That looks great, Nay. I'm impressed! (And slightly suprised... 
)
Well, I start cutting tonight. Wish me luck...
)Well, I start cutting tonight. Wish me luck...
Rear Quarter Panel Clearance Cutting - New Technique
- Thread starter Nay
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- Thread starter
- #22
(And slightly suprised...
Well, I start cutting tonight. Wish me luck...
Good luck on the cutting. FWIW, I'm a bit surprised how well it turned out, too - it exceeded my expectations substantially. That's because I didn't do the fabricating
There's nothing like working directly with a good fabricator (as you know
) - we started with the first wrap bends and then you see what it will look like and you go from there. Something you just can't get off the shelf. 
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I would be concerned about the strength of the side support bar mount. The frame is only slightly over 1/8”, (.135”?) thick, if you had welded that tube on before the bumper tube, I bet you could have flexed it by hand, oil caning, flexing the frame side. Not saying that the frame is weak, they are well proven, but look at how Toyota mounts brackets to them. All of their mounts have a large spread and go top to bottom, spreading the load over a large area. Look at the front shock mount bracket, it’s welded around the outside, a hole is cut in the center and welded around and has a tab going to the top of the frame, making for a very solid two plain mount attachment.
If it were mine, I would cut the side support bar ~1/4” away from the frame and then flush with the frame and plate the frame side with maybe 3/16” stock. Drill/cut holes close to the support bar and rosette weld them to the frame, this ties them together reducing flex.
On mine the most often hit spot was the corners, they would bend up and with only one support bar the end near the tire would go down. I would make the plate come all of the way back to the body mount and add a second bar from there to close to the bumper corner.
Pardon my poor photochop skiz, but a plate like this. The gray spots are the support tubes and red holes for rosette welds. For the rear tube that isn’t there yet, you can drill, say a .5” hole and rosette weld it centered where the tube will go, this makes for the strongest setup.
If it were mine, I would cut the side support bar ~1/4” away from the frame and then flush with the frame and plate the frame side with maybe 3/16” stock. Drill/cut holes close to the support bar and rosette weld them to the frame, this ties them together reducing flex.
On mine the most often hit spot was the corners, they would bend up and with only one support bar the end near the tire would go down. I would make the plate come all of the way back to the body mount and add a second bar from there to close to the bumper corner.
Pardon my poor photochop skiz, but a plate like this. The gray spots are the support tubes and red holes for rosette welds. For the rear tube that isn’t there yet, you can drill, say a .5” hole and rosette weld it centered where the tube will go, this makes for the strongest setup.
I completely agree with Tools... Mine is going to be kinda like that, but with some triagulation. (Apparently I wheel mine pretty hard...)
- Thread starter
- #26
Just realized you can't do a single bracket, though, because the body mount is in the way, but there's no question that bracing and/or reinforcing the upward motion of the side wraps is essential.
I think what I'm going to do is build the frame up with a mount to triangulate the brace itself, with the new mount triangulated to the frame. Have to see if all of that will fit, or course....
I think what I'm going to do is build the frame up with a mount to triangulate the brace itself, with the new mount triangulated to the frame. Have to see if all of that will fit, or course....
I'm sure you'll be able to figure something out... BTW, all my cutting is done, now it's time for some extra material and some spot welds. Also, thanks for the heads up on that "Fast Steal" stuff. It's amazing!
- Thread starter
- #28
I wanted to post a follow up to how my design is working so far. After a pretty good rock crawl in the mud and ice last month, I thought I hadn't hit the rear bumper at all. Turns out I had smacked it good on the outer PS corner, just the part that could bend. It didn't
After the discussion here recommending additional bracing, I decided to just leave the side brace welded to the frame - some posts indicated a concern that it would flex, and I agreed with that, but decided that was actually want I wanted.
My reasoning was that with the solid quarter panel "floor" we had created, the bumper could flex upwards about 3/8" before the floor would stop it and then simply spring back, and with the reinforcement it would be extremely difficult to bend the quarter panel as I'd have to buckle the entire thing up into the body. Not sure any bumper would survive that kind of hit.
This seems to be exactly what happened. The brace back to the frame has lost a pencil eraser sized spot of paint, and the Fast Steel "silly putty" took a small hit. The bumper flexed, hit the resistance of the quarter panel floor, and returned to form. So much so I was surprised a month later to see I'd taken a big hit on the underside of that outer edge.
I may still be able to bend this thing, but it is looking like this method of cutting and reinforcing the quarter panels adds major strength to the wings of a rear tube bumper. And Fast Steel rocks
After the discussion here recommending additional bracing, I decided to just leave the side brace welded to the frame - some posts indicated a concern that it would flex, and I agreed with that, but decided that was actually want I wanted.
My reasoning was that with the solid quarter panel "floor" we had created, the bumper could flex upwards about 3/8" before the floor would stop it and then simply spring back, and with the reinforcement it would be extremely difficult to bend the quarter panel as I'd have to buckle the entire thing up into the body. Not sure any bumper would survive that kind of hit.
This seems to be exactly what happened. The brace back to the frame has lost a pencil eraser sized spot of paint, and the Fast Steel "silly putty" took a small hit. The bumper flexed, hit the resistance of the quarter panel floor, and returned to form. So much so I was surprised a month later to see I'd taken a big hit on the underside of that outer edge.
I may still be able to bend this thing, but it is looking like this method of cutting and reinforcing the quarter panels adds major strength to the wings of a rear tube bumper. And Fast Steel rocks
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- Thread starter
- #29
Update on how my bumper and quarters are holding up. At CM08 on Spike, I thought I was down a ledge and wasn't, the net effect was dropping the hammer on the driver's side corner of the rear bumper. This slammed it up into the reinforced quarter panel, which held structurally and prevented the bumper from bending.
I did get some bending of the quarter on the outside right past the last screw of the reinforcement form where it is bolted to the body - lesson learned: make sure you bolt up to the very edges of the form.
I decided to prevent this from happening again, so I cut a hockey puck in half on an angle and grooved it to fit over the bumper brace back to the frame and bolted it up to the quarter panel floor.
This has had two positive effects. One is that the bumper cannot "hit" the quarter anymore, it can only press up into the puck and the reinforced floor provides the structural support so the main hoop will not bend. I have had zero issues since adding the pucks.
The second is that I noticed a bit of an increase in rear end stability, the pucks almost seem to act like small wing body mounts by tying in the frame to the body out at the edges. I wasn't looking for this at all, but it was immediately noticeable.
Here's a pic of the puck on the passenger side. It was taken at a bit of an angle as you can see by the main part of the bumper just for reference.
I did get some bending of the quarter on the outside right past the last screw of the reinforcement form where it is bolted to the body - lesson learned: make sure you bolt up to the very edges of the form.
I decided to prevent this from happening again, so I cut a hockey puck in half on an angle and grooved it to fit over the bumper brace back to the frame and bolted it up to the quarter panel floor.
This has had two positive effects. One is that the bumper cannot "hit" the quarter anymore, it can only press up into the puck and the reinforced floor provides the structural support so the main hoop will not bend. I have had zero issues since adding the pucks.
The second is that I noticed a bit of an increase in rear end stability, the pucks almost seem to act like small wing body mounts by tying in the frame to the body out at the edges. I wasn't looking for this at all, but it was immediately noticeable.
Here's a pic of the puck on the passenger side. It was taken at a bit of an angle as you can see by the main part of the bumper just for reference.
