vibration accelerating after lift kit

[aggiedave98]

I just finished my fabtech 3" lift kit on my '89 suburban 1/2ton 2wd. On the rear I have 2" lifted leaf springs (although it lifted it more than 2" compared to the old springs).

When I accelerate from a standstill, I feel a vibration it seems like from the wheels. It's almost like the wheels are hopping on the pavement. Could this be the drive shaft vibrating because the angle of the 2nd half of the drive shaft between the crossmember and the differential is too sharp??

Thanks!!

[68LSS1]

Yes, it's because your pinion angle is now off. Imagine holding a plate out in front of you. Turn it and imagine that it is the rear u joint. Tow tilt the top of the plate away from you and turn it. Now your plate (or u joint) is traveling in a oval instead of a circle. At the top and bottom of the oval is where the "wheel hop" is coming from. You can get tapered shims to install between the leaf springs to correct this. Or custom make the carrier bearing mount (lower it).

[aggiedave98]

Thanks!!

Is the problem the angle at the carrier bearing? Because the angle at the rear U-joint tot he differential is pretty straight.

Where can I get tapered shims??

Thanks again so much for the help.


In the short term, will it hurt it to drive it before fixing it?

[LONGHAIR]

Lowering the carrier bearing mount should fix it. It will not take much, an inch or so.

Do NOT drive it until it is fixed. You will end up with a far worse problem if you do.

[aggiedave98]

how can I lower that carrier bearing?? the support for it mounts above the crossmember, so I'm not sure how I'm going to do that...

thanks for all the help!!

[68LSS1]

Originally I was going to design a a aluminum bracket for my local machine shop to fabricate. (Not necessary for me now as I have a short bed truck and will be using a one peice.) I think the previous owner on my truck just rigged it in with a peice of angle iron.