TJ A-pillar to frame tie in help

RHSCTJ

RHSCTJ

Well-Known Member
Joined
Jul 1, 2008
Location
ROCK HILL, SC
I'm just about ready to start bending tube for my tj but I'm having a hard time finding useful info on tying the A-pillar to the frame. I really don't want to just go through the tub but with all the structural channels I don't see a good way to bolt the cage to the tub without getting way over towards the pedals. Anyone have any advise?
 
Mine was a flat dash conversion of sorts so it was easier for me. Theres a spot under the dash on the floor up against the outside walls of the tub that you can foot plate and duplicate underneath. You have to cut a access hole into the corner of the tub/firewall from the other side. From the bottom plate you can then bend a piece to connect to the frame. No easy task however.
 
XJsavage said:
Mine was a flat dash conversion of sorts so it was easier for me. Theres a spot under the dash on the floor up against the outside walls of the tub that you can foot plate and duplicate underneath. You have to cut a access hole into the corner of the tub/firewall from the other side. From the bottom plate you can then bend a piece to connect to the frame. No easy task however.
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Got any pics? Ive got the tub up on it's side now and I just don't see it.
 
The guy that did mine got it 90% of the way there, but screwed up the last 10%. The trick was to start at the drain hole in the corner of the footwell and open that up to make room for a baseplate that sits on the (thicker, I believe) piece of metal down below. Then make a little adapter piece that goes on the underside from the baseplate sammich back over to the frame.

If you're careful about it, you can notch the corners of the dash board and sneak right down where you need to be.

And please don't die your door header bars into little flat plates that bolt to the windshield. :rolleyes:
 
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^^ OK groovy, third pic down under the clutch pedal where the floor goes from flat to angled up is where mine was.
 
@shawn what's the deal with the main tube in the third pic? Why the little kick off piece?
 
Did you see where I said he screwed up the last 10%? That's literally the last 10% of the tube, but it's also the last 10% of the project: making sure the details get addressed.
 
Mine is basically like Shawn's except that last 10% ;)

Mine is boxed into the frame in about the same spot. I have read some mixed reviews of the flat plate that goes beside the dash, so I wanted to go through the dash with DOM.
 
I can see some "basic science of metals" coming into play here. :flipoff2:
 
shawn said:
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I really don't like that, that's a weak spot that needs to be addressed. You're feeding the loads down that tube into another (bent) tube that is basically already pre-buckled, and into a tube weld that's loaded in shear. If you don't need to rely on the cage, it doesn't matter. If you do, it does. You'd be better off cutting out that jog in the tube, and adding an "S" to connect the tube to the floor plate.

There's actually a few things I don't really care for. You've tied the body to the frame with an outrigger of sorts, so the body isn't really free to move anymore and you might as well use rigid body mounts. That's really all that outrigger thing is actually doing, because the outrigger thing is butt welded to the frame at a right angle with no triangulation, and most all of the loads on the cage are going to put the outrigger thing in bending. So really all the roll cage loads are going into the floor pan through the bolt plate, just like any off-the-shelf bolt-in cage, and the outrigger thing might add some body stiffness but will add very little actual strength to the cage.

It wouldn't be bad to add a larger piece of thinner plate to spread the loads around the floor area too. I've seen foot plates like that rip right through the body, but that's been on race cars with more rollover energy than you're likely to see..

So if you roll, do it slowly and gently. Don't roll down any hills or backwards off of anything steep.
 
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If y'all want to tell David about all the bad decisions he's made, you can go find him on Facebook or Pirate or wherever he hangs out nowadays. :shaking:
 
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