Howdy Hamb! I want to make some bolt in upper rear shock mounts for my hotrod 54 pickup. I’m always amazed that the super common racecar type tubing with ears crossmember is strong enough- they look flimsy to me but I’m no race car fabricator. Since this is a street build I tend to over build stuff instead of going for maximum light weight. My ears are welded to the axle already and I have it mocked up with some fancy shocks I bought. The measuring phase is all done. I ordered some bolt in shock pins/studs and my plan is to make an L that bolts to the bottom frame rail, then comes up inside the frame with a 3/16” plate that will hold the pin. I’m thinking either all 3/16” plate or maybe a 1”x 1/8”wall square tube with all the mount ears welded to it. Should I be looking at doing more than just one small gusset on the 90° if I use plate? Do I need three bolts or would two do the trick if it’s wide enough to resist fore/aft rocking? 5/16” bolts seem like the ideal compromise between strength and not weakening the frame unnecessarily with big holes? Anyway, I have the shocks and the lower mounts, just gotta fab up the brackets to hold the upper studs when they come in the mail next week. Thanks for any thoughts! Radar
that won't work for long. How about a vertical channel, with the bolt in the center web of the channel? then it will have some bending resistance.
I think what the squirrel is saying is you have all the load.on the very bottom of the frame rail, so the mount itself will just flex the lower rail flange. That mount will work as if the "C" frame rail is nothing more than a flat piece of iron because you have no other support from bracket going to any other part of rail. At least that's what I'm seeing with your design, especially with the length of your mount and the leverage it will have against that lowly little bottom frame flange..
It will probably snap or bend at the stud mount, or could bend at the bottom of frame i see it bending the frame myself.
I was thinking it will likely break just below the stud mount. The rest of it seems to be pretty well reinforced. If you changed that gusset that is in the center of the lower half of the vertical flat piece, to two gussets (one on either side) and have them extend up all the way, it should be ok. the overall design looks kind of complicated...I'd do some more sketching of different ideas for a while before building.
The flange the shock stud is on will fail; that's almost identical to what the PO did on my car and both broke... I'd do a 'C' mount, attaching to both the top and bottom rails of the frame, and I'd use 1/4" plate for the stud mount.
If they are on the frame, what’s wrong with the stock ones? Even if you had to move them These are on my ‘57. Pretty sure they are the same
Nothing is stock back there and I do need to move them up to correct the angle from lowering. Sadly the originals were rotten and are long gone. I do have a pieces of frame rail from Z cut sectioning the frame that will be useful for use as a fixture so I can tig up the bracket on the bench.
A piece of channel that spans the width of the frame would probably work. Drill holes and mount the shocks inside of it, using spacers as needed.
Maybe a 1/4" mount plate and a 1/2" arm to bolt the shock to. Similar to these I made for another car; but suited to your application.
usually takes me about ten different ideas to come up with one that I like. Keep going, you're getting closer!
Seems like pulling the bed and off topic ignition etc. for welding in a new crossmember is the best idea. It’s just so dang hot out in the driveway I’d love to not go thru all that! Thanks and anybody else that has pics I’d love to see em- I’m still not done wanting to bolt them up
If you decide on Speedway's upper shock mounts, be sure to grind and reweld the puny tig welds. Yeah, they're pretty but they have absolutely zero penetration. When mine broke, I rewelded the welds with my mig welder and attached them with 5/16ths bolts and welded them solid to my frame rails after boxing the rails..
How far away from the "C" channel frame will the stud have to be? Can you turn the shock 90 degrees and have the shock mounting hole running the same direction as the frame rail? Then you could just add a bracket attached to both the top and bottom flange of the frame, and have the shock mounting bolt go through the bracket so the shock is mounted between the two flanges of the bracket and the shock bolt is in double sheer. Gene
Ok so I decided sometimes being lazy is more work that keeping it simple and doing it right. I ordered a weld up kit from comp engineering with a tube and ears meant to hold up over a coilover setup. I’m going to pull the bed, weld 3/16” boxing plates on the frame which are drilled so the tube is a snug fit passing through, then weld it all solid. That way the weld on the tube will just be keeping it from twisting and not need strength in shear (probably overkill but it will also guarantee alignment).
Boxing is the way to go. with hollow spacers inside from inner wall to inner wall. Then run bolts thru the boxed frame and the inner hollow spacers.
Well if I’m going to bother to pull the bed off to weld in boxing plates I’m not going to bother making cold connections for the shock mount- the bar and ears are getting burnt in for good. For a bolt in situation though I agree it’s no good putting a clamping force that can just crush the box tube- you gotta have sleeves welded in there.
How I'd do it, take a piece of 1/4" plate 5" long, bend into "C" to fit over the top and bottom of your rail, drill hole in middle for your shock mount and drill a couple holes on the top flange, a couple on the bottom flange and bolt together or if you don't care weld it on. You create a small box that will do everything you want it to do with no problem and have double flanges to stop any flex.....
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