Thought I'd start a thread showing the repair of my cab. Truck is a 1980 F150 4X4 with 300 L6 and a T18. It was, anyway, before I took it all apart! I knew the floor pan o the drivers side needed to be replaced but didn't know how bad the rest of the rust was until I gutted the cab. Oh well, time to learn basic welding.

Here it is on a dolly I built for it from 2x10 boards and some roller wheels.


Here's a shot through the back window of the floor. The driver's side is really bad. Passenger doesn't seem terrible but I'll repair it anyways because there are small holes.


Here's some more closeups of the drivers side. Looks like i'll need floor pans, rockers, and cab corners (the full works!). Not sure how much the aftermarket LMC/BG pre-made metal covers... I'm assuming i'll need to form some stuff by hand to weld in.








Here's the passenger side. Not as bad but still needs replacing. It looks like there's a burn or heat mark... I'm guessing the exhaust system wasn't properly hooked up and caused it to turn color? I'm debating replacing that spot or keeping it...




This is the worst spot on the front of the cab, near an AC hole.


I'm going to attempt to repair all this... problem is, I've never touched a welder in my life. Oh well! It's supposed to be a work truck so I don't care if it doesn't look that great.

So now I need to get a list of all the tools I'm going to need. So far I need to get a MIG welder, all the floorpans/corners, a smaller cut-off tool (already have an angle grinder), some clamps, etc. There won't be much progress while I collect all this stuff and come up with a game plan.

 

I would seriously look at replacing the entire cab with one from a junkyard, mine was only $75 (bare, stripped of everything). 1980-86 are a direct fit, 87-96 (and 97 F250) will bolt on but they have rounded wheel openings instead of the square ones.

 

I want to say that welding is easy, but I already know how to do it. I have a nice little Lincoln welder with gas, so it works very nicely on sheet metal. I know that lots of guys weld with flux core wire (gasless) but I have no experience with it myself. You can buy zip-cut disks to fit your angle grinder, that's what I use. All of the panels are available, mostly...but you'll have to cut your own pieces to fix spots like the holes in the firewall behind the heat/AC box. Be careful cutting the cab up...they will deform if you cut too many of the rigid parts out, so if you're going to do that make sure you weld some support braces in it first. However...all that being said, it will still be cheaper (and far easier) to buy a southern cab that needs only minimal work (usually just cab corners, and maybe some small holes in the floor). But, if you have time and want to weld, then have at it...people have fixed worse cabs.

I'm in the process of rebuilding a rusty 1980 F150 4x4 that for all intents and purposes should have been scrapped. The frame was bad in it so I swapped in a later year frame (which was also rusty, but less rusty...lol). I haven't even gotten to the cab yet, but it is similar to yours, but not quite as bad. So I understand what you're doing, but you have your work cut out for you.

 

That burnt spot looks like the catalytic convertor got hot. That is very common when the engine doesn't run right (too rich) the cat can turn cherry red. And then the heat shield is probably long gone that goes over top the cat, so then it gets the floorboard hot and melts the carpet.

 

If lucky it melts some catch fire 🔥
For the panels get them from Tabco.com won't go wrong.
Dave ----

 

I do admire your ambition and I like your dolley but I also would recommend at least checking around for another cab. Especially with no welding experience. This coming from someone who has done body work on these old trucks all my adult life. It may be that you can't find one in your area and have to work with what you have but then again you might and save a lot of time and money in the long run. No disrespect intended, Just a thought.
Might give "car-part.com" a try to search salvage yards in your area.
Is the rest of the truck in the same shape as the cab??

 

I've thought about it. Problem is there's very few cabs within a few hours drive, and even then, they probably have this Michigan rust that I'd have to fix anyways. Another thing is I don't have a truck (lol...) to move another cab to my garage. But $75 for a bare cab is a deal that I'd take if I could figure it out.

All good advice, thanks. I think I'm gonna go with a MIG and use the gas, and try and replace only one panel or portions of one at a time so don't need to weld supports in. I'll have to find your build thread. I basically did the same thing as you; my frame was shot so I had Dave hook me up with a much better one. It's all good now! I'm actually looking forward to welding... but maybe that'll change after the first go.

I wouldn't doubt it at all, this truck was in super bad shape to begin with. The original exhaust was cut right after the inlet and held up by a chain... so maybe after the PO noticed the heat they just cut the problem right out!

Thanks Dave, haven't heard of Tabco before. I took a look at some of your old pics. Gives me hope and some kind of approach to this problem.

Thanks, no disrespect taken because swapping for a different cab would be a money saver for sure. Like you said though, there's not much around here and the ones that are probably have rust, too. Unless someone's got a lead on a clean cab, I think welding is what I'm gonna have to do. That's ok, been wanting to learn anyways. Plus, even if I mess it up, no one will see it under the carpet right? lol

Well after the suggestions I did look for an hour or so for a different cab. There's lots of things I don't really want to mess with, like the logistics of getting it here, getting rid of the old cab, the VIN, etc. Looks like welding is still in the plan for now..

