rear spring pin hole question

[ashman]

I've been having problems with my brakes occasionally pulling to the left. All the pads are new, etc so I'm beginning to suspect something is moving around. I checked and tightened all the front spring bolts and I'm in the process of doing the same in the back. As I'm taking it apart, I noticed this:

This is a pic of the underside of the spring perch. You can see in the pic that the spring bolt is in the hole, but it isn't exactly a tight fit. Is this correct? I thought it was supposed to fit tighter than that.

It's hard to tell if there has been any movement but it seems possible...

 

[nvrenuf]

That is wrong! The pin's head should cover the hole completely, like a regular bolt would on a threaded hole. Either it's the wrong size pin or something is bad wrong with the hole in the spring.

 

[dremu]

Maybe the pin wasn't tightened and has "stair-stepped", for lack of a better term. I've seen them do this as a deformation failure mode rather than outright shear. I say C-clamp the spring pack on both ends and pull the pin out.

If thrashed, it can be replaced with an actual spring pin, or in a pinch, a 3/8" fine-thread grade 8 bolt of appropriate length. You can round the hex head down to size by chucking it in a drill and then running the head against a grinder, either bench or angle. (I call it "the poor man's lathe". )

Regardless, tighten to spec as otherwise you'll be doing it again.

Oh, and obviously you'll want to at least inspect both sides, and if replacing one maybe do both proactively.

-- A

 

[ashman]

Thanks guys, thats what I thought. I'll replace both pins asap. Hopefully this solves my problem.

 

[4X4HIGH]

Maybe the pin wasn't tightened and has "stair-stepped", for lack of a better term. I've seen them do this as a deformation failure mode rather than outright shear. I say C-clamp the spring pack on both ends and pull the pin out.

If thrashed, it can be replaced with an actual spring pin, or in a pinch, a 3/8" fine-thread grade 8 bolt of appropriate length. You can round the hex head down to size by chucking it in a drill and then running the head against a grinder, either bench or angle. (I call it "the poor man's lathe". )

Regardless, tighten to spec as otherwise you'll be doing it again.

Oh, and obviously you'll want to at least inspect both sides, and if replacing one maybe do both proactively.

-- A

If you use an allen bolt the head diameter is correct already and they are grade 8 bolts.

 

[ashman]

If you use an allen bolt the head diameter is correct already and they are grade 8 bolts.

Thanks, I I may need to go that route.

 

[ashman]

Finally had a chance to drop the rear axle and this is what I've got.

I bought new spring pins and as you can see the hole is way bigger. Do spring pins come in different sizes?

As you can see in this pic, the hole is still perfectly round (passenger side) just a lot bigger than the spring pin I bought.

This is a pic of the drivers side. This hole is definitely ovalled out. What is the best idea for a fix? New spring perches?

 

[Rtull32]

I believe there is a 3/8" and 5/16"(?) Spring pin

 

[blazinzuk]

I very much doubt that is your problem. I do like a tighter fit, but that little l ooseness should not cause an occasional brake issue.

Got a pic of the old pin?

 

[Hogback Fabrication]

The center pin is only there for alignment and to hold the spring pack together. It's very common for center pins to fit loose in the spring perch, keep in mind that 1/16" over a 40"+ length is a super tiny angle, especially compared to any other tolerance on the truck. That's totally normal (actually better than I usually see) and I wouldn't worry about it at all.

 

[ashman]

Got a pic of the old pin?

The old pins are still in the spring pack for now. They aren't broken and don't really look damaged as far as I can tell. I bought new pins thinking that maybe they were the wrong size or something, but they appear to be the same size.

It sounds like I need to just button it back up and just make sure my u-bolts are good and tight and look elsewhere for my braking issue.

 

[4X4HIGH]

Spring center pins do come with different sized heads. Don't let anyone talk you into using the wrong pin. Measure the hole in the perch and buy the right pins.