I would like to shorten the frame on my 1957 F600 from 154" wheel base to a 130" wheel base and install a shorter bed so the truck will fit in my shed better. I beleive I can fabricate the brake lines myself and have the drive shaft and PTO shaft shortened locally, but was hoping to get advise on how to best cut, reweld and reinforce the frame. Thanks

 

I believe they covered this sort of thing on the latest GEARZ show last weekend.
Gearz Episodes: LMC Truck: Shortbed Conversion | Stacey David's GearZ

 

Lets see if I can keep this short. Tools needed some kind of tall jack
stands or blocking, O/A torch, good half inch drill and quality HSS 1/2
drill bit, and a ruler. Jack up so rear wheels are just off the floor. Burn
off all rivits from spring hangers and aux spring hanger. Punch all the
rivits out. Remove rear drive shaft. Measure distance from front spring
hanger to where you want to be both sides mark with chalk. With two
people roll the whole axle assembly forward to the mark. Measure
again. Measure front axle center to rear axle center-both sides and
confirm this has to be dead center. Now let the truck down putting
some weight on the spring hangers. Now have a drilling party using
plenty of cutting oil. Make sure to use a pipe on the electric drill or it
will take your arm off. We tipically wrap a chain around the chassis
and stick a 2x3 through the handle of the drill with the chain wrapped
around the 2x3 acting like a drill press. A box of gr 8 bolts locks & nuts
thats done. Then remove the rear crossmember and move back to
to the same dimention it was origionally. Last will be the driveshaft.
At a 130" wheelbase Its on the boarder line of getting away with
one piece shaft elimiating the carrier bearing. you mention PTO?
that stays. To conclude it has been done to chop & weld the frame
I dont recomend that. Rather the suspension is moved keeping the
frame intact. Dont forget this is a double frame or should be so a lot
of cutting oil. The hardest yrs ago was a 50 F8-H which is a tripple
frame with a Truxmore suspension that was like 20,000 holes to drill.
Hard to beleive last one we did the fire truck, only one drill bit did
the whole job. Oh, last cut off the frame waste- grind and paint......

 

Big job - thanks for the reply. I will look into the method you suggest. I was thinking I could cut 24" from the middle of the frame, measure corner to corner to insure squareness, reweld and then box it all in. Never really thought about it but a small bench top drill press might work to drill the spring perch holes you were talking about.

 

I agree with Big Job's post . My shop just shortend a Pete for a customer . He wanted it for a farm hauler to haul tractors , sprayers , hay , ect . He got it cheep . It was Way too long for what he needed . We cut the axels loose , moved them farward ,choped the rear , redrilled and bolted everything back up . We rented a Sweet drill . It had an electric magnet that held it to the frame . It worked like a drill press , but used milling bits . Then we shortend the driveshaft and it was done . We made templets of the factory bolt pattern to aid the drilling .

 

Can you please explain the drill jig again - I am not visualizing the drill with the 2x3 and chain to make it work like a drill mocked up drill press. Thanks.

 

Best pic I could find:

http://www.ih8mud.com/tech/woody/images/soa/soa9.jpg

The 2x3 and chain are just use to stabilize a drill, aid in keeping on target, and prevent it from torque-reacting and tearing your arms off.

There are a lot of different ways to drill, these are just a couple, and probably some of the better ideas.

I like the suspension move. Frame integrity isn't a question in that case.

Also, you will need to shorten and possibly remount your bed and hoist.

 

Just a recap, this is hard without pics. Most half inch drill have a one inch
steel handle, which a pipe is slipped over that, that another guy holds
onto. the 2x3 doesnt have to be wood could be pipe. That goes
through the "D" shape handle -top of drill- the end goes through the
chain which is wrapped around the frame. Adjust chain so the pipe or
wood is about parralle with the frame. The drill man controls the drill
on center pulling the trigger while putting pressure on the pipe or wood
with his leg,
while a helper is holding the drill from spinning . Of course there are
magnetic drills for this big bucks.. This costs -o- . I do know if you go to
chopping a piece out & welding and going commercial watch out for the
truck Natzi s. Thats why newer trucks usually have a decal no welding
on frames. This is the best I can do without pics. sam

 

Just keep in mind that it is usually easier to drill holes than to do a full penetration weld on a frame. A tip on the drilling - find a bushing (bronze, steel, whatever) with a 1/4" hole that fits snug in the holes of the spring hangers. Put it in a hole as a guide and then use a 1/4" drill bit to drill a pilot hole. When all pilot holes are in, use the final size drill to open up all of the holes. Makes the drilling a bit easier.

Also, many tool and equipment places rent magnetic drills (portable mag drill press), or heavy duty 1/2 or 3/4 inch drills if you do not have one of those.

 

That is what we rented when we bobbed one . Well worth the money spent !

 

Thanks - I was getting hung up on the "D" handle drill. The 1/2" drill I have is a pistol grip with handles you can screw into either side. I forgot about the heavier duty D handle drill but we might have one at the shop I can borrow over a weekend. I believe I understand now. Too bad they don't have a mag drill too I'll try to post a before and after picture. I really do appreciate the advise.

 

OK - quick update. Traded the original 13½" bed for a torch set. The original bed is now sitting on a local farmers running gear being used as a hay wagon. Got a nice used 10 x 8 steel bed for free from a relative who bought it at a farm sale and never used it. I noticed that the s/n plate on my truck says I have a 130" wheel base but my wheel base actually measures 154". With the old bed removed I can plainly see where some one simply cut the frame in half and welded in a 2 foot section on both sides - no gussets, no boxing, no plating. Therefore I have decided to simply cut the 2 foot section out, weld it back together and reinforce it with a diamond shaped fish plate at the seam. Unfortunately because the structural frame rail height is different at the back of the frame vs the front of the frame moving the rear axle forward is not an option (it would give me a raked looked which would not work for me). Since the truck has lasted for years hauling wheat with weld in extension I figure it should last several more years if I use a similar method to shorten the frame.

 

Thank you for the update. A good weld is as strong as the original metal.

 

Another option to using fish plates would be to have frame sections bent to fit inside the origional frame . This makes a tough repair and adds to structural integrity. This on the inside and a fishplate on the outside makes a strong frame.

Have A Great Day --- Hotwrench

 

Good luck ! May your weld be good , and hold long . I see issues sometimes with the surrounding steel breaking after use/load . I would reinforce if going this route .