I have a 1992 F150 4x4, it was starting to pull right, I took it in for an alignment and they noticed I was dog tracking. I took my truck back home and found the pin/rivet that goes thru the middle of the leaf springs on the drivers side had failed and the rear axle was working its way backwards. I replaced the rivet with a grade 8 bolt and am putting things back together.

My question is does anyone know how closely aligned the axle housing needs to be? I measured from the front spring shackle to the spring pad on the axle. I am 1/4" off from side to side, is that close enough?

Thanks,
Greg

 

Nope.
That 1/4 in. will cause your rear tires to cup and wear unevenly.
You may want to look into replacing that spring pack.

 

Are you saying the center pin of your leaf pack failed? There should be no load on that pin if your u-bolts are properly torqued. Replace the pin (sounds like you did), install new u-bolts only, properly torqued, and checked several times after initial installation.

If you're off 1/4" I'm guessing your spring eye bushings are shot. Removing the rubber ones sucks, easiest to replace with poly. Otherwise there's no alignment you can really do; your main leaf dictates axle placement and it can't stretch from the front spring eye to the center hole. Your spring hangers might be rusting thru if you're in the rust belt but otherwise they're riveted to the frame and they can't move.

And I vote that 1/4" side to side is fine unless you're going to be flying around a race track at 150mph. I bet most of these trucks are off that much in multiple important areas, simply no one knows because no one puts a tape to them.

 

D60, thanks for your reply.

You are correct, the center pin in the leaf spring pack rusted completely off on the drivers side, it was down to less than 1/4" in dia on the passenger side.

You are correct that the U-bolts had worked loose, which is what got my attention while driving. One day it drove straight the next dog tracking really badly! Not sure how that happened, it hasn't been touched since 2006, but I will keep a close eye on it now.

After putting it back together I took the truck to an alignment shop. The rack shows the rear thrust angle is off, but was within allowable limits.