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Frame swap question #2821543
09/16/20 01:41 PM
09/16/20 01:41 PM
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JWK57D100 Offline OP
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I have decided for sure to swap the body on my 57 D100 to a dakota. I went back and forth about doing the front clip or the whole frame but decided to go with the complete swap. I think this will make it easier in the long run keeping the drive train lined up and not having to make more mods outside or the body mounts and transmission tunnel. The thing I need help with is year choice for the donor truck, I have found an 88 and 98 for close to the same price and I know with the mid 90's model it has the 6 lug and I would loose a good deal of bed space. Is this going to be the same on each year or would the older frame have less rise in the rear of the frame. Thanks in advance guys.

Jeremy


1957 D100
Re: Frame swap question [Re: JWK57D100] #2821611
09/16/20 04:10 PM
09/16/20 04:10 PM
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British Columbia, Canada
Old Ray Offline
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The resident expert and guru on frame swaps will be along shortly, but if the wheel bolt pattern is a concern they can be changed to a five bolt, as I have done on a '92.
Would fuel injection or carb be required?

Re: Frame swap question [Re: Old Ray] #2821739
09/16/20 10:35 PM
09/16/20 10:35 PM
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96 is the last year the 6 bolt wheels can easily be change back to a 5 bolt. After 97, The front hubs and suspension was changed, and none of the 96 and older stuff works.

All the Dakotas have the raised rear frame. It kicks up to cover the fuel tank, which is inside the frame rail, then just does not drop back down. If you have a high side box from 50 or so, or newer, you can get a 13" deep box. Its the nature of the beast.
Whichever frame you use, expect to have to modify it to match the wheel base of whatever body your going to use. Its easier to shorten a frame then it is to make one longer, and between the front fuel tank cross member and the back of the cab is the easiest place to shorten one.
You also probably should expect to move the firewall back into the cab at least an inch or two, other wise things like firewall clearance, radiator clearance, and front axle position in relation to the wheels in the front fenders gets really close.

I'm currently putting a 49 Dodge on a 93 4x4 chassis, and I'm using the 318 drive train out of a 95 Dakota. The 48-53 cab and front clip are about the shortest front end Dodge made. I have the entire drive train bolted to the factory Dakota stuff, and I used a Dakota firewall spliced into the recessed area of the 49 firewall. I wish I would have moved the firewall back another inch, or two. The motor to firewall is very close, and I had to cut the top 8" off the Dakota radiator support. I also had to notch both corners of the nose to clear the radiator. There is about 2" of clearance between the radiator core and the front nose piece sheet metal. There won't be an AC condenser in there. I also have to fabricate all the metal to attach the nose to the radiator support. The truck is nearly to fire up and move under its own power.
When I get to the point it moves, I suspect I'm going to have to cut the front fenders and move the wheel arches 2" towards the rear, and probably raise them up an inch or two to clear the 235/ 75/15 tires. Had I moved the firewall back into the cab 2". I would have moved the cab forward those 2" and I would have had more room in front of the radiator, and the tires may have better cleared the fenders, maybe.
Both the Dakota donor, and the 49 have 6 1/2' beds. I'm going to use the box floor and front panel and cut the sides off to mount the 49 box sides. The Dakota rear axle (96 6 bolt) is a couple inches narrower then the 49 was, so I will have to cut the 49 box sides around the tires and wheels for clearance. When I cut the Dakota floor, I will also cut the wheel tubs to match up to the cuts in the bed sides.

Pictures:
1) shortened frame. Notice how high the cross member is just in front of the rear axle? That cross member is one of the two the Dakota fuel tank is strapped to. One of the bed cross channels actually sits down inside of that cross member. That little nub thing ahead of the raised fuel tank cross member is the front box mount. This frame was cut between that front box mount and the raised cross member. The standard fuel tank still bolts into place without modification.

2) this is my cab with the firewall and the trans tunnel cut out. I should have trimmed back to the flat pieces, and recessed the entire firewall back 2".

3) Dakota firewall welded in place. This cab had a pretty heavy gauge floor pan installed that I didn't remove. Modification was required to get the lower Dakota's firewall to match up with the cab floor pan.

4) The process of setting the cab on the chassis takes time. You have to trim, and cut stuff to get it to fit at all, then you get to cut it some more to get clearance as you slide it around to get it into position. This is a good picture of how the fuel tank fits on the frame. You can also see I had to cut a chunk out of the back of the cab, and a section of the cab rear floor to clear the fuel tank. Inside the cab, you can see the firewall is still intact, and the hole for the trans is pretty small. This may have been only the 2nd or 3rd test fit. All the cut holes ended up being about 3x larger then what they were on the 1st cut, but you go at it slow, so you keep everything as close as you can. The motor was bolted to the frame, so you measure, and cut small holes, then see how it fits. Mark how much more you need to cut, lift the cab and roll it back away from the frame and cut to your marks, then test fit again. i lifted the cab off the frame at least 5 times that day. At the end of the day, the cab was sitting on the blocks to get the firewall cut out (picture 2).