 

If you don't get a title with the replacement cab, then you really can't use it anyway if you did find one.

 

Well, I got some of the tools needed for this job. Bought an off-brand MIG welder and Ar/Co2 gas mix, clamps, bodywork hammer/dollies, magnets, welding gloves, helmet, etc. Also took Dave's advice and went with Tabco for the replacement sheet metal. The look pretty sturdy. I bought everything I could for the lefthand side of the cab. Cleaned the garage and made room for this little mini-project.



So how do I even start this? Looking at some other threads, I think it's best to do the cab mount/floor pan first at the same time. Basically cut the top of cab mount off, put in the top of the floor pan, and kind of stitch it together simultaneously. First though, it looks like I need to fix the "cab bracing" or whatever it's called under the cab first. In the below pics, you can see the cab mount is welded to this long structural part that also held on the fender I think?




Here's from the front of the vehicle. The "cross brace" supports the cab mount and then twists to form the flat face which the cab mount bolt goes through.



The cross brace continues past the cab mount and turns into a mount that supports the fender if I remember right.


Also, what is the part that goes over the cab mount hole on the floor pan? I don't remember seeing that anywhere in LMC truck, etc.





So I guess my questions are:
- The "cross brace" seems needed to get the cab mount in place. Is a good plan to repair/weld a new "cross brace" piece, including the part that mounts to the fender, then tackle the cab mount/floor pan simultaneously?
- How or what do I do to get the removable cover for the cab mount bolt that I don't get with the floor pan?

Any tips or hints are appreciated too. I think the plan is to flip the cab on its side so that I can access the bottom and repair the cross brace first. Or at least jack the left side of the cab up enough to have some room to work.

 

Obviously you are going to need some extra pieces of metal. To make a new brace piece and you can also make your own cover for the body bolt access.

 

If I were doing this, I would not try to re-make that rather complex end of the brace. I would make the simpler "S" part of the brace using a piece of angle and a hammer to bend it, and just leave it a little long and lap it over the piece in the picture below. You may also be able to get some thin angle iron and stich it together to make a new brace.

 

I see more than likely you have the door off the cab? I would be careful when you do the rocker. It would be nice to cut the rocker out, put the new one in using a few screws, and then check the door gap before welding the rocker in permanently.

 

Ah, so it's just a simple cover. So I can cut out the hole in the floor pan and make a makeshift cover for it using scrap metal. No problem there (hopefully).

Yeah, I'll probably strengthen the brace as much as I can and try to keep that complicated shape that holds a fender bolt.

As for the doors, yes they are off. I was thinking of getting metal bars to weld in and keep the shape of the cab.... but decided if I do things piecemeal the squareness of the cab won't shift too much. When I get to the rocker, I plan to put the door back on/off many times to make sure the doors still fit properly. If I get new doors from LMC or bronco graveyard, will they be a similar fit? Just hopeful that if I go through all the trouble to make sure the original doors fit, that if I get new ones I won't have a problem.

 

My front cab mounts and that support brace were not bad on my truck so did not need to touch them.
Because of that I drilled out the spot welds with a sport weld drill bit so I was able to remove the floor part.

On the floor I put the new part over the old one and marked around the outside so I knew how much the new floor would cover.
I then trimmed the old floor 1" or a little more inside of that as I did an over lap of the new over the old floor.
I punched holes about 1" apart all the way around the new floor pan and did plug welds thru them.
Because of the drilled out spot welds on the cab mount & brace I plug welded thru them from the under side.

For you because of the bad mount & floor on the driver side and not able to get the parts in the right place before welding I think I would replace the floor like I side above, the rocker, door posts and cab corner so it is all held in place. Then move the cab to the frame so the mount can be in the right place, tack it in place then remove to finish welding and that brace.

The other side being the floor is not to bad, is the cab mount needing replacing? You could do it like I did and drill out the spot welds to that brace & mount and cut the floor out for replacement.
Here is a link to pictures on my site as they may help you. 1980 Ford F100

On the cab mounting bolt access I dont know if anyone makes them?
I would check the junk yards on newer trucks to see what they have and if they might be used for your truck?
If you cant find something I may have a set I just dont remember what shape they would be in as I used the best ones on my truck.
I was going to say I could not remember if mine were cut open or not but see in my pictures they were not but I did cut them open before I welded it in place.
I cant remember if I used a small air body saw or jig saw? I used the cover to drill the holes for the screws.

Oh I have a air power hole punch / flange tool to put the hold around the floor pan and other patches.
Good luck
Dave ----

 

I forgot to say before marking around the outside of the new floor pan, to fit is as best as you can because if you dont and cut the old floor out then fit the floor you could come up short and have nothing to weld to.
Dave ----