Front shock absorber play
 

For some time I have noticed a quiet knocking noise from the front suspension when going slowly over small bumps. It is intermittent and not very noticeable.
I can sometimes reproduce the noise when lightly bouncing the wing.

Investigation shows that is NOT:

bottom ball joint
wishbone joints
track rod ends or steering rack
anti-roll bar bushes or links
strut top bearing

I am concluding that it must be end-float in the shock absorber insert inside the strut, secured by the gland nut, or else an internal play inside the shock absorber itself. The shock absorber seems fine - it damps a bounce immediately, and it is not leaking.

I know it is possible to release a strut at the top, compress the spring, release the top nut, unbolt from the turret, lower the suspension, and swing the strut out from under the wing and then remove and replace a shock absorber after undoing the gland nut, because I have done that in the past.

My question is, would it be possible to a) tighten the gland nut if it is loose, or b) undo it completely and slide it up the rod, without any other dismantling?

If there is any float caused by the nut not fully locking the shock absorber, I am wondering whether I could simply cut a metal shim with slit and spread it over the top of the top of the shock absorber, and then retighten the gland nut?
Has anyone ever done this? Does it sound feasible?

Update:
Yes, it is possible to undo the gland nut without any other dismantling, so I could quite easily have added a shim on top to clamp the shock absorber better inside the strut tube.
My idea had been to make a thin shim out of lead roofing flashing, cutting a hole and a slot to get it round the rod.

However, investigation shows that there is a tiny amount of end play in the rod itself, presumably at the piston end inside the tube.

My question is, does this matter?
It doesn't affect shock operation, steering, or wheel alignment, so my inclination is to leave it and see whether the MOT tester thinks it matters or not.
Any opinions?

If you can feel that wobble pulling on the wheel then it is time for new front shocks

There is no wobble, either at the steering or at the road wheel. The only play is a tiny up and down end-float in the piston and rod inside the shock absorber, measuring about 10 thou.
It really only does it when cold, in the first few miles. After that it is barely detectable.

Update:

Passed the MOT this morning.
The tester gave it an advisory because of slight oil misting round the top of the shock absorber. That will be the PlusGas I squirted to free the gland nut so that I could check it was really tight. :)
I'll degrease the shock absorber and then see if it is really leaking.

No comment on the play, which has virtually vanished with time and warmer weather.

Hi Clifford,

It's funny, I've been trying to track down a slight, erratic knocking from my front left side. You can sometimes reproduce it by pulling the top of the wheel. I can't find anything visible wrong, so was starting to think along your lines of the bottom of the damper moving inside the strut.

I fitted these dampers about 8-9 years ago, and seem to rember a rubber cushion at the bottom of the strut, is this correct? Could that have broken up?

Thanks

It's a steel ring.


I have seen insulation tape wrapped around the bottom of some 240 front shocks , likely to solve such knocking noises.

If it is the damper inside the strut then as I discovered, you can undo the gland nut without any other dismantling, so you could put your shim or insulating tape etc on the top of the damper and then do the nut up tight.


Hold the rubber boot up out of the way with a stick, and put a C-spanner or wrench through the spring, or use a blunt cold chisel.

So what happens to the steel ring? Is it not fixable or replaceable?

Nothing happens to the steel ring, never seen a broken one