Don't be mislead, this is not a simple slam it together in a few hours project. This is the 5th one I've done. I'm retired now, I started this project July 8th, and have probably put in a good 25-30 hours a week on it. I started with an already shortened frame and a cab (and all the sheet metal) that sat on top of the frame, with the front cab mounts welded to the frame. I had a running, driving Dakota donor, and i have experience doing this. Realisticly, I'm probably 50 -60 hours away from driving it up and down my driveway. Then all I have to do is install glass, install wipers, fix the cowl vent, install a dash, do the interior, and do body work and paint. The goal is to have it a daily driver by spring, with or without paint.
I'll try to get pictures of the front end tomorrow. Gene

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Re: Frame swap question [Re: poorboy] #2821747
09/16/20 11:13 PM
09/16/20 11:13 PM
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Gene,
Thank you for taking time to explain a little of that and add some pictures as well. I know that this will not be a quick project by no means and have done some research on the process, videos don't make the job easier though. I do know that I have to shorten the frame and if I go with the 88 it will be about 4 inches to make everything line up and have the wheels located in the fenders properly. I did not know where would be best to shorten it so thanks a ton for that information. I had also planned on trying to use the Dakota firewall and maybe the floor itself if I can get it to line up right but we will have to see about that. I am building a 360 to replace the 318 that is in the truck now and did expect to have to relocate the firewall I just had no idea how far. With the 88 I am looking at the steering column looks very basic and I was curious if you used any of the dakota steering columns in any of your builds to line up and convert to power steering? Again, thank you so much for the time and help with this. I will make sure to have a post on here as I go forward and if you don't mind I may ask you for advice if I get stuck.

Jeremy


1957 D100
Re: Frame swap question [Re: JWK57D100] #2821842
09/17/20 11:30 AM
09/17/20 11:30 AM
Joined: Sep 2016
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British Columbia, Canada
Old Ray Offline
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Gene is my hero and I am not worthy.

But to just offer info on the other alternate you mentioned I did the Dakota front frame clip on my '56 wagon.
Many benefits (for me), the frames are exactly the same width (@ sweet spot) and no rear frame mods required for the car body.

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Last edited by Old Ray; 09/17/20 11:42 AM.
Re: Frame swap question [Re: JWK57D100] #2822073
09/17/20 09:41 PM
09/17/20 09:41 PM
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Jeremy, I've used the Dakota column on the last 3 frame swaps, because I've also used the Dakota wiring harness to keep the efi. After 92 or so, the Dakota column had a factory air bag. When they went to the air bag, they also added an under the dash black box that everything under the dash runs through. With the addition of the black box, all the in truck switches changed from simple off/on to a variable voltage reading. Turn the wipers on, you get a change in the voltage coming from the switch, change from low speed on the wipers to high speed results in another voltage change, and if you shut the wipers off, you get another voltage change. As a system, it all works, but to use components individually it all becomes a nightmare. After market wiring, switches, and the components they operate would solve the issue, but the last 3 conversions involved a functioning system with very good wiring and I was too cheap and in too big of a hurry to change it all out.

I've also used the Dakota floor pan (if it was good), when it made sense. I did a 39-47 and the Dakota pan was just too wide, nothing really fit or lined up. I probably could have used the Dakota pan on my 49, but the original floor was replaced at one time, and they used 1/8" plate. I did use the firewall, and the trans tunnel (back to the 49's seat bracket). I also used the Dakota HVAC box, it bolted to the firewall intact (the 39 cab was not wide enough to use the Dakota HVAC box, and my 48 Plymouth coupe was just short of being wide enough, on it I cut off the recirculating duct and redid it). The 49 has a functioning fresh air vent that opens and closes on top of the cowl, I'd sure like to keep that, but I'm going to have to redesign the lever that opens and closes it because the Dakota box occupies the area the lever used to reside in. I also will be using the Dakota AC (if I can figure out where to put the condenser) and that will need a fresh air inlet to draw outside air during both heat and AC cycles. I'm still giving both the fresh air systems a great deal of thought.

A windshield wiper system is another project. Everything involved with the original truck wiper system was gone on my truck. Those wiper would stroke in opposite directions. I can use the entire Dakota system, if I make brackets and re-engineer everything. All the modern wiper stuff strokes the wipers in the same direction. On my coupe I installed an idler pivot that changed the direction of the one wiper arm, it works, but requires a consistent re-lubing. Something I won't be able to do on this truck.

