So I think the very first thing I'm going to do on Abby is shorten her. A 154" wheel base makes for a very big truck, (not to mention its a couple feet past that) and this unfortunately makes it more inconvenient to use, meaning I would drive it a lot less. I plan to shorten it up and make a custom step-side bed for it. Large trucks done like this just look wicked to me.

So before I can properly make the bed or anything else, I'll need to figure out how much shorter of a wheel base I want as well as doing that first. I am thinking of going off of the long bed wheel base length of 118", however thats not set in stone, I'll need to take a few pictures when it gets down here and photoshop it till I've got it where I want it. I figure if I change my mind, again, and want to swap out the chassis the bed will be the same as well because I'd swap to a large 4x4. However I am thinking with it being shorter and not having 9000#s on the back of it, it will drive just like any other old truck.



So my question is more of whats involved on shortening these larger trucks. By the look of the rear suspension I have 2 sets of leaf springs per side and I can only see two small bolts holding each perch on.

I figure I will need to get everything measured and then re-drill the holes and move it forward, then shorten the drive shaft accordingly.

However, I do know that the F-600 has an area above the axle that is shorter than the rest of the frame. It seems to bolt on past this on either side however, so I am thinking it is manly for "bottoming out" reasons, only an inch or two shorter.

I know some people cut the frames and then reweld it, using a fissure plate. I do not have a welder currently that can weld this thick of a steel as solid as would be needed. The 600s have thicker frames, its not just a standard frame. This would be something I would have to pay someone else do to, and I have no idea what that would run (anyone want to venture a guess or know?)

I am thinking it would be better to just redrill the frame, but it's not something I've done before. It seems simple enough but I would hate to get half way through it and realized I've done something really stupid. I know a couple people on here have done this and I would love to hear from them, especially if its been done on a big truck. I'm getting closer to doing this and would like to gather as much information about doing so before I do. Nothing worse than crippling your truck and running out of money to fix it, lol!

I'll post a couple pictures I managed to take while up there, still waiting on getting it down (sigh, only been since February! And I searched since the May 2008 for a '56)

And just out of curiosity for other big truck owners, any idea what the price of tires run on these?


Ideas? Pictures? Warnings? How-tos? Anything appreciated. Thanks

 

Couple pics:





These pictures are quite larger on my computer so I can get a closer shot of anything if needed. By the looks of it only the bottom leaf springs are attached and the other brace looking part is more of a stopper. It also looks like they didn't attach after the indentation, meaning it would raise the rear up a little bit. Not something I see as a problem.

 

Big trucks are shortened or lengthened all the time, made into dump trucks - usually longer, or highway tractors – usually shorter by truck frame shops. It is my understanding that the frames are cut in the center and slipped together or extended with a frame splice welded in. I understand your wanting to move the suspension instead but I would think that would be more work and not for the faint of heart. I would check out a truck frame shop. (and get them to do it) The drive shaft has to be shortened too.

 

hi stephen,imo what you want to do sounds doable,the wheel base on my 50 m-68 is 122",with the express box.this works good for meas i can fit full sheets of plywood and such.that is 32"shorter that what you have how,im thinking if you go down to some "stock" length maybe you could just swap driveshaftsto keep that part simple.
what tranny do you have.also are you going to put the other hafl of the dullies back onor change the rearend as well.the handers for the springs sould have rivets and not bolts and there sould be 4 on each hanger(but i could be wrong).so if you slide every thing ahead on the frameand redrill the holes be sure to use all new #8 bolts(sorry if you already how this,but you how).with the frame being taller there ,this will give you a little rack look(i think that would look cool)
im just wondering about axle clearence if the back spring perch doesnt come forward enough to get on the same striaght part of the frame,if you understand what i mean.
i hope this may help some.

 

Thanks for the replies guys. From what I've been checking shortening the frame seems to be the way to go. Though I might have to move it forward and rebolt it as where I have to work I can't leave it looking undrivable

If I do cut the frame it seems doing a over lapped area (sorta like a sideways "Z" cut) seems to be the way to go. I'll have to go an weld some 1/4" in my shop to see if my welder is still up for it, I need a new one bad, lol... if not it seems I should be able to get it where I want it, tach it, then drive it over to a place that has a welder than can get enough penitration, or just rent one for a day or something.

