

[Hamish Coutts]

Another thing that can cause wheel movement is a worn outer driveshaft.
This is where the outer diameter of the driveshaft is slightly less than the inner diameter of the wheel bearing that supports it. In effect the driveshaft is a 'rattle fit' in the bearing.
My +2 had this problem which was picked up at the MOT when the mechanic jacked up the back of the car and shook the back wheel. There was a fair bit of movement - and clunking. The movement and noise was still there with the car back on the ground but not as much. I've got TT driveshafts fitted but if you had doughnuts I would think that the spring in the rubber would effect the amount of free play mentioned above when the suspension angles were changed by jacking up the car

BTW - It turned out the driveshaft was a loose fit in the outer wheel bearing. The inner wheel bearing was acting as a pivot.
I suspect that the PO had a wheel bearing seize at some point which damaged the driveshaft because it was badly grooved. The cheapskate probably just fitted new bearings and ignored the driveshaft damage. I fitted a new driveshaft and bearings - no more problem. Also a local engineering company offered to metal spray the driveshaft and grind it to the correct diameter but by that time I had ordered the new stuff.

Hamish.

[tdafforn]

Interesting,
I have exactly the same sort of thing on my +2 which has brand new dampers and a completely refurbished rear suspension.
In the end I discovered that it was only when there was nothing in the boot and only me in the car..(ie the back end was light)
I think I have tracked the culprit down to the droop limited shocks that I have fitted hitting the stops at full extension.
This may be made worse by them not being set to a high enough damping setting..
Cheesr
Tim

[phatmendus]

All useful comments. Thanks for the info. I to think that a total stripdown may be the answer.... bugger.

On a good note, I have just returned from the MOT station as well as the DVLA office. The car was passed with no problem noticed, I then managed to beat the que and got my free (ah so sweet) tax disc, and yes.... the lotus is back on the road after 13 years in bits, in storage!

All good, but my clunking still bothers me even if it doesnt bother the MOT man. I think a suspension strip-down and rebuild is the plan. At least it will give me something to do now the rest of the car is finished!

Simon

[type26owner]

If the axle has failed it's due to first corrosion fretting and then the advanced stage is called creep. Creep is when a deep groove is worn into the axle underneath the bearing race. Usually the outboard bearing has the problem happen under it. You can tell if this has happened by having someone else yank fore and aft on the wheel while it's resting on the ground. You must get around behind and feel and look for any motion between the hub and the strut housing. The donuts are so stiff you can't do both tasks at the same time by yourself unless you're Superman. This test takes 5 minutes to do both sides tops. There should be no detectable motion. There will be no in and out motion either unless of course the outer race of the inboard bearing has destroyed the fit of it into the strut housing. There is a large retaining ring that goes into a groove in the strut housing which holds the bearings in both sides. All this stuff is subject to SEVERE fretting damage. Loctite is the only save your arse bigtime option there is.