If the high box floor really bothers you, you can also use the Dakota front clip and splice it to the rear frame on your 57. Behind the trans cross member, under the cab, would be a good place to splice your frame in. If you splice it under the cab, all your original springs and box mounting will still work. You won't be able to use the Dakota fuel tank, but other tanks will work. You can get other tanks for use with EFI electric intake fuel pumps, or for carb use with or without an in tank pump.

I'm willing to help with anything I can, I'm on Moparts nearly every night. Gene

Re: Frame swap question [Re: poorboy] #2822124
09/18/20 01:13 AM
09/18/20 01:13 AM
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Thank you both for the advice and help.
Gene,
The steering column having everything already wired was another reason why I wanted to use the dakota column and my lack of patience for trying to wire it all again.. That and it would also be easier when I go to connect the power steering and everything if I just use the existing column, like the brake system. I do have the motor and the windshield wiper assembly minus the actual blades so I will have to figure that out with the newer column. I'm not good enough to try and fit the ac system in this one so I will have to just handle the heat or keep it home that day I guess. I want to try and use the firewall and as much of the floor pan/trans tunnel as possible to avoid having to fabricate a new one. When you used the floor pans before on your builds did the cab mounts stay intact with the pan or did you still have to fab new ones?
The higher bed floor doesn't bother me that much really to be honest. I considered just doing the front clip but with the dakota drive drain being offset to the right I didn't know how much trouble that would have caused with lining the trans up with the rear end later in the build so for me it seemed easier to just use the whole frame, insert any advice if I am looking at it the wrong way or over complicating it. A question for you and Ol Ray both about the frame shortening and front clip swap. I have welded most of my adult life and am confident in my welds but not in my ability to align the frame correctly. Did either or both of you do your own modifications on the frames or did you have someone do it? The shops here in California want half an arm to just shorten a frame by 4 inches so I am just curious how you guys went about it.

Jeremy


1957 D100
Re: Frame swap question [Re: JWK57D100] #2822185
09/18/20 10:14 AM
09/18/20 10:14 AM
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British Columbia, Canada
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I think my Donner was a '92 with no air bag / variable voltage but I will confirm the year if it is not. I used the OEM column but it is never easy into a different body.
This is the only picture I have of the column at this time.
As far as the frame splice, after much research and consultation with Gene, and me over complicating things, the key items where:
compressing the front springs by redi-rod (all thread) to ride height, taking the front of frame / A arms angle measurements, and most critical squaring the frame to the original wheelbase.
All the other items will have to be adjusted to fit, engine setback, etc. My car was a registered vehicle and did not require an inspection.
Your frame probably is a different width so some of this is not applicable. I have a rambling disjointed build thread here:

https://board.moparts.org/ubbthread...ut-for-dakota-sub-frame.html#Post2443761

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Re: Frame swap question [Re: JWK57D100] #2822352
09/18/20 05:59 PM
09/18/20 05:59 PM
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Dandridge TN
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Here is a link to a build I did back in 2013 you may want to read. I have put over 53,000 miles on this build with no issues https://board.moparts.org/ubbthread...n-a-2005-dakota-chassis.html#Post1313950

Good luck on your build. It’s a lot of work and a real adventure but worth it in the end.

Re: Frame swap question [Re: JWK57D100] #2822453
09/18/20 11:29 PM
09/18/20 11:29 PM
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Jeremy, Mopar as been offsetting the drive train in the frame for years, as have most manufacturers. Unless you have a really short driveshaft, the U joints can accommodate a 30 degree angle at each end, as long as the angles are not trying to bend the shaft into a U. That would amount to about a 3"-4" offset.
Usually, when you do a frame swap, you usually have to move either the cab mounts on the floor, or you have to move the cab mounts on the frame, and a lot of times, you end up moving both. The front cab mounts on a Dakota are way out wide, and most of the older stuff isn't wide enough to use the Dakota mounts in their original position. If, for example, your 57 cab is 60" wide, and the Dakota floor pan is 65" wide (not actual measurements) your going to have to trim the width of the Dakota floor to fit your cab, and what you trim off will probably be at the cab mounts on the Dakota floor. Very seldom is the rear cab mounts in the proper position.

