R31 Tailshaft Vibration

[The_Modern_Greaser]

Hey guys,

i've recently lowered my R31 and since I've been getting a bit of vibration from the tailshaft, I've worked out by lowering it i've straightened the tailshaft out and they're meant to have between 1 & 3 degree angle.

I've tried spacing the transmission crossmember out with washers, first 3, then down to two, now i'm dawn to one washer on each bolt, but its still vibrating.

i've heard its a common problem but can't find a solution. I was wondering if anyone knowshow to fix it.

CHEERS

[Daleo]

Have you checked the centre bearing? When they wear, you will get a pretty good vibration. What about the condition of the uni's? Are they greasable?

By putting washers under the gearbox mount, you are misaligning the wrong section of the shaft, you'd be better shimming the centre bearing to reduce the included angle of the shaft, rather than increasing the misalignment.

Also, it might be worth looking at an adjustable panhard rod to centre the diff, as lowering pushes the diff sideways. This is another source of misalignment.

What is the condition of your rear upper control arm bushes? And lower arm bushes for that matter. The upper arm bushes are a common wear item and could be causing the pinion angle to be larger (nose of diff pointing down) increasing rear uni angle.

Good luck.

Edited January 1, 2012 by Daleo

[sweefu]

^ This is good information. Depending on the universal joints installed in your tailshaft, they may be greasable. The stock items I removed from my tailshaft were not, though the aftermarket items i installed were.

[R31 POWER]

Get some 50mm x 50mm 4/5mm flat bar x2, drill hole in middle and put between the center bearing bracket and floor. That should fix it. Even test with washers to see first if you don't have flat bar.

[nobby]

Yep all the rotating parts have worn-in one way and changing the angles has upset it.

It can look ok but angles don't need to change much.

Or for that matter even new parts may wear quicker in the altered setup.

I agree with the boys miss-alignment causing vib.

[erik]

and get an adjustable panhard rod

[Daleo]

and get an adjustable panhard rod

Have you checked the centre bearing? When they wear, you will get a pretty good vibration. What about the condition of the uni's? Are they greasable?

By putting washers under the gearbox mount, you are misaligning the wrong section of the shaft, you'd be better shimming the centre bearing to reduce the included angle of the shaft, rather than increasing the misalignment.

Also, it might be worth looking at an adjustable panhard rod to centre the diff, as lowering pushes the diff sideways. This is another source of misalignment.

What is the condition of your rear upper control arm bushes? And lower arm bushes for that matter. The upper arm bushes are a common wear item and could be causing the pinion angle to be larger (nose of diff pointing down) increasing rear uni angle.

Good luck.