Nick C wrote:I know someone who has had several of these fail on rally cars, they usually crack and split in the same place yours has folded. His suggested solution was to either run softer bushes to stop the metal having to flex, or to weld a bar through the folded channel, effectively extending it to the end of the arm.
This is exactly what I am thinking.
My previous failures have been cracking, which we believe is caused from the continual flexing of the arm during cornering. The diff stays on the ground (or should) but the body rolls, therefore the arms must flex.
DF wrote:I have hed these fail on my car
The only solution was to weld a plate across the full length and then get it to wrap around the back,
You then have to cut the hole out for the shock to go through but you still have metal left around the shock hole
I didnt take any pickys as i never used to bother
But i hope you know what i mean
These arms are all quite old now so there may be stress fractures that cannot be seen
By the naked eye
Could you not make new ones with tube ( if race regs allow)
Many years ago I tried strenghtening the arms by "boxing" them, ie plating the top face. Unfortunately I just did not like the change in handling that this caused. The arms then failed to flex which meant that during cornering I could not keep the inside rear wheel on the ground. With an open diff it suffered from extreme traction problems. With an LSD it should not be as bad, but I prefer to keep as many wheels on the ground as possible. The other concern is the amount of load at the body attachment bracket, we already have problems with cracking here. If the arms don't flex during cornering the body mount will try and take up the load.
On a rally car on soft surface this might no be as big as problem.
DF wrote:jeroensprint wrote:Hello, read your homologation form.
DF did make the only and best solution and it was done also by special tuning on the rallycars and it is homologated.
Jeroen Rothman
I like photo J
Have you got a better picky of the front suspension strengthening plates ?
Many years ago I had one of these ST front suspension items, from memory it was, a standard mount bracket with a plate welded across the top above the pivot tube.
eightiesflamer wrote:Mark
Do you run the rear anti roll bar
Yes, but is body mounted and attached to the axle tubes, not the suspension arms.
At this point in time my thoughts are to just plate the area around the shock attachmentment area. The object will be to strengthen arm at the weak point, but still allowing it to flex during cornering.
It might have just been a one off failure, but I am not convinced.
Mark
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