Coil driveshaft on leaf truck?
 

I have searched and couldn't find any information on the subject. I have a 70 lwb with leafs that I am going to cut down to a swb. A swb driveshaft poped up for sale locally from a coil truck.. Both trucks having th350's I'd think it would be a direct swap unless there is a difference I am unaware of.

Re: Coil driveshaft on leaf truck?
 

Save your money and time until you have it all done.
Then measure your driveshaft length.

Re: Coil driveshaft on leaf truck?
 

The carrier bearing and mounting brackets are different for Leafs and Coils (Unless you have a 3/4 Burb). If you have the I-beam style mounting bracket (1/2 tn coils) laying around then you might be able to get it to work after you remove yours.

Smitty

Re: Coil driveshaft on leaf truck?
 

The carrier bearing and brackets are not different...but there are 2 carrier styles with corresponding brackets, they are fitted to trucks based on engine size and tonnage.
They are interchangeable.

Ive never checked but the placement of the crossmember could be in a different location making the driveshafts not interchangeable.

When making a short bed truck only the front half of the driveshaft needs to be shortened. Its probably more cost effective to have it shortened.

Its actually pretty easy to do at home if you take careful measurements. Ive done dozens of them, never had one with any vibration issues either.

Re: Coil driveshaft on leaf truck?
 

I agree with almost everything you say, except one thing.

Since all factory trailing arms are the same length, doesn’t that mean that the trailing arm/steady bearing crossmember is also always the same?

Re: Coil driveshaft on leaf truck?
 

Not trying to start anything but if you can mount an I beam style carrier bearing straight to a Horseshoe Style Mounting Bracket without modification I would love to see it. In my book that makes them different. From the majority of coils I have done they come with the I beam style carrier versus the Leafs having the Horseshoe Style with the exception of 3/4 Burbs. The shafts have different lengths also from what I have done so it is just not plug and play. They OP wanted to know if he could just change out shafts straight out. The systems are different so it will not just be un-bolt and re-bolt. If he has the ability to cut and weld up a shaft then why not just do that to the original one? I don't think that is the case here so that is why I posted my response.

Smitty

Re: Coil driveshaft on leaf truck?
 

OP is leaf and is checking if coil driveshaft will work...it will if the crossmember for the carrier bearing is in the same place. I dont know if they are but i suspect it may be.

Fore and aft carrier bearings and side to side carrier bearing driveshafts can be switched out if you change the bracket. The fore and aft bracket is usually riveted in place. Side by side is bolted. Switch the bracket and the driveshafts interchange.

There are 1330 and i think 1350 rear u joints so be careful there. The front and center u joints vary too so if you plan on switching yokes they may not interchange.

Re: Coil driveshaft on leaf truck?
 

[QUOTE=randy500;8647465]

Fore and aft carrier bearings and side to side carrier bearing driveshafts can be switched out if you change the bracket. The fore and aft bracket is usually riveted in place. Side by side is bolted. Switch the bracket and the driveshafts interchange.

/QUOTE]

Yes,
If he gets that mounting bracket for I Beam Carrier "Fore and Aft" then it may work depending on how the frame is cut down if his GMC (Which every half ton GMC I have ever owned has the Horseshoe Style "Side by Side") bracket has to be changed out.

Smitty

Re: Coil driveshaft on leaf truck?
 

[quote=71meangreenc10;8647495]Probably every gmc you had was leaf because its standard on gmc which also indicates leaf trucks use the side to side horseshoe carrier....a much better system. Leafs are heavier duty and so is the side by side driveshaft.

chevy is standard with coil spring.
On chevy half tons i only see the side by side driveshaft on small block 4spd and big block trucks, all others have the fore and aft light duty carrier bearing.

So there you go, lots of info for the OP about driveshafts.

Re: Coil driveshaft on leaf truck?
 

As far as the OP being able to shorten a driveshaft.....if you can shorten a frame you can shorten a driveshaft. A driveshaft is much easier than shortening a frame, people are scared of it because of balancing...

Balancing is mostly done because the shafts are made in a production environment, very quickly and not so precise therefore the shaft is balanced to make up for loose tolerances.

Quick instructions on driveshaft shortening....

Maintain original yoke orientation to the tube by marking a scribed line prior to any cutting
Cut the tube, make it square checking it with a combo square.
Cut the yoke off with a cutoff wheel at the outer edge of the weld.
Insert the yoke into the tube, square it visually and with a measuring tape if possible to the tube and then tack and finally weld solid.

If you can, cut the yoke from the tube cutoff in a lathe, the lathe cut gives a straight cut line to line up to the tube, shortened shaft should be in better balance than the original shaft if out of balance was due to misaligned yoke.
.

Re: Coil driveshaft on leaf truck?
 

Thanks for the info guys. I knew there were 2 different carrier bearing styles but didn't realize they were leaf/coil specific.

Making my own mount for the "I beam" style wouldn't be an issue but doesn't seem worth it to switch to a weaker setup (I've dealt with them before).

Re: Coil driveshaft on leaf truck?
 

I had a leaf sprung rear in my 1972 GMC C15 longbed with the "horseshoe" style carrier bearing. When I wrecked the truck and bent the frame, I got a 1969 Chevy C10 longbed coil sprung frame with rear end that still had the mount for the I-beam style carrier.

When I swapped all my 1972 stuff over to the 1969 frame, I used my 1972 driveshaft with the correct mount for the horseshoe style carrier bearing and bolted it in the 1969 frame after removing the I-beam style carrier stuff. I also had to swap the u-joint yoke at the diff with the larger one from 1972 that was on my original diff. Everything works just fine and I have had no issues once i got the driveline rebalanced (as I had a vibration).

So it is possible. There should be a few pics of it in my build thread (link in my signature line).

Gary

Re: Coil driveshaft on leaf truck?
 

The answer is yes or no depending on the donor vehicle. On a leaf spring truck you will need the rear shaft to have a slider in it which 1/2 ton Chevrolets don't have. If it is a factory 3/4 ton then the driveshafts may swap. But 3/4 ton short boxes are few and far between. Here is a thread on the subject, see my post #11 for more information on which style gets used where.

http://67-72chevytrucks.com/vboard/s...arrier+bearing