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Lower rear radius arm improvement Dolomite

Posted: Tue Feb 11, 2014 8:26 am
by Reme5969
I need to get feedback from members who have experience of failure of the rear lower radius arms on the Dolomite. I know most people are aware that corrosion is a big problem and can lead to failure.

Ignoring the failure due to corrosion for the time being, where are the main areas where the arm is failing, i.e. Where does it need most additional strength? Obviously, certain dimensions cannot be changed, distance between centres of fixing points, fixing point of lower shocker, width at fixing points.

An increase in thickness of material used is an obvious fix but that alone would still leave it prone to stress fractures transmitted through the use of poly bushes. Unless we accept that metalastic bushes need to be used in the fixing points and discount the use of poly bushes at these points.

Anybody any thoughts on this matter?

Also, can anybody assist with an engineering drawing of the offending item showing dimensions that can be used to take to engineering co's with a view to designing an uprated strengthened version? Jez.

Re: Lower rear radius arm improvement Dolomite

Posted: Tue Feb 11, 2014 8:42 am
by Toledo Man
As far as I'm aware, Polybush and Super Flex should be fine. I wouldn't fit any other make of bush. It is worth looking into and as you've already mentioned, certain dimensions are fixed but anything that has been created by man can be copied (and improved).

Re: Lower rear radius arm improvement Dolomite

Posted: Tue Feb 11, 2014 9:52 am
by DF
Also I found when lowering springs were fitted to the car the back of arm axle end hits the welded bracket
On the axle tending to rip the part just in front of the bush
I just remove 5 mm tapering it out to the top
No more rub marks were found on axle bracket when inspected .

Re: Lower rear radius arm improvement Dolomite

Posted: Tue Feb 11, 2014 10:36 am
by Reme5969
It is details like that that i need to know as that particular part can be factored into a new design. Jez

Yes..

Posted: Tue Feb 11, 2014 10:50 am
by sprint95m
Reme5969 wrote:Anybody any thoughts on this matter?

Also, can anybody assist with an engineering drawing of the offending item showing dimensions that can be used to take to engineering co's with a view to designing an uprated strengthened version? Jez.
This question may be worth asking in the Motorsport section of the forum....?


It may be worth contacting LLoydpiestate from the T2000 register. He is commissioning panels for 2000s. These are made using scans of an original panel......
(Scans are over £600 each for said panels.)
http://www.triumph2000register.co.uk/ph ... 2&start=80

I am thinking he will be able to point you towards helpful companies thereby saving you some unproductive running around.....?




Companies such as Rally Design sell tubular arms but I have no experience of these so cannot comment about employing these on a road car.
Ken wood has this type on his (V6 engined) rally Sprint so again he may be able to help.
http://www.rallydesign.co.uk/product_in ... ts_id=7202
Using off the shelf components makes life easier if these are suitable so I am thinking it may be worth looking at what the kit car suppliers have to offer?


Uprated mountings make a lot of noise inside the car!!!




Hope this is useful food for thought,


Ian.