Cab mounts can be pretty simple. You add a bracket to the outside of the frame, a 3" wide piece of angle iron will work, or a 3" channel iron will work, or even a 1/8" thick piece of formed metal with side walls and a top plate. The end of the bracket needs to stick out from the frame somewhere between 3" and 6" (though I've made them longer then that), and about an inch in from the outward edge of the top flat plate you need a 1/2" hole. You want that bracket the same on both sides of the truck, and at the same location on the frame. Then you need a rubber bushing, flat rubber, a block of wood, or an actual body mount rubber bushing (I prefer the actual cab mount bushings) that is at least 2" on diameter with a 1/2" hole through the center to act as a cushion. The top of that cushion needs to be above the frame, and it will sit on top of your bracket that is welded to the side of the frame. You need the place on the floor pan that lines up with the hole in your bracket to be reinforced, read that as at least double floor pan thickness, I use a piece of 1/8" flat that is larger then the cushion diameter. My preference is for that reinforcing plate to at least be tack welded (I fully weld mine) to the floor pan with a 1/2" hole that lines up with the hole in the frame bracket.I use a 1/2" grade 8 bolt, with a flat washer under the bolt head, push it through the hole in the floor pan, through the rubber bushing cushion, and through the bottom bracket. Then I add another flat washer, and a luck nut. Tighten the bolt until the rubber just starts to compress. You can get way more fancy if you wish. You can add a recess so the bolt head is below the floor pan surface, and you can add a rubber under the frame bracket. Actual cab mount bushings have a step bottom that would fit into a larger diameter hole cut in the frame bracket.They also have a steel sleeve the bolt passes through, and usually there is another piece of rubber that goes under the frame bracket with a very large formed steel washer. The actual body mount bushings cut down on the chance of the bolt rubbing on the sides of the hole and making noise. That also help to keep the rubber from being squashed too much and having it start to fail.

Frame shortening: All the area around the weld joint needs to be cleaned to shinny metal, inside, outside, for at least a 1/2" either side of the weld. You have to make sure both frame rails are the same length, and are square with each other. You also need to be sure the upper control arms on the Dakota front suspension maintains the same degrees of angle. They are not set flat to the earth, the front control arm bushing is higher then the rear bushing to get a proper wheel alignment and good driving traits when your driving. All frames have alignment holes formed in them. Their purpose to to get the vehicle pulled back to straight after a crash. Those alignment holes match the same location on both sides of the frame and there are 8 or 10 pairs of them on each frame. Find a pair on the front clip, well forward of where your splicing (or shortening) the frame from. There should be a pair just before the frame kicks up to accommodate the front suspension. Locate a pair well behind where your going to splice. Mark both pairs so you an find them easily. With the frame on stands (8 of them, 2 on each side of the frame cut lines, and two on the front section, and two on the rear section, once the frame is cut, the jack stands will be the only support for the frame sections) set it up so the rails are level. Check the frame for straightness, measure each side from the front alignment hole to the rear alignment on the same side, and write that number down. Now do a cross measurement from the front hole on one side to the rear hole on the other side. record those numbers. The measurement from the front to the rear hole on each side should be the same (+ or - 1/8"). Both cross measurements should also be the same (+ or - 1/8"). If they are not, you need to get your frame straightened before you cut it.

So the frame is straight. Lets say I'm going to shorten the frame 6". I will clean up the area that will be welded on both edges before I cut it. Then using a square, I will draw a vertical line at least 4" in front of where I'm going to cut and remove the chunk. Then, again using the square I will draw another line at least 4" behind where I'm cutting the chunk out. That is going to give me two square lines 8" apart, after the chunk is removed. I'll do this on both sides. Carefully measure out where the cut lines will be made. It may be best to leave yourself a little extra 1/*" off the cut line, then grind the extra off to be sure the cut is in the correct position. If the jack stands were properly place, once the first cut was made, nothing should move after the cut was done. Make all your cuts and clean up the edges. Slide the front frame and the rear frame section together. Make sure everything is still flat and aligned. At this point I will clamp a short piece of tubing or angle to the outside edges of the frame rail (on both sides), and I will also clamp a tube or an angle to the bottom edge. Then I will measure the distance of my drawn lines. If that is good, I will do the measurements of the alignment holes. If we are still good, tack weld all 4 corners of the splice on both sides, and check my lines, then check the alignment holes. Then I will make a series of short 1" long welds (the same area on each frame fail), checking my measurements after each pairs of welds. After a couple pairs of welds, I will remove my tubes angles and clamps. Are you getting the idea how badly I want to be sure is staying square? Repeat until its fully welded.
After the welding is done, and the frame is nice and square, I will probably also add a diamond shape piece of 1/8" plate (fish plate it) over top of the joint. The place I usually do my splice is at the channel section of the frame. Often times I will use the piece I cut out to box the channel section. Gene

Re: Frame swap question [Re: poorboy] #2822519
09/19/20 09:47 AM
09/19/20 09:47 AM
Joined: Sep 2016
Posts: 201
British Columbia, Canada
Old Ray Offline
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bow bow bow

Re: Frame swap question [Re: poorboy] #2822700
09/19/20 07:12 PM
09/19/20 07:12 PM
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JWK57D100 Offline OP
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Gene,
Thanks for all the information, most of that makes sense without actually looking at the frame right in front of me. Found a 91 regular cab, long bed that I should have by the end of the weekend. Let the fun begin and Ill keep plugging away in here for advice and updates.
Jeremy


1957 D100






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