I have a 1948 F6 I am going to shorten the frame for a 10' bed. What is the "best" method for doing this? Rolling the axel up and drilling new holes or cutting the frame and taking some metal out?

Thanks for the help!

 

Haven't done it for a truck that size but I did shorten an F-3 to convert it to an F-1. That operation required two cuts. One in the middle to take out 8 inches to get the wheelbase correct and another 12 inches off the rear overhang. Neither cut required any movement of suspension parts forward or rearward.

My guess is you will may have to do something similar with the F-6 but since there is no frame kick up (as I remember) in the rear you may be able to just move the rear suspension forward and cut off the overhang.

The big truck guys will be probably along shortly on this and give you some more definitive advise...

 

Above info is right on. If there is a kick up in the frame for rear axle suspension travel then cut the frame in the middle and shorten there, if the rails are flat then move the rear suspension forward and cut off the overhang.

 

There is no frame kick up as such like on the F1, and the frame top is flat. But there is a narrowing of the frame over the rear axle, as the lower frame rail is higher to accommodate axle movement.

This is on the F4 single walled frame. I'm just guessing F5 and F6 double walled frames are shaped the same.

 

If you decide to section the frame, come back and ask again for advice on easiest/safest way to do this.

 

It's harder than it sounds to move the suspension forward. To do it correctly, you'd have to remove all the rivets for the spring hangers and crossmembers, move everything forward accordingly, and drill and bolt everything back together. The part where you could run into problems is keeping the frame rails in the correct position as you take apart all the structure, and hope it goes back together the right way.

 

So would I be better off cutting the frame?

 

That depends, what wheelbase is the truck?

 

176" wheel base

 

Well, your rear spring shackles are more than 10' from the back of the cab (126"). So if you cut the back frame off at the very back edge of the rear shackle, you are over 10'. This would not even allow you room to attach mudflaps
The only way to do that right would be to move the rear axle forward more than 2'. My F5 is 158" WB and I could probably have squeezed a 10' bed on it, put it would have looked goofy.

 

If your F6 frame is double walled(I think they all are) that will add to the headache. Also there is a good chance of rust between the inner and outer rails.

Because the frame height changes as you go back, sliding the springs forward that far may not work.

Will the truck be used for heavy hauling?

 

I want the ability to pull a car trailer for hauling antique tractors. So not real heavy hauling.

 

IMHO yes, less work, better chance of good outcome. Double frame is the snake in the woodpile tho.
If it were mine, I'd likely just find another right length frame from a smaller truck tho.

 

This truck has no rust the frame it is in excellent condition. What would make a double frame harder than a single?

 

You would want to fish plate both sides of the splice. Difficult to do without separating the layers. If you could remove a section of the doubled frame at the splice, it would be possible to splice the two layers in such a way as to each provide the function of a fish plate for the other. I've never worked with one of these big job doubled frames, so I don't know what's involved with separating even a portion them. You really don't need the extra strength of that frame for use as a trailer tow vehicle, even the 1/2T frame is strong enough.