I know the rear most body to frame bolts on the 3w’s are spring loaded to help prevent the body cracks along the tail panel to quarter seam. I’m guessing I don’t need spring bolts since I bobbed the frame and have a roll cage to prevent frame flex that causes the body cracks. what do you builders think?
Didn't know about the springing so I guess I've learned something today. There's quite some clearance between the body and frame at those rear bolts which needs to be shimmed. Can't imagine the carnage that could ensue if they were seriously tightened without shims especially if the other body bolts were already in. No plate at the foot of the cage? I don't know whether there should be or not. Chris
I have zero gap at the rear most body mount bolts I think the 10ga subframe extension it’s going to be welded to and the rear triangle brace is enough for the cage mount.
That’s not how Henry designed his, so you are charting your own course. I own a virgin Tudor that has never had the body off the frame. There are no springs on those rear bolts, but there is a thicker shim between floor and frame.
Take into account that original Fords were meant to flex a lot more than we like to see nowadays. If you are boxing the frame, and building a cage inside the body, you will be ten times more firm than original.
I didn’t reshape the frame and subframe. But they bolted together with no gap. my frame is cut off at the last body bolt. This is a 3 window if that makes a difference.
Maybe 3-windows are different. Or maybe your new parts are different. Did you set them up on the same jigs Ford used?
Looks very much to me like it's a fabricated frame, so all bets are off as regards why it has no gap. I can imagine how someone could get confused over the springs, as there was a spring on one side of the tank. Chris
That cage doesn’t look like it’s attached to the chassis, so it’s not doing anything to stop the chassis flexing.
Okay okay. the frame I built to exact specifications. The frame follows the subframe perfectly as it should. I’m still in mockup stage and didn’t put the rubber between the body and frame yet. The cage is still being built and I only have one tack holding it in. And yes, there is a spring loaded rear most body to frame bolt. When reinforcements were added were the quarters attached to the lower back panel to prevent stress cracks. The length and type of the rear most body to frame bolts was changed at the same time with the addition of the spring to help relieve stress
Learned something new today. Never seen anything about using a spring on the rear body mount. I wonder if that is still needed with a new fully boxed frame under a Brookville body coupe. The bulletin listed by OP states that this is for cars driven on the rough roads of the day. Is there a danger of cracks appearing since we all get to drive on paved roads.
I see too many newly build 32 coupes with cracks in this area. I just had to ask why so many crack in this area. Two out of three 32 fords I just saw at a car show we’re cracked or starting to crack
A few things I'd look at, 1- did you box the frame? 2- do you plan on, at any point mounting any part of the roll cage to the frame itself? If you did box the frame and you plan on mounting the roll bar to the frame itself I'd bolt the body solid to the frame. If you boxed the frame AND the roll bar will ONLY mount to the body, I'd use a hard rubber 1/4" pad between the body and frame (think hard rubber like that has the reinforcements sandwiched in it). If you didn't box the frame and mounted a roll bar I'd expect to see some cracking in body panels as something will have to flex and since the frame is much thicker than the body, the body will do the cracking/tearing first. Now I'm assuming at least a 6-point roll bar setup, if it a 4-point I imagine cracking outside of where the 4 points mount. As in your creating a solid center area with flexing on both ends of the car. Without seeing it in person it's all guess work though.... ..
I just finished putting an original 32 roadster body (no mods, no metal work of any kind) back on its original frame (same deal - all stock). There was about a 3/8" pad between the frame and body in the area you're showing. We made new pads out of semi-hard rubber and inserted them in these locations. We also made about an 1/8" rubber pad and inserted in the next body bolt going forward - as it too had a gap - though smaller. This was important to get the doors to close correctly (body flex in the middle). There were no spring bolts in the rear when this roadster was originally put together (we were the first to take the body off the frame).
I'm not sure if I'm identifying the crack correctly or not. What seems to me is that the location of the crack would be caused more by stress from not mounting the body correctly and placing stress across the back.....rather than the frame flexing. I say that because its behind the last attachment point. Also is this occurring on both fiberglass and steel bodies.........and on coupes as well as roadsters. Not doubting that it happens, but wondering if frame flex is the cause. Most(?) people today box their frame rails, but some of the crossmembers I've seen don't appear to be all that substantial, often being built of thin tubing, and I always wondered if they were done that way for ease of component installation rather than a strong chassis.
The body crack is from the rear portion of the frame bending down from the weight of the gas tank and bumper. And sometimes people sitting on the bumper or towing. The spring allows the frame to flew down without pulling on the tail of the body. I shouldn’t have this cracking issue since my frame is cut off at the last body bolt.
^^^^ there is also book 2 , 2 book vol set , The gap @ rear sub rail is adjustment like the front cowl foot /leg, after doors / body adjusted I make a shim to take up the gap ,,, How is the cage / roll bar installed ? Look to be just to subrail , By looks of rear your not going for much Hp or Toque, For stiffen the frame you could make mounts with slip tub & cross bolt @ all mounting point also removable to remove body , Late 80s early 90s NHRA made a big fuss about bolt in & sleeved Roll cage /Bar , there was a 39-41 Black Ford sedan & Orang 40 somthing, Sedan with Blown Injected BBC ( Fat Attack cars? ) took a bad tumble around 1/4 , That ran I believe low 8s 1/4 , then Roll Cage did it job , & I believe National Dragster did a write up in Tech article The Sedan has been posted here on HAMB in last few years being fixed restored, ( featured in many magazines)
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