"Best Way" Spring Hanger Mounting?

[7dee2]

Not sure if this has been covered before but we need to hang our D60 & 14 Bolt DRW axles on my Longhorn 4x conversion project and could use some advice on the best way to do this. We’re replacing all the spring hangers and punching all new holes as none currently line up.

Originally we planned to weld up any holes that partially lined up and then re-drill and bolt them on with 3/8” grade 8 frame bolts. Found that most all the hangers original rivet holes have a little larger opening than that, new plan is to punch everything over to 7/16”.

A friend suggested we just weld um on and forget about it? My question being is welding any of this a good idea or would some flanged frame bolts with self-locking steel flange nuts & Loctite Red be enough? Seems like some hanger to frame weld might help them from egging out the frame holes or is this overkill?

[kwmech]

Using the frame holes as a template I would drill out the bracket than the frame rail. The factory holes are on the edge of 10mm in size. I've always gone to 7/16 fine thread gr. 8 with grade 8 flats and a locking nut such as either a pinch or flange lock, then torqued them down to 70 lbs. I even did an experiment one time with just a regular nut torqued to 70. After 20 years it never came loose

[7dee2]

Modifying the bracket rather than the frame when possible makes good sense.

Was the regular nut used with a lock washer or anything else like a threadlocker?

[junksaver]

You may not be able to redrill the upper holes in your bracket to match the frame. It appears the upper holes in the frame are to high for the bracket. It looks like the bracket is not flat where the upper holes in the frame are.

The nuts you want to use are lock nuts. They do not require a lock washer or thread locker and will not back off on their own.

[kwmech]

Originally Posted by 7dee2

Was the regular nut used with a lock washer or anything else like a threadlocker?

No it wasn't, just a flat washer and my snap-on torque wrench set at 70. These were holding in a dropped front x-member that I fabricated to convert a 2wd frame to 4x. Somebody now owns the truck up in Washington state

[7dee2]

Originally Posted by junksaver

You may not be able to redrill the upper holes in your bracket to match the frame. It appears the upper holes in the frame are to high for the bracket. It looks like the bracket is not flat where the upper holes in the frame are.

The nuts you want to use are lock nuts. They do not require a lock washer or thread locker and will not back off on their own.

You are correct on the fitment of that bracket right now. The right side fits a little better than this one on the left. Going to work this bracket a little and see if we can get it to fit a little better before making any mods.

Originally Posted by kwmech

No it wasn't, just a flat washer and my snap-on torque wrench set at 70. These were holding in a dropped front x-member that I fabricated to convert a 2wd frame to 4x. Somebody now owns the truck up in Washington state

Wow, you would have thought that would have backed off by now if it was going to. I'd think the fine thread helps it to stay put also.

[JJorgensen52]

Originally Posted by 7dee2

You are correct on the fitment of that bracket right now. The right side fits a little better than this one on the left. Going to work this bracket a little and see if we can get it to fit a little better before making any mods.

When I went through mine, I was able to get one of the holes to line up on each side close enough that when I punched them over (7/16") it came out in the wash. I welded up all the other holes, bolted the bracket on with the one that lined up, and then punched the new frame holes in the same operation as enlarging the bracket holes.

I used all flange-headed gr.8 bolts with self locking (Keps is the name) nuts. GM actually specs those in the service literature for rivet replacement (I have a reference somewhere), and you'll find them used in the square body frames where cross members and things are bolted in.

[7dee2]

Here's a link for others to JJorgensen52's build where he mentions the hardware with some pics. Scroll down to pic 2 & 3. http://67-72chevytrucks.com/vboard/s...1&postcount=70

We are looking to duplicate the same hardware you used Jim. Are those bolts 7/16-14X? & 5/16-18X? and would you use the same thread pitch & length again, or? And BTW The "Red Herring" gauges look amazing!

[JJorgensen52]

Originally Posted by 7dee2

Here's a link for others to JJorgensen52's build where he mentions the hardware with some pics. Scroll down to pic 2 & 3. http://67-72chevytrucks.com/vboard/s...1&postcount=70

We are looking to duplicate the same hardware you used Jim. Are those bolts 7/16-14X? & 5/16-18X? and would you use the same thread pitch & length again, or? And BTW The "Red Herring" gauges look amazing!

Thanks! They turned out awesome.

Back on subject Yes, I would definitely use the same pitch again. They were 7/16"-14x1.5" and the other 3/8"-16x1" (I also used a few 3/8"-16x1.75"). If I were to do it again, I would probably try and get some shorter bolts, some of them were a tad on the long-ish side as you can see in my photos. I ordered them that way because they were cheaper in bulk (I ordered from McMaster-Carr).

I will tell you one thing though. Those suckers are NEVER coming apart. I actually used an impact wrench to assemble the frame because they're that tight to bolt together.

[7dee2]

Excellent, thank you Jim appreciate the info! Wasn't sure on the smaller bolt from the pic the 7/16 dwarfs that 3/8.

I think the bolt hardware is nailed so anybody have any thoughts about adding weld anywhere other than to fill partial frame holes? Or would that kind of thinking be a little more secondary if things are going south due to whatever reason? Point being "extra insurance" or "overkill" as it relates to spring hangers?

This is a little off topic because this is a cross member example. This truck is a 72 Longhorn 4x conversion that has been for sale on eBay. Pretty sure all the rear hangers (original) are factory riveted and not sure if the fronts are bolted only? Some heavy sway bars were added perhaps due to a humongous camper. You can see the square body front cross member that was added is bolted and welded. Can't tell for sure from the pic but the angle iron added to the rear frame rails may have been welded on the end also?

Seems to me that was a smart decision to weld the front cross member or perhaps it became a necessity?

[JJorgensen52]

From an engineering standpoint, if the cross member is properly welded in, you should have no issues. But you need to be careful of undercutting or introducing too much heat and changing the metallurgic properties of the frame around the weld.

Back when I was researching this myself, I found a thread (which of course I can't find now ) about bolts vs. welding, and as I recall the consensus was that our frame rails are too flexible (unless you box them) to weld the cross members in, that it will just lead to cracking of either the welds or the frame near the welds.

I would be inclined to believe that, both based on the amount of flex I've seen in the trucks, and because when GM started welding frames together was when they started using hydroformed box rails and heat treating things.

Food for thought.

[7dee2]

Answers my question and the weld thinking will remain secondary. Jim this might have been part of what you read in your research.

Here's a partial quote from the Frame section on Frame Repair in the 1972 Chevrolet 10-30 Series Truck Service Manual:

Welding
NOTE: Do not weld into corners of frame or along edges of side rail flanges. Welding at these points will tend to weaken the frame and encourage new cracks.

Bolting
Wherever rivets or failed bolts are replaced, bolt hole must be as near the O.D. of the bolt as possible to prevent bolt from working and wearing. Drill out and line ream hole (or holes) to the bolt O.D.

[JJorgensen52]

Originally Posted by 7dee2

NOTE: Do not weld into corners of frame or along edges of side rail flanges. Welding at these points will tend to weaken the frame and encourage new cracks.

This makes perfect sense, due to stress concentrations at those points. Not sure we need to get into that discussion here though