Rear Diff Pinion Angle adjustment

[PeeBee]

I have adjustable upper control arms under the GQ and needed to roll the diff to get the pinion more in line with the tailshaft, and to correct the mess I generated by destroying the bottoms of a pair of BP51's. The lower control arms are HD after market sets. I have loaded the car up with full tanks of fuel and water to get the suspension sitting where it will approx sit, then started adjusting the arms side to side. I managed to achieve the clearances on the rear diff bump stop mount that destroyed the shockers, and both sides are essentially adjusted to the same dimension 'by eye'. If this sufficient or does the vehicle need to go to an alignment facility to check its 'square'? I have driven it briefly and it drives fine, but I dont want to destroy a set of tires. I think the lower control arms, Un adjustable, should keep the diff aligned - am I correct o is there additional steps to complete?

[BrazilianY60]

I don't think there is anything to be done at an alignment shop for this. If you are happy with the pinion angle, the only thing a slightly different link size between left and right would be one of them forcing the bushes a bit more.

So, to help you not to lose any sleep over this, just take them uppers both out and match their length if anything different.

Cheers.

[PeeBee]

I don't think there is anything to be done at an alignment shop for this. If you are happy with the pinion angle, the only thing a slightly different link size between left and right would be one of them forcing the bushes a bit more.

So, to help you not to lose any sleep over this, just take them uppers both out and match their length if anything different.

Cheers.

Thanks BZ, I have been chewing this over and you are right, the bushes will take any misalignment. I have adjusted using a 6" steel ruler and they are both the same dimension, so will leave it there.

[mudski]

You won't destroy tyres from a bad pinion angle. At worst, you'll go through a uni joint. Maybe control arm bushes. I adjusted mine by eye, with the car unladen, allowing a smidgen for fully load car, and making sure both upper arms had the same eye to eye length. I did this quite some time ago and all the bushes are still like new and the uni's, well, i I changed them out late last year only because i had to replace the end yoke on the gear box end, so two new unis went in.