Constant Diff Bolt Breakage

[RIP85]

I have an upgraded diff cover and high tensile bolt broke that last week so drilled out the housing and put an even bigger bolt in also broke that last night racing a gsxr600 what have other bf owners done to rectify this problem? I know hi torque do a twin bush setup for 3G and mal wood is working on a new cradle design just hoping for a less expensive fix

Car is a bf f6 manual

[senna_T]

What bushes are fitted?

[RIP85]

Changed from pedders which were a solid bush to super pros with the slots in them so it's a softer type of bush

[The Jizard]

Front 2 and rear 1?

I had issues with superpro comforts in my BF F6, broken bolts, smashed bushes. Not the right type of bush for our cars IMO.

[senna_T]

Changing all three is generally the key - and having them installed correctly.

If you fit the Super Pro comfort series there really shouldn't be an issue sine the diff is basically locked in. Most issues I see are due to only changing the rear centre bush.

I ran them for quite a while in a manual and broke one bolt in 7 years

[RIP85]

I have 10 inch wide rears with a 275 semi slick that's what increased the stress no doubt just destroying bolt after bolt the bushes were replaced less than 150kms ago

[Bonjaz]

wtf are you doing to do all this damage, clutch kicking at 100km??? how much power are you running?

[RIP85]

Nope ease the power on in 2nd it's got 644hp atw on 18psi

[Bellato]

Yea 500rwkw and sticky tyres will probably do that to you lol!

[turbotrana]

Start thinking about redesigning the rear bush setup. It will never do the job regardless of what bolt or bush you use.

I was thinking of putting a bumpstop under the tail of the diff cover. It would entail welding some flats on the cradle and on the tail and having a bumpstop inbetween. If done well then under load the bumpstop will take the load rather than the diff bolt smashing on the bottom side of the bush.

Its one of several ways I have thought to do it but maybe the simplest.