Here you go.Vibration-Resistant Serrated Flange Head Cap Screws.

The nuts are Serrated-Flange Hex Locknuts. They are at the bottom of the page.

McMaster-Carr


Serrated-Flange Hex Locknuts

McMaster-Carr

 

A few observations for posterity:
* Because the rivet failed up inside the spring perch hole, I was able to get a caliper in the hole before beginning the repair. The OEM hole appears to be exactly 0.500".
* I did not have access to a pneumatic hammer and had no luck driving the rivet out by hand. What works well is to mark the center of the rivet with a center punch, run a 1/8" drill bit completely through the length of the rivet, and follow up with a 3/8" drill bit run about three-quarters through the length of the rivet. This enables getting a 3/8" drift into the broken (headless) rivet to drive it out of the perch and frame.
* The replacement grade 8 bolt must be at least 1.25" long; a 1" bolt will be too short.
* Fastenal also has 1/2" grade 8 serrated-flange-head bolts and serrated-flange nuts in fine thread. I've put about 500 miles on the truck since effecting the repair and all seems to be holding fine.

 

I have been removing rivets that way for years IMHO the best way to do it.

 

I had this happen some tine back on my old 91. The shop that "repaired" it did a butch job that only lasted a couple months, then it was a lot worse. They used a cold chisel to cut off the rivets damaging the spring hangers. The also used full thread length bolts that didn't do my frame any good. I bought 2 new hangars, probable the last OEM ones in the system and found a heavy equipment shop that had a lot of frame experience. He installed oversized rivets and welded the bracket to the frame. It never moved again. Along with all new bushings, most of my death wobble went away. The last of it went away with a rear brake adjustment.

 

For posterity, I've found a bolt which appears to be a good replacement for frame rivets. (As usual, I cannot claim credit. I was poking around some older threads in this forum and found one in which WannaDiesel made reference to a Huck bolt.)

The bolt shown in the photograph is a "Huck 360" (1/2 inch). (Huck is a subsidiary of Alcoa.) Due to an unorthodox shallow thread design, the bolt is supposedly significantly stronger than a standard Grade 8 hex bolt. Unfortunately, 2" is the shortest length available in the 1/2" diameter bolt. It does contain a short unthreaded shank however, which serves to make the bolt stronger. The bolts do not come with washers so I procured some grade 8 washers at my local farm co-op.

A simple web search for "huck bolt" should turn up some results. I purchased mine from Bay Fastening Systems in Farmingdale, NY. You'll need to purchased both the bolt and the nut due to the nonstandard threads.





Huck Bolt

 

Very interesting...is it an aluminum alloy? It appears to be something other then the standard metal nut and bolt?

I used flange head stover nuts, and flange head bolts for my rivet replacements on my 4wd conversion.

Here are the part number from McMasterCarr...

92316A754 -Grade 8 Steel Flanged Hex Head Cap Screw, 1/2"-20 Thread, 1-1/2" Long, Fully Threaded
90949A037 - Black-phosphate Grade G Steel Flange Locknut, 1/2"-20 Thread Size, 3/4"w, 17/32"h Overall

But recently in my reading and research I came across a reference to a slightly better nut and bolt assembly. Same basic units as above, but with a serrated area on the underside of each flange. The serrations will/should bite into the metal and provided a clamping force that is better at resisting vibrations, and possibly coming loose.

Going through the McMaster Carr site looking for the above nuts and bolts with the serrated flange.

For the nuts it seems that in Gr8 they do not have a 1/2"x20 thread, only 1/2"x13. The Only 12"x20 thread seems to be in stainless.

For the bolts they only carry a 1/2"x13 in Gr5 or stainless, no 1/2"x20

 

I haddn't seen a Huck bolt like that until now but most large truck frames are assembled with Huck bolts.
The tools to install them are way too expensive for one job.

The HuckBolt range

 

Now I know what those fasteners holding things together on my commercial truck are called...always wondered.

I was right...the nut seems to be of a softer, lighter aluminum alloy? Watched a couple vids on the site...quite interesting.

 

Yeah, that bolt/nut dose look to be anodized.
There are close to as many types and materials of Huck bolts as there are regular bolts. We have a small Huck gun 3/8" think.I have never used it though.
I believe there roots are in the aircraft industry.

 

According to the literature I have, the Huck 360 bolt is made of medium carbon alloy steel and the Huck 360 nut is made of low carbon steel. No reason is given for coloring the nut that odd shade of red.

Note that Fastenal has serrated flange bolts (Grade 8) in 1/2" x 20 and serrated flange nuts (Grade 8) in 1/2" x 20. I do not have the part numbers at present, but the Fastenal units are what I was using until I discovered this Huck 360.


It does seem that Huck makes a variety of fasteners, including rivets that require access to one side only ("blind rivets"). Unfortunately, some very expensive equipment is required for the installation. These Huck 360 bolts I purchased are installed with ordinary hand tools -- simply torque to 130 ft-lbs.

 

I have posted this before, so I apologize in advance for subjecting you to the same point of view over & over.

When fastening structural members with a rivet, the rivet actually fills the holes in the members completely, and conforms to any misalignment, etc. This means that you can rely on the rivet to provide mechanical alignment, in addition to clamping force. With a regular bolt, you can only rely on the clamping force, so you have to use a larger fastener than you would with a rivet. There are body bound bolts, which require that you ream the holes in the members in place prior to assembly the fastener, so that the fit is precise enough to provide mechanical alignment . . .

When a bolt used to replace a rivet loosens, it is normally NOT from vibration, etc., but because the members moved under load due to insufficient fastening. . .

 

Understood; but try as I might, I could not locate a shop with the equipment to replace my failed rivet with another rivet.

Note that the rivet failure on my truck was a "cup-and-cone" type -- indicating tensile failure in a ductile material. Therefore I don't think it was a bad idea to get a good Grade 8 bolt in place, which clearly will better resist tensile stresses than the OEM (ductile) rivet.

 

Tap the frame with a tap set. Thread a bolt through the frame and bracket with some locks and you're good. I think the issue is the fact the bolts will move and shift with the environment. The only sure way to make something not move is to weld it.