21 replies to this topic

[TiMtImInYtImTiM]

Hi all, a bit of a funny one this and need your help. We have a Cooper Sport 2000 MPI. I have not posted this in the MPI specific area as this may not be an MPI specific issue.

 

Over the weekend I took him for a drive down some country lanes. It normally get used to commute to work and back so a little more stress than normal but nothing the car shouldn't be able to laugh at. 

 

30 minutes into the drive I noticed a rattle and then a knocking coming from the nearside rear. It had new GAZ adjustable shocks on the back a few thousand miles ago. After investigation I determined that the shock had become lose. I attributed this to the fact that they were new, the rubbers had compressed after some miles creating the gap and the knocking was coming from the shock moving in the mount. The country lane drive obviously making the knock apparent after the added stress.

 

So I limped him home and dropped the tank to investigate. As expected the shock was loose enough to move by hand. I managed to get the shock as tight as I could get it using the nut on the top and the nut in the wheel arch at the top of the shock. I can only assume that the thread had become damaged whilst it was lose as getting it tight was a real struggle. 

 

Driving it to work this morning the knock is still there although it has improved 50%, I cannot get the shock any tighter, do the rubbers need replacing/packing out?

 

The rattle is also still there. It definitely sounds like it is coming from the wheel arch. Like a wire is rattling or something. I cannot Identify what is causing the rattle.

 

Help!

 

[cal844]

Change the shjock, my friend had the same issue with a brand new Gaz adjustable, he ended up sending both rear shocks back as both were banging as there was no bump or rebound resistance

Edited by cal844, 14 December 2015 - 10:41 AM.

[Cooperman]

Maintenance Tip:

 

If you want better access to the LH top damper mounting to avoid having to pull the petrol tank out of the way, cut a rectangular hole in the vertical rear seat panel, about 5" x 3" and fit a cover plate made from 1.2 mm aluminium secured by self-tapping screws and bathroom sealant. That way you can remove the damper, or tighten it, very easily.

Photo shows exactly where to cut. This was/is done on every rally car to enable dampers to be changed during events.

 

[TiMtImInYtImTiM]

I'll take the shock off and check tonight I think. Just in case it has failed.There definitely seems to be rebound. Doesn't explain the rattle though? 

Edited by TiMtImInYtImTiM, 14 December 2015 - 01:25 PM.

[ChopperHarris]

Drive it without the shock to test (within reason)
Rattle, probably something rattling ;o)

Seriously though jack etc?

[TiMtImInYtImTiM]

As long as the shock is returning ok, I cant see it being the that. I am trying to think of what might be in the wheel arch area that could be causing the rattle. Its odd that they started together so it does point to being the shock. But do shock absorbers rattle? 

 

Are there any cables or brackets inside the car that could be causing the issue? I have had the plastic door bin cover off and checked in there. Nothing loose or that could be causing a rattle. Definately sounds like it is in the arch, but there is nothing to rattle...

[firstforward]

I had the exact same thing with a Gaz shock, had to be the tank side also, the shock itself was working correctly, if you play about with adjusting the rate I was able to find a "quieter " position but it was always there. Trouble was I had the shocks for over a year and so no warranty even after contacting Gaz.

[TiMtImInYtImTiM]

I had the exact same thing with a Gaz shock, had to be the tank side also, the shock itself was working correctly, if you play about with adjusting the rate I was able to find a "quieter " position but it was always there. Trouble was I had the shocks for over a year and so no warranty even after contacting Gaz.

 

Did you have a rattle and a knock? 

[sledgehammer]

years ago had a bumper bolt loose - that had us puzzled for a while

 

rattled like hell over pot holes , but not when bouncing the car

 

another possibility if it isn't the damper , is something in the tank usually a rattle when pulling away / stopping

 

as above take the damper of - gentle slow drive over pot holes with someone in the back

Edited by sledgehammer, 14 December 2015 - 02:40 PM.

[TiMtImInYtImTiM]

years ago had a bumper bolt loose - that had us puzzled for a while

 

rattled like hell over pot holes , but not when bouncing the car

 

another possibility if it isn't the damper , is something in the tank usually a rattle when pulling away / stopping

 

as above take the damper of - gentle slow drive over pot holes with someone in the back

 

I am concerned about driving the car without the damper on. Surely the wheel will just collapse up into the wheel arch?

[nicklouse]

gaz shocks are not the best out there. sounds like it has failed.

 

why would not having a damper fitted cause the car to collapse?

 

a damper does not hold the car up it dampens the motion of the wheel and it sounds like it is not doing so.

[Cooperman]

 

years ago had a bumper bolt loose - that had us puzzled for a while

 

rattled like hell over pot holes , but not when bouncing the car

 

another possibility if it isn't the damper , is something in the tank usually a rattle when pulling away / stopping

 

as above take the damper of - gentle slow drive over pot holes with someone in the back

 

I am concerned about driving the car without the damper on. Surely the wheel will just collapse up into the wheel arch?

 

It's the rubber cone spring which controls the ride position of the wheel. The damper, as the name might suggest, 'damps' the bump & rebound rates of the spring. Remove the damper and drive the car over some bumps. The back will bounce a bit more than usual, but you'll be able to hear any knocks or rattles.

[sledgehammer]

Have you fitted coil overs (coil & spring in one) ?  -  if so don't take it off

 

if normal rubber cone spring in subframe you will be fine - as above the cone supports the weight

 

the damper suppresses the bounce

[firstforward]

 

I had the exact same thing with a Gaz shock, had to be the tank side also, the shock itself was working correctly, if you play about with adjusting the rate I was able to find a "quieter " position but it was always there. Trouble was I had the shocks for over a year and so no warranty even after contacting Gaz.

 

Did you have a rattle and a knock? 

 

 

No it was just a knock, it first started at very low speed turning left into a junction, when the wheel was unloaded, as time went on it happened all times on rough surfaces BUT it was not there at speed above 40mph.

Edited by firstforward, 14 December 2015 - 06:04 PM.

[sledgehammer]

just a thought - give the radius arm a quick grease ,

 

check the mounting bolts & subframe mounting bolts while you are in the area

 

a dry / worn knuckle joint can give weird noises some times as well