Activa Ram Bush MKII Made and Fitted

[CitroJim]

My local stealer has, so far, been unable to supply me with a replacement bush for my rear Activa Ram.

I made a rough one out of a bit of nylon I had knocking around and this worked for a few weeks. Gradually though, the noise, akin to a duff drop-link, returned and today I made a MKII version of my bush.

This time I used a material called Nylon 66 and selected a Moly (Molybdenum) Filled type. This was recommended as being machinable, hard-wearing and indeal for the manufacture of bushes.

I looked at the old bush I made and I realised I had made it a rather loose fit originally so with the new one I made it an interference fit into the ram eye and drilled the central pivot hole very tightly. I also made it a tight fit into the yoke on the suspension arm where the ram eye slots into.

You can just see the bush in this picture:



I'm pleased to report that this bush is working rather well and has silenced the rear perfectly. I went out and found the roughest roads I could as a test. It is amazing just how much racket just a tiny bit of play in this bush creates

How long it'll last is another matter

I'm not sure if the system will suffer in any way having a bush made of a harder material than the original which is a metal-rubber-metal bush of the conventional sort. I guess any shocks in the system will happily be absorbed by the Activa Balancing Sphere but I do wonder why Citroen chose that kind of bush in the first place.

I have loads of raw material so if any fellow Activa owners want to try one, I'll be happy to make some. This time I made a careful note of the dimensions of the finished bush.

Finally, a shot of the bush being made...



What's the betting the stealer will call me in the morning to tell me the bushes are in

[AndersDK]

So now the standards for owning and driving a Citroen has yet again moved up a step : you've got to own a lathe

[fastandfurryous]

It's really nice to see that people do still make bits to fit their car. I was beginning to think I was the only one.

The sense of pride you get after fitting something like that and finding it works is even greater than just fitting off-the-shelf parts I find.

Good job!

[jeremy]

It could be that polyeurethane is the material you require. I know that the 4 x 4 brigade swear by them but in truth they are probably noticing the difference between worn out bushes and new ones but there could be something in it.

It may be that someone already makes one to the required size but manufacturers like Ploybush only list the things against specific models like Impreza's rather than by size which would enable others to use them if the sizes matched.

[CitroJim]

It could be that polyeurethane is the material you require.

Thanks for that Jeremy. I had a look at the technical specs and it is certainly a more suitable material than Nylon 66.

After reading about it's properties a little more closely, I'm not expecing the Nylon 66 bush to have a very long life, especialy when winter hits with cold and wet salt! Still, if nothing else, the concept has been proved.

I've discovered a material called Tufset Tufnol which is a machinable polyurethane supplied in rod form. A few of the improvements over Nylon 66 is that it is very tough, has a bit of give in it, is not affected by moisture or temperature and is resistant to just about everything. I understand it is very similar to the stuff skateboard wheels are made of. That give me an idea...

The downside with the poly rod is that from RS Components (the only samll-volume suppier I can currently find) it's a bit pricey at £26 per metre for 25mm rod. Mind you, that'll make a lot of bushes.

I've thought about the poly bushes advertised for certain classic and performance cars and they would seem ideal. It all depends if any of them are willing to see if they have anything close to the size needed. Of the ones I've seen, they're not cheap and make the cost of a metre of Tufset rod look quite attractive.