Thrust Angle, Rear axle

[Bill Littlefield]

Since I can't search, I'll post instead.



Took truck in to get aligned and learned the Thrust Angle was out. Thrust angle? That was a new term to me but it means the rear axle is not parallel with the wrong one. In my case, it's aims to the right a bit. If you've seen trucks doing the crab walk as they go down the road, this may be the cause and mine was doing it a little.



Tape measure confirms 1/4 inch different between L side and R side at spring mount.



I took R side apart and pulled it forward with a come-along to take all the play out of it and put it back together. Now both sides measure the same. I'll take it back to Schwab and have them check it on their machine again next week.



Do I have to worry about putting any excess forward pressure on the rear-end or drive line? I assume there is a slip joint in the drive line but did not confirm it.



Bill L.

 

[Randy J]

Shouldn't be any problems with the driveline Bill. Thrust angle problems are very common on vehicles with live rear axles. As long as the front wheels are aligned parallel to the rear (thrust angle alignment), there will be no tire wear, and the vehicle will go down the road straight - albeit dog tracking.

 

[Bill Littlefield]

Thanks

Thanks Randy J.

 

[Deezul1]

In the 60s I used to earn my living doing front end alignment and frame straigtning and we hadnt even heard of thrust alignment for all practical purposes. Mostly get the front wheels paralell and the backs following the front in the same track and all was well. The independent rear suspension vehicles have made the thrust angle important. If your rear tires are wearing even dont worry about the rear alignment, same for the front, if it drives good and the tires are wearing even you dont have a problem.