Question : Rear subframe Bushes

[Agon]

After changing my rear subframe bushes about a month ago(with stock lemforder ones)  i noticed today that  the right side bush has developed some cracks in the rubber as there were in the old bush , can anyone help me why this happened ?

[reesky]

Hang on - by rear subframe do you mean rear beam?

 

If so - the whole design of this rear beam is terrible, the bushes pivot and squash at a hideous angle. Not sure it makes a huge different but did you tighten the bolts with the car in the on the ground position? I think that's how it should be done.

 

I'll be swapping mine for Lemforders soon too!

Edited 22 October, 2017 by reesky

[Agon]

yes rear beam then , it was tighten while it was jacked up , not on the ground so maybe that added more pressure on them or something :/ hopefully is only the right side one , i will change it again as its still lubricated because it was a PIA to get out...

[KenONeill]

@Agon - I'd agree with @reesky about the cause of your problem; by tightening those bolts without weight on wheels you've introduced a pre-load to the bushes so they're pretty much always at limiting load with the car at normal ride height.

[Agon]

If i jack the car up ,untight the bolts then put the car in its own weight and tighten them again will that do the job ?  Sorry for my bad english.

[octyal]

24 minutes ago, Agon said:

If i jack the car up ,untight the bolts then put the car in its own weight and tighten them again will that do the job ?  Sorry for my bad english.

 

Yes, I was going to suggest that. Raise it up, slacken bolts, then re torque when full weight is on the ground. Same applies to any suspension bush, even lower shock bolts on the rear, front arms etc. By tightening without any load on them, as said, it introduces the wrong preload, leading to premature wear.

[KenONeill]

3 hours ago, Agon said:

If i jack the car up ,untight the bolts then put the car in its own weight and tighten them again will that do the job ?  Sorry for my bad english.

Well, that will correct the pre-load, but if I'm reading post #1 correctly you've already got stress cracks in one of the new bushes.