Spring Replacement

RCMAN46 wrote:

I would recommend using a plumb bob and make a mark on the floor below the king pin. Then do the same at all 6 spring hangers. Then measure to each hanger mark from the king pin mark. Each side should be within 1/4 inch. Then measure distance between the hangers on each side. If they differ by more than 1/8 inch you may want to consider moving a hanger and if you are lucky only one will need to be moved. If they do not measure correct and you leave it as is you will know why the tires do not wear even and frequent rotation may extend the tire life.
I assume you have a Lippert frame. Lippert is famous for not getting the hangers correct.

This is actually good advice. But why not also measure your axle center too at the same time. Drop a plumb from the center of each of the wheels and mark them. Then measure that from your king pin center. If the measurements are with in an 1/8", you are good. What is important is where your wheels are. Not where the hangars are. So you MUST be able to adjust your axles perpendicularity, or parallelism to the other axle. But really the shackles attach to the spring and also the hanger. If the hanger is off location by a 1/4 inch the ANGLE of the shackle changes slightly to makes up the difference. But that does not move the wheel location. I don't regard hanger position as all that critical. But the wheel location is what is really critical.

Since it appears the OP did not mark the wheel or original axle alignment, RCMAN's plumb/marking technique is a pretty good home method of making sure the wheel alignment can be restored to being close to where it needs to be. And maybe close enough.

Just as a reference...my rear axles were 3/8" out of parallel with the front. Broke the spring and had it replaced in Statesville, NC. Repair house never aligned the axles. The rear tires wore out in 1500 miles. One on the inside. The other wore the outside. Rear tires were junk when I got to central NH. Just 3 days later.