47-59 How to fix rear cab seam??

[smoknbarrels]

So I have done numerous patch jobs, rocker panels, cab corners and so forth… but that seam just under the rear window, bolting the top and bottom of the cab together is completely rusted through, the whole width of the cab!
Is there an easy fix to this? Or do I need to replace those massive roof and back panels? Seems expensive and excessive doing it that way?
Seems a lot of these trucks have rust pouring out of that joint.
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[mongocanfly]

Pictures?

[dsraven]

gotta have pics and a better explanation of what you're working on. AD I guess. inside or outside of cab? whats left for metal around it?

[smoknbarrels]

The curvy part which is about 2 inches tall, the whole width of the cab is nearly completely rotten, can even push your finger through it..

[dsraven]

Seems like you have a big job ahead. Replace the upper and lower sections of the rear wall. Not cheap just for parts, replace cab with another from a donor, registration issues to keep in mind, replace cab with aftermarket part, not cheap plus registry issues against, repair with home made patches or strips you have custom made. Labour intensive but way cheaper in you have lots of time and patience.

[mongocanfly]

I knew the area you were referring to, just wanted to see how bad it was..
that's bad..
Most of what I've seen done in that seam is to weld it solid...I dont know if theres a patch piece for that or not..
As bad as it is, it would be best to have that seam sandblasted ..that would show what you have left to work with

[dsraven]

That's what I was suggesting as well. Fab some patch panels and weld them in a piece ar a time so the rest holds it together while a short piece is cut out. Possibly do some removable bracing before you start that. Get the doors to fit before you brace and cut. Scribe a line above and below for reference to the center line. When welding do short bursts and allow to cool so it doesnt warp.

[mr48chev]

I've got what you need here at my place but you would have to have a buddy with a truck that comes down to the Yakima Valley of Washington state to haul it back for you.

That is a real straight and solid back panel of a 53 truck that is cut off though the middle of the rear window and that I am going to cut the cab though the floor somewhere to use the front half for my stretch cab's cowl. My buddy cut the roof off probably 30 years ago and I have had this thing stashed away ever since. There is one dent in the belt line on the passenger side that has to be fixed. You could use as little or as much of it as you wanted to.

That meaning to me that the best way to fix it is find the back section of of a donor cab that is in real good shape that you can use as much or as little of it as you are comfortable with. Then cut the outer sheet metal though the rear window just as if you were chopping the truck and cut and fit and weld back.

This is the 51 cab that I am using for the back half of my build with cut line. This back half gets welded to the front half of the blue 53 cab. The actual simplest way if you found a real nice back section of a cab is cut the cab through the window and cut across the floor and replace the whole back section. That would keep the finish metal work to a minimum especially if you popped the inside cab panel out before you cut the roof.

[dsraven]

great idea. short weld on the outside area that way. brace the cab well and get some good dimensions before cutting and BOOM, done. time spent driving is better than time spent forming patches, tacking till you're blue in the face and then banging the metal back where it needs to be after. maybe just truck it to the Coutts/Sweetgrass border crossing storage and grab it from there or have it shipped all the way. where in Alberta are you located, roughly?

I'd make him fill the gas filler hole first before I dealt on ANY really good looking, cheap, rust free parts that are gonna save you time and money and make for a more solid build. haha.

[mr48chev]

I actually bought the truck (1-1/2 ton) that that cab was on just to get the back half of that cab and the roof. The cowl has some rust in it that I don't want to deal with but can save someone else's cab. Well maybe but the the best part of the front is the firewall.

This is a photo I took when I bought it. I got it and the green one for 100.00 for the pair in January 2012 just days before scrap metal went sky high.


The back of the frame had probably between 500 and 1000 lbs of metal welded to it to mount various tanks and pumps over the years.

[smoknbarrels]

Yea, been racking my brain how to fix this.. I was thinking of bracing everything, then cutting the whole strip out , then weld in a curve part.. but that’s a lot of fooling around..
And with such flat metal above and below the seem, it could get warped real easy.. May just be better to find a better cab..

[mr48chev]

I'd say that you need to evaluate the condition of the whole cab and decide If the whole thing is going to require far more work (just the cab shell) than hunting down a good cab that requires far less work. That may also depend on what is available cab wise within a reasonable distance. The further you are from scrap yards and the picker/flipper brigade the better chance you might have of picking up and old grain truck for the cab. I say old grain truck because in a lot of areas where you find wheat or other grain being grown or other row craps being harvested those trucks only got used a few months out of the year and a lot of them got parked when they became obsolete or when it became harder to get engine parts easily.

Still you may be able to skin the back of the cab without cutting into the actual structure that much with some diligent cutting and fitting.

When I did the suicide doors on my 48 i took the bottom part of the frontdoor posts from another cab and changed them side to side to use as rear door posts with hinges by carefully cutting out the spot welds when I cut the old door posts out. It would take some carefull trimming around the belt line area but it could be done. Just cutting through the windows and floor seems to be simpler in the long run though and you can cut at the seam right next to the door post and not have to cut straight down though the rockers.

[mr48chev]

I went out and looked and the back side of the blue 53 cab may not be as good as it used to be with some rust spots showing on the seam.

The last shot shows the orange 51 cab back to back on the trailer with the 49 cab that is really in rough shape.

[smoknbarrels]

Not bad, the one I was looking at a person could put a finger through in several spots..
I think I’m gonna move onto a better cab, I think that repair job is above my pay grade!

[mr48chev]

I'd have to say, spend a bit more money and buy the best cab you can get your hands on that you can afford. That green cab in the bottom photo in post 13 was given to me over 30 years ago and I have packed it around ever since. It was pretty bad then and all I saved it for are the firewall and the roof. I was going to use the cowl on my new build for a long time but it just needs too much rust repair to deal with for me.