Trailing arm bolts and washers

[Tom Sarno]

I installed my trailing arms with a new bolt kit from an aftermarket source. The hole for the cotter pin was past the top of the nut and would have been ineffective. The assemble manual shows a lock washer that was not in the kit I bought. The washer would have to be 1/8 thick for the pin to be in the castle nut correctly. Is the lock washer this thick or is it possible that someone cranked down the nuts without enough shims causing the frame to pull in? The manual shows what looks like a toothed lock washer and they are usually on the thin side.

Thanks
Tom S

[Joe L.]

Re: Trailing arm bolts and washers

Tom------

It's VERY possible that someone has previously distorted the frame box section where the trailing arm mounts. This is caused by torquing down the bolt without a TIGHT shim pack. The last shim installed in the shim pack needs to be driven in with a hammer. To do this, after determining the shim pack needed, remove the one of the thickest shims. Then drive this shim in with a hammer. You MAY be able to correct the distortion in this manner, but you'll need to figure on a shim pack which is thicker by the amount of deflection than what's required now. Using an inside micrometer, measure the width of the frame cavity near the top or bottom (where any distortion is no likely to have occurred). Then, measure it near the bolt hole. The difference is what you need to add to the shim pack over-and-above the total shim pack necessary to get a TIGHT shim pack now.

Another possible problem is the fastners that you're using and the way that you're assembling them. The bolt head (which obviously goes on the inside) should have a flat washer under it. The outer side should have a flat washer, an external tooth star washer, then the castle nut. There are different types of castle nuts. The correct one for this application is the type with no shoulder.

Once you are sure that any frame distortion has been corrected, if necessary, and that you have the correct fastners correctly installed, you can vary the thickness of the outer flat washer to obtain proper cotter pin engagement of the castle nut.

[Gene M.]

Re: Trailing arm bolts and washers

Be sure the bolt is the correct length and not the longer bolt that is used on the rear end forward cushion bracket.