Rear Damper bottom bush MGF.

Having recently had the rear damper off the car i thought I would investigate why the bottom bush so often quickly deteriorates.

First, I removed the inner metal sleeve and measured the bottom fitting on the damper. You can see it is 20mm across.


You can see that the bush within protrudes about 1-1.5mm each side. I also measured a new bush and that is 22/23mm across.

The inner sleeve however is 26mm long:dunno:

With the nut/ bolt/ washers and sleeve I was able to 'mock-up' the actual setup on the car.
I think you can see that the bush can move around when the sleeve is clamped between the two washers.



So even if you tighten it up completely, the bush is not compressed and actually has a couple of mm to move about on the sleeve. Initially I think a new bush will feel reasonably secure, but after a short time the bottom fixing of the damper will be able to move around on the inner sleeve. Result - quickly knackered bush.

Those of us who are F owners will know that this is often an MOT fail. Usually the rears are worse but the same problem applies to the fronts.

I have just had to replace the front bottom bushes after hearing a knocking noise on bumps. Investigation showed the bush had deteriorated enough to allow the damper fitting to hit the inner sleeve. Which is one of the reasons I decided to investigate WHY?

It seems strange to me that the inner sleeve should be 6mm longer than the bottom damper fitting.:dunno:

To me the logical solution is to reduce the length of the sleeve.
So, using a grinder, I reduced it to approx. 22mm. I was careful to clean off any burred metal - we are trying to prevent damage to the bush after all!:yesnod:



I replaced the bush and inserted the shortened sleeve, Then I refitted the damper to the car. The bush is now slightly compressed between the two washers when nut is tightened up. The bottom of the damper is now much more secure.

I admit that until some time has passed I won't know if this solves the bush problem or whether it actually causes other problems, but to make a proper comparison I have modified one front and one rear damper bush sleeve.

I will update this thread as I find out what happens.:bye:

I solved it slightly differently - used Ikea chopping board material and made up a washer up for each side that fitted over the sleeve on either side - has the same effect of squashing the bush. I used the same when I did my rear compliance washers.

AdamElphick;11818 wrote: I solved it slightly differently - used Ikea chopping board material and made up a washer up for each side that fitted over the sleeve on either side - has the same effect of squashing the bush. I used the same when I did my rear compliance washers.

I did consider that solution, but...................... we don't have an Ikea.:dunno:

David Aiketgate;11820 wrote: I did consider that solution, but...................... we don't have an Ikea.:dunno:

No Ikea! how is that possible! There are 3 of the damn places near me - there's no escape down here!

AdamElphick;11845 wrote: No Ikea! how is that possible! There are 3 of the damn places near me - there's no escape down here!

I think the nearest Ikea is Newcastle?:dunno:

Just a quick update.
This modification is showing good results, so far.:yesnod: There is no play in the bottom bushes and the rubbers look as good as new!:woo2:

I have also modified the other two bottom bushes now.

edit:- I can also confirm that although Rimmer Bros, B&G etc only list a replacement bush for the rear damper, the same bush also fits the front dampers. MGR o.e. part number NAM9017

David Aiketgate;11820 wrote: I did consider that solution, but...................... we don't have an Ikea.:dunno:

Why dont you ask Adam to get another chopping board from one of his THREE local IKEAs and send it to you, it is only 3mm thick, i am lucky we only have one Ikea locally (Croydon) and if i never have to go ther again it will be too soon!!!! I too cannot understand why the tube is much lo nger than the bush. can you not get a poly bush for the dampers?? :shake:

Bryan Young;14406 wrote: Why dont you ask Adam to get another chopping board from one of his THREE local IKEAs and send it to you, it is only 3mm thick, i am lucky we only have one Ikea locally (Croydon) and if i never have to go ther again it will be too soon!!!! I too cannot understand why the tube is much lo nger than the bush. can you not get a poly bush for the dampers?? :shake:

Don't need any chopping boards now Bryan!

There are poly bushes listed in Rimmer Bros- part number RNF100090POLY - but at £1.63 EACH I suspect they will be more rubbery than poly-y!:rolleyes2:

That does seem very very cheap for a poly bush, didnt think you could buy a rubber bush for that price???

Bryan Young;14414 wrote: That does seem very very cheap for a poly bush, didnt think you could buy a rubber bush for that price???

Yep, the rubber bushes really are that cheap! And considering that they are a likely mot fail, well worth replacing. As I say, my reduction in the length of the inner sleeve is working well.

And it seems to firm up the handling an amazing amount too. I suppose not having your shocker mounts wobble about would help the handling!

Of course MGR resolved the issue on the TF by replacing the cheap bush on the shocker with a rosejoint type(non-replaceable). So instead of a couple of quid, you need to buy a new shocker!

Glad it's holding up well.... certainly a great tip for when I finally get new bushes... out will come the grinder and Meg will have long lasting bushes.....