Checking axle alignment

As long as both axles are parallel it doesn't matter about the distance to the king pin. If it is off a little all it will do is make the trailer follow a little to one side. Not enough to matter. It is not uncommon to see big rigs tracking sideways.

N-Trouble wrote:
I was wanting to check the alignment of the axles on my trailer and was thinking of tying a weight to a string and hanging it from the kingpin then marking that spot on the ground. From there measure back to some point of the axle/wheel on each side and comparing. I realize this is a crude method compared to using a laser setup that I suspect most alignment shops probably use but would it at least tell me if I have any kind of alignment issue?

I did a similiar measurement. I used the floor in my shop building I store the trailer in.

First a plumb bob from the king pin to the floor.

Then a plumb bob from the front shakle of each axle both sides.

The distance from each shakle of same axle to the king pin should be the same.

Then check distance between shackles on each side they should be the same.

Then width distance between shackles.

Check that all springs are same length and same number of leaves.

Plumb bob from axle tube. The distance from axle tube to front shackle should be the same for all four. If one is off then there may be a center bolt problem with a spring.



Had a friend where the shackles on one side of the trailer were about one inch forward compared to the other side. Required a trip to a welding shop to locate the hangers where they should have been.

Basically that's it. I see your 5er is new, but for older units, be sure to check the shackle bushings and suspension first.

This is a great post by member JBarca on replacing his axle and fabricating adjustable mounts so he could align the axles.

I used this Correct Track II bolt on alignment system, but the one that JBarca made as described in his post is more exact.

Essentially when you measure from the kingpin to both sides of the front axle, the measurements should be within 1/4", and same tolerance when measuring between the axle centers on both sides.