 

you seen the pics of my f350 stephen and i cut it and shortened it . it was almost 30 foot long when i got it , and it became a long bed pickup . z cut 'tween the cab and rear suspension , fissure plates as i wasn't taking any chances , and boxed { he-- it was already heavy and was gonna be pulled around by a real engine aka fe big block so who cared bout a lil' extra weight ! }. it was strong and the way to go . it's done all the time as mentioned before to heavy trucks , and seeing as you are a blacksmith and a great working knowledge of mettalurgy it shouldn't even make you sweat . the frame rails on it were heavy , i think 8 inch channel . the f-6 i had was i wanna say 10 inch channel ??? might be wrong on both as my age gets in the way of clear thought ................ i ditched the overload packs in the rear , and took the spring packs apart to remove some leaves front and rear , have this obssession with lowered vehicles ......................... if it'd been finished i will say that it'd carried more weight than any newer one ever will as even with springs removed i swear you coulda put mine and a couple of neighbors whole houses on the rear and trundled off like they weren't there ........ it's not as hard as ya think as with the frame more or less being a straight shot { i left the rear suspension as mentioned and its " kickup " intact } it's just getting her level from side to side etc. lots of really big jackstands and a couple sets of extra paws will do the trick . i can't wait to see yours done ! i still wanna go back and find another myself and finish it this time ....................... used a plain ol' lincoln 220 volt arc welder myself , dont know how to use any of the fancy stuff available nowadays .

 

I found this on the web it might be helpfull mind you it is a ch@y http://67-72chevytrucks.com/vboard/s...d.php?t=123624

 

Chopping the frame with a "horizontal Z" and moving the whole rear end forward with the kick up and spring perches intact is the way to go on this. If you have a 220 welder you should be able to do it. I don't imagine the frame is thicker than 1/4" so chamfer the frame edges and run a bead inside and out and do it in short bursts to keep from warping and you should be set. If you are nervous afterward then you can always weld a plate to reinforce after grinding the welds.

For my frame work, to facilitate leveling, I bought some heavy duty RV leveling jack stands with the screw pads on them and made saddles to fit the frame so the frame would not slip off. They are infinitely adjustable and made getting it level side to side and front to rear very easy.

 

i wouldn`t cut the frame! index your frame at a few spots bolt hole(reference point) or something like that and take and mark down the measurements,cut out your rivets,move out the suspension to where you need it,mark the holes,if you can get a magnetic drill (makes it 100 times easier to drill) drill the holes,bolt in the suspension,cut the driveshaft and your done! at least this way you don`t have to sever a completely good frame,i`ve done 6 grain/gravel trucks this way,the only time i would cut the frame is if i had to add a piece to lengthen the frame

 

Thanks for the advise and link guys!

I'll have to give it a little throught on how to go about it, how I'm currently set up as far as where I have to work will effect it all quite a bit.

 

I agree with this method and if you need room for suspension travel you could always do a c-section and box that area.

 

looking again at pictures of your frame,(first one ) looks like you have holes already punched in the frame to bring the suspension closer?
you`d have to check this out and check if it would put you at the right length yoiu want

 

Thanks for the help guys.

No idea what those holes originally went to, I don't think I'm so lucky as to have them be something that would work for me unfortunately, lol.

A lot of people on the HAMB where saying to do it by cutting it, but to be honest it just seems in this case to a little wiser to just redrill the holes. For one I don't have to cut the truck in half to do it, worry about if its lined up even again, if the welds have the penetration I need them too or anything else. Not to mention I don't really have a place to work on it, I live in Wyoming of all places, you would think I would but nope, lol. Dead center of town. Redrilling the holes allows me to get a lot done before it's not drivable (or rather at a phase where I can't drive it). It might make for a little bit more of a rack (which I don't see as a bad thing) and I suppose there becomes the risk of bottoming out a little more, but think of how much weight you would have to have in an 8' bed to do that, I'd need to be moving a massive bronze statue or something, lol, and even then it's really not that big of a deal and I'd be more likely to put that on a trailer...


Anyone have any tips or possible ideas on how to figure out where all the holes go before taking it off the rear? I suppose I could just figure out exactly where the first bolt should go, then move it forward, bolt it down then drill the others accordingly.

Anyone know where to get those bolts and what exactly I need by chance?

Also, anyone have their driveshaft shortened before, any idea on cost? If I had a metal lathe I'd do it, but it seems like a bad idea to cut it without one.

 

The only concern I would have with removing the rivets to re-bolt the differential further up the frame would be the taper of the frame.

Moving the mount points will change the angle of the spring hangers in relation to each other and in relation to the frame and will raise the hangers. This will raise the rear of the truck and in turn change the pinion angle. You can probably fix that by removing and re-welding the spring mount pads on the differential with the pinion angle reset properly. It just seems to be a more elegant solution to section the frame and move the undisturbed springs, hangers and differential forward to reattach.

If you are dead set to move the hangers instead, then figure out how much shorter you have to go. Remove the rivets by grinding the heads off and driving them through with a punch. Then measure forward from the original hanger holes placing them the right distance from the bottom of the frame and use grade 8 bolts to reattach the hangers. I would also use self locking nuts and Red Loc-tite on all of them.

As to the drive shaft, it would have to be shortened either way. It's best left up to a professional to shorten, re-balance and ensure that the pieces are welded back together in phase.

 

either way your pinion angle will change,when i asked about changing over to a 9" on my 1 ton someone suggested a 3 degree wedge between the spring and pad,im sure you can get different degrees to suit what you will need.
also if you go down to a stock length on the wheel base it will make stuff like the e-brake and getting the axle centered for your new box easier.imo.