Subframe connectors......

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DGrace

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I've been researching subframe connector ideas/designs and have determined the 2"x3" laying "flat" and wrapping the rear frame stub is my best option. I got them cut & notched but noticed the bulge on the driver side trans crossmember where the parking brake cable exits is in the way of the connector landing plate. Thought about splitting the bulge and curling in the sides to make it flat or trying to form the landing plate to match the contour? Haven't seen any pics of anything like this - its a '73 Swinger. Should also mention I'm planning on a ladder bar setup with the crossmember being tied into the connectors. Any input, advice, or experience would be appreciated.

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I used 2x3 1/8 wall square tubeing mocked them up cut slots in my floor welded the tubes to spring relocation boxes slid them from rear to front then welded to trans crossmember no issue with either the fuel line or e-brake , my plan is to tie the roll bar into them .oh I aslo stitched the floor pan to the sub frames also.
 
Biff said:
I used 2x3 1/8 wall square tubeing mocked them up cut slots in my floor welded the tubes to spring relocation boxes slid them from rear to front then welded to trans crossmember no issue with either the fuel line or e-brake , my plan is to tie the roll bar into them .oh I aslo stitched the floor pan to the sub frames also.
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That's what I'm doing but where the driver side connector contacts the trans crossmember, there's a bulge that won't allow the landing plate to sit flat. I am looking for ideas on how to address that.
 
I too , have 2"x3" rectangular tubing sub-frame connectors . My approach " butterfly cut on three sides where it goes onto the crossmember . this gives you more weld surface area . Scribe the connector to the contour of the rear longitudinal . You will need to make a pie cut somewhere in the connector to make it fit . Maybe about 1/4" or so and weld it back together . some floor cutting is necessary but it's minor . I suggest TIG welding everything for maximum strength . Mine can't be seen unless you get down to ground level . Works great , looks great and cost $20 . winner winner chicken dinner
 
383Scampman said:
I too , have 2"x3" rectangular tubing sub-frame connectors . My approach " butterfly cut on three sides where it goes onto the crossmember . this gives you more weld surface area . Scribe the connector to the contour of the rear longitudinal . You will need to make a pie cut somewhere in the connector to make it fit . Maybe about 1/4" or so and weld it back together . some floor cutting is necessary but it's minor . I suggest TIG welding everything for maximum strength . Mine can't be seen unless you get down to ground level . Works great , looks great and cost $20 . winner winner chicken dinner
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I agree but good mig welds will hold up a battle ship.
 
383Scampman said:
I too , have 2"x3" rectangular tubing sub-frame connectors . My approach " butterfly cut on three sides where it goes onto the crossmember . this gives you more weld surface area . Scribe the connector to the contour of the rear longitudinal . You will need to make a pie cut somewhere in the connector to make it fit . Maybe about 1/4" or so and weld it back together . some floor cutting is necessary but it's minor . I suggest TIG welding everything for maximum strength . Mine can't be seen unless you get down to ground level . Works great , looks great and cost $20 . winner winner chicken dinner
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Thanks for replying - are you talking about where the connector ties into the rear frame? I've already got that cut and fit. This is where the left connector hits the trans crossmember. There's a bulge where the parking brake cable exits - the connector landing plate won't sit flat - ideas on how to attach it there. The picture shows the front of the connector where it meets the trans crossmember bulge.
 
how far up are you welding these on the cross member? Can you take a cutting disk and section out the high spot so you get a flat surface AND a positive stop step above to weld to?
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pishta said:
how far up are you welding these on the cross member? Can you take a cutting disk and section out the high spot so you get a flat surface AND a positive stop step above to weld to?
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For the connector to be level, it'll be close to the bottom of the trans crossmember - near where you highlighted. That's one of the options I am considering - split the bulge vertically, fold in the sides and possibly welding the newly formed seam, and the top part of the bulge would form a "step" for the connector to fit under and weld to. My other idea was to angle cut a tube with the same diameter as the bulge and weld up a contoured landing plate to fit over it? As mentioned previously, I'm installing ladder bars & want it to be solid. I've looked but haven't come across anyone who has addressed this. Trying to see what more knowledgeable people have done or would recommend. Thank you for replying!
 
if strength is the ultimate goal, I'd probably section the connector then to conform to the bump. Thats probably easier to do as it can be cut on the bench and wont degrade the strength of the crossmember. trick is to get a nice contour so your not filling gaps with weld.
 
pishta said:
how far up are you welding these on the cross member? Can you take a cutting disk and section out the high spot so you get a flat surface AND a positive stop step above to weld to?
View attachment 1715159377
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On my 73 I went just inside that and lined up directly behind the rail section that goes forward on the front side of the cross member.
I also used 2x3 laying flat and pushed it up against the floor but didn't mod the floor at all.

They do taper slightly together as they go forward, but it made sense to me to tie in directly behind the frame sections that run forward from there.
I also used a piece of angle on the ends of the rails and welded it all the way under the cross member into the end of the section that runs forward from there.
I'm not saying I think you should do exactly the same, but just showing the flat area you could use to solve your problem.

It kind of looks like one big nasty weld, but it's actually two side by side.

It was the first thing I did after I got the car so forgive the crappy looking single exhaust in the pic.:D

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That’s a great idea make a cardboard template , Bob’s your uncle
 
I have a 74 dart sport, but did have the same bulge on the drivers side. I also have a similar subframe connector design.

I just used a BFH and shaped the fishplate to the frame contour and welded it in.

Hard to see the bulge in the pictures, but it's there.
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pishta said:
if strength is the ultimate goal, I'd probably section the connector then to conform to the bump. Thats probably easier to do as it can be cut on the bench and wont degrade the strength of the crossmember. trick is to get a nice contour so your not filling gaps with weld.
Click to expand...
Thank you. I'm pretty sure for my application, either way would be fine but I'd rather have too much than too little. Then there's my OCD that I have to contend with where it has to be level and square, and not to forget my it having to look good.......
 
Think Ill try to fab up a contoured landing plate and see how it fits. I have access to a TIG at work but it may take me a while. I'll post pics - that is, if they turn out decent. Thanks again for all your input. Always nice to have ideas and experience to help along the way.
 
adamm said:
I have a 74 dart sport, but did have the same bulge on the drivers side. I also have a similar subframe connector design.

I just used a BFH and shaped the fishplate to the frame contour and welded it in.

Hard to see the bulge in the pictures, but it's there.
Click to expand...

@adamm What size of rectangular tubing did you use for that? No cutting of the floor required?
 
I used a piece of 1 3/4" pipe and "flattened" it slightly to match the contour of the bulge. Notched the connector to match the pipe and plan on welding the landing plate (2 pieces now) to the pipe.

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I test fit my first design but it was a bit off. I was hoping to keep the pipe within the connector but won't be able to and keep the connector straight. I was able to get a better measurement though for the next try.....

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JoesEdge said:
@adamm What size of rectangular tubing did you use for that? No cutting of the floor required?
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1" x 2", and no cutting of the floor was necessary. I probably could have gone a bit bigger as there is still room before it contacts the floor.
 
adamm said:
1" x 2", and no cutting of the floor was necessary. I probably could have gone a bit bigger as there is still room before it contacts the floor.
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Ditto, but I opted for 1.5" × 3". Went in easy without cutting floor. I snugged it up tight to the floor.

Pat
 
Thanks so much for all of the responses this gives me a great place to start and a few great low cost options to choose from, thanks
 
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