frame swap for a 4x4

[Dieselwrencher]

I always heard that the 3/4 ton 2wd leaf spring trucks were the same frame, structure not hole alignment and such, as the 4x4 trucks. The reason I measured the two trucks I have is because this will give frame specs to the two frames I have. And I am betting that the blazer frame is the same as a K10 frame, just shorter. I have Never seen a factory K10 with a frame as big as a K20 unless it has had a frame swap already.

[OrrieG]

I don't know where you are in Oregon but later this winter I will have a 74 K-10 frame available. I am pulling the engine, tranfercase and trans then advertising the rolling truck for sale. If no one bites I'll pull the axles, steering box, brake stuff and then scrap it. Body is rust bucket. ITs a long wheel base fleetside.

[prg machine]

so the 1/2ton and 3/4 ton frames are different dimensionaly or the same?
I am getting confused

[padresag]

they are more than likely the same . it is the capacity of the springs and axles that will make the difference. It is just that the 4 x 4 frame is deeper in the middle than the 4 x4
ron
note;I said more than likely

[FormerMember]

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[prg machine]

Originally Posted by OrrieG

I don't know where you are in Oregon but later this winter I will have a 74 K-10 frame available. I am pulling the engine, tranfercase and trans then advertising the rolling truck for sale. If no one bites I'll pull the axles, steering box, brake stuff and then scrap it. Body is rust bucket. ITs a long wheel base fleetside.

I don't believe the 74 will be a compatible frame

[FormerMember]

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[padresag]

"There is benefit to running a one ton frame and they do all have various height and thickness differences. 1 ton non-commercial use frame will be dimensionally the same as it's 3/4 ton brother, but 1/8" thicker. 4wd frames are 1" taller through the middle to provide room for the t-case. Commercial (C+C, Mil, etc) can be all sorts of weird. I put a commercial 70 2wd frame under my truck."

not trying to be smart with this reply. I cannot understand what is termed as a non commercial frame. most 1 tons built at that time were built for commercial use. they were mainly work trucks except perhaps for a limited nbr at that time going for RV use.
one could have ordered different w/bases and suspension options
there could have been custom chassis ordered for certain fleet applications.
Grendel ; it would be interesting if you could elaborate on this
thks
ron

[FormerMember]

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[prg machine]

I just wish mine wasn't bent

[FormerMember]

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[72-c20]

Originally Posted by Dieselwrencher

And another thing, you will need the bumper brackets from the 4wd truck in the front because 2wd and 4wd are different.

I thought the bracket difference was because of the frame, and the bumpers were all the same?

[prg machine]

Originally Posted by grendel

torch, hammer and a bit of elbow grease can fix that...

Seriously about the torch?? Heat on the frame won't affect the structual integrity and heat treat? Or is it common practice?
I will tackle about anything to save this truck, and I already have, but I was reluctant to heat the frame rails to get them straight.

Any frame metalurgists out there??

Any ideas accepted.

[FormerMember]

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[Dieselwrencher]

I used to work in a heavy truck frame shop. Without heating the frame rails you will more than likely never straighten the frame without damage to the metal and or the equipment. So yes you can heat them. I used to get the semi frames glowing red with about 25,000psi of force on them and would leave them until cool. On a heat treated frame, you do not want to quench them like mentioned. On these older frames it won't hurt them but I would just let it cool once put in a pull or bind used to help straighten them.

[Dieselwrencher]

Originally Posted by 72-c20

I thought the bracket difference was because of the frame, and the bumpers were all the same?

The bumpers are the same. But, the 2wd brackets go behind the rad support on the frame and on the 4wd they bolt right into the pocket of the rad support mount at the frame.

[Dieselwrencher]

Originally Posted by prg machine

so the 1/2ton and 3/4 ton frames are different dimensionaly or the same?
I am getting confused

I am guessing that the 1/2 ton frames and the 3/4 ton frames are different as frame channel heighth. I haven't seen any 1/2 ton 4x4 frames the same as my old 3/4 ton 4x4 frame was. I could be wrong but they don't look the same.

[padresag]

I will measure both a 2 x 4 and a 4 x 4 1/2t frame height tomorrow and if someone wants to measure a 3/4 4 x4 frame and post it and we can put this to bed
both of my frames are short w/b and 3/4t are all long w/b; so if someone has a lwb 1/2t 4 x 4 that will solve it all
ron

[prg machine]

good information all around to know what these differences are before blindly buying and swapping frames

[justcuz]

Originally Posted by Dieselwrencher

I used to work in a heavy truck frame shop. Without heating the frame rails you will more than likely never straighten the frame without damage to the metal and or the equipment. So yes you can heat them. I used to get the semi frames glowing red with about 25,000psi of force on them and would leave them until cool. On a heat treated frame, you do not want to quench them like mentioned. On these older frames it won't hurt them but I would just let it cool once put in a pull or bind used to help straighten them.

My experience also, do not quench, just let cool with straightening apparatus in place. Remove and measure. Most frame shops will work within a plus or minus 1/4" on 2wd stuff because you can make it up in alignment. On a straight axle I'd go for right on, but if your as close as an 1/8" or 1/16", I'd try and drive it and see what happens. You have done very well redoing the truck since the accident, you have nothing to lose by straightening the frame some more. Just be sure your wires, brake and gas lines are away from the inside of the frame rail before you apply the heat!

[prg machine]

Originally Posted by justcuz

My experience also, do not quench, just let cool with straightening apparatus in place. Remove and measure. Most frame shops will work within a plus or minus 1/4" on 2wd stuff because you can make it up in alignment. On a straight axle I'd go for right on, but if your as close as an 1/8" or 1/16", I'd try and drive it and see what happens. You have done very well redoing the truck since the accident, you have nothing to lose by straightening the frame some more. Just be sure your wires, brake and gas lines are away from the inside of the frame rail before you apply the heat!

Thanks for the good words.
The frame was off a mile in the begining and i got it close. It drives okay but favors pulling slightly right. I will more than likely pull the front clip off at some point and get back into the straightening .

I am still mentaly engineering making some tools to do this with a little more accurately than a tree, hammer, come-alongs and another truck pulling the frame to straighten. I have been advised to paint straight lines on the garage floor and use plumb bobs to get it styraightenend out.

[FormerMember]

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[padresag]

I did measure the depth of my frames and the 2 x 4 was 6" deep(about 10" behind the frt cab mount) and the 4 x 4 was 8" so there is a 2" difference between the frames
ron

[prg machine]

Originally Posted by grendel

I have a couple of long pieces of inch stock, that I've drilled holes and tapped through on the other side. I use those to straighten by clamping the frame rail between them, heating the frame and tightening. I'll either let it cool slowly or throw cold water on it to "shock" the steel's memory back to where it needs to be.

The proverbial light bulb just came on my friend! I think I lke your method. Sometimes thinking outside the box makes a big difference. All of this time I am thinking external tooling and attatchement points and you just got me thinking about using the frame itself as an anchor point for other tooling to work off of.
Excellent advice!!!!

[FormerMember]

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