55.2-59 How to repair this area?

[BBPanel]

From the backside it looks like this is an overlap seam. Hard to determine the extent of rust above and below the hole. I'm thinking I need to cut out the entire seam and butt weld in a replacement piece. The other three similar areas look ok (no holes) but the seams are a little bulged in places and that makes me think they might have rust in them also. Anyone dealt with this before? Thanks. -Bob

Attachment 2169307 Attachment 2169308

[mr48chev]

I'm still not positive as to what we are looking at but assume that it is the panel behind the inside step of a 55-1/2 to 59.

This is where the assembly manual may come in handy to understand how that section went together to begin with.

[dsraven]

google 55-59 chevrolet factory assembly manual, pick the tri5 site, the manual is a free download. i suggest to download to your computer/device or download it to a thumb drive or whatever as you never know how long these things stay on the net. lots of good info in that manual.
if that is the seem at the front area of the step, 55-59, as it looks like, then that area has several layers due to the cab mount support, the hinge pillar support, hinge pillar lower inside panel, step panels and the front fender lower mounting bracket all coming together there. the assembly manual will show that in detail as well as where all the factory spot welds are. those parts are all available from aftermarket sources. if it is at the rear of the step then it is a lap joint but I dont remember anything else being layered there. crawl under with a screwdriver and do a little digging to see what you have. better to find the bad spots now, and repair properly, than find a rotten spot has added extra stress on another part and caused that other part to fail, bend, whatever. if the spot is at the front of the door step then that area needs to be strong because the door hinges on the pillar. if the pillar is not as it should be then the door will be really hard to get adjusted properly and that causes headaches till the pillar is fixed and strengthened.

[dsraven]

bulging on the seam usually indicates rust there.

[mr48chev]

I'd say his issue is how to carefully take it apart to be able to clean it up and do the repair work without causing unnecessary damage.

[Patrat]

This should give you a good idea of the shape of the part.

https://www.classicparts.com/1955-59...ctinfo/44-255/

[frkennyg]

I am working on the same area on my 57 Chevy truck. The unfortunate thing about that area is that the cab support is behind that A pillar/step filler. The area behind there is a pocket that collects a lot of water/mud/rust. Also in that area is the hinge pocket/cover that covers up the cab support. I am sending a pic of what the area looks like

[frkennyg]

Here is what it looks like opened up. I am putting all new metal in

[frkennyg]

Sorry I assumed it was the bottom of the door hinge side.

[dsraven]

If working with the pillar and or step it is a good idea to fit the door in the opening so it fits as good as possible, the cross brace the opening like an X, then remove the door to do the work as required. That is so the cab doesn't flex during the removal of old rusty metal or the welding in of the new parts. It would suck to do all that work and then have trouble fitting the door.

[BBPanel]

Originally Posted by frkennyg

I am working on the same area on my 57 Chevy truck. The unfortunate thing about that area is that the cab support is behind that A pillar/step filler. The area behind there is a pocket that collects a lot of water/mud/rust. Also in that area is the hinge pocket/cover that covers up the cab support. I am sending a pic of what the area looks like

Fortunately, I'm working on the rear wall of the inside step, at least for now and I don't think it will be anywhere as complicated as the front. If I have to do the front, I don't think I'd need to cutout anywhere near as much material as you have. The lap seam itself is the only area I have a potential issue with. Did you have rust beyond the lap seam?

[frkennyg]

Yes things went from looking ok to some major work. The front floor pans, left and right were very rusty and needed changing. The drivers side A pillar was damaged and is going to be replaced as well. To answer your question yes I had a lot of rust. I also am putting in new kick panels and plenums as well. In hindsight I should have looked for a different cab. To far in now to turn around. I am no expert but if I can assist you I sure will. Good luck

[dsraven]

frk, take a good look at what you have there and seriously consider the bracing as mentioned. my cab was really bad from the floor down, as lots are, so I sandblasted it. that really revealed where the thin metal was. spots that looked fine were actually quite rusty from the back side and looked like swiss cheese after the blasting. not good but it was good to know what I had before I started welding in patches. what happens to these trucks is the rain and snow comes in the grille ahead of the windshield and runs down each side inner cowl and out a very small drain hole at the bottom of the inner cowl. if the drain hole gets plugged with leaves or pine needles etc then the water can back up and run out the kick panel vents onto the floor of the cab. from there it runs down into the A pillar and step. since the A pillar also has the cab mount brackets attached to it these become compromised as things rust and get soft. the result is that the floor begins to sag under the weight of the cab so the floor is not flat anymore but instead heads downhill under the pedals. that is a sign that the cab mounts are rusted as well as the A pillar structures including the inner cowl, the vertical area at the front of the step near the hinge mount and the lower A pillar inner structures on the front side. the front fender is also mounted to the lower pillar area so it may also be ill fitting or rusted off. I really suggest to go under and do some digging to see what you have, remove the vertical cover just inside the door and look down inside the A pillar, remove the fender and check out the inner cowl panels along with that little vent hole at the bottom. then, before cutting and repairing, fit the door to the cab and cross brace the door opening and possibly even the cab side to side so you can keep things like they need to be for the doors to fit when done. my cab had badly worn hinges and I assumed that was why the doors didn't close well but instead had to be lifted to latch. actually, the cab structure around the A pillars was rotten so the door had no choice but to sag, even if the hinges would have been new. lots of guys are sheeting in the cowl vent intake grille and the kick panel vents and going with a whole new styke of heater to get rid of the water issues after repairing, that would depend on your build wants but either way it would be a good idea to at least enlarge the drain hole at the bottom of the inner cowl panels
the assembly manual is a free download from thr tri5 site and it has a lot of good info on how the factory put things together and where the spot welds are. it's a good idea to check it before you start cutting things apart.
just my thoughts, since I have been there a few times on a couple of cabs. I would post some pics of what the area looks like when taken apart but I am not at home right now.
keep posting and include some pics if you can. not here to call anybodies work or ideas down, just trying to give some ideas and help. it can be a big job and if done without forethought it can make other jobs, like fitting the doors, a lot harder than it needs to be.

[dsraven]

BB, the rear is way easier than the front. if replacing the panel, as patrat shows in his link, I suggest to mark the pillar up higher than you will cut, then get a dimension down to the floor height so everything is the same when done. also a dimension from the inner end of the step to the outside edge of the area where the new part will be. when I did mine I cut a pattern of the contour where the door seal touches so the shape would stay the same as I mocked it up. if you don't have any cleco fasteners they are pretty cheap online and they really help when doing this kind of work. they are like a removeable rivet so they hold the parts in place but allow some movement to line things up before welding. better than a magnet because they don't distort the weld as you get close. another thing to check is the angle from the floor to the step vertical part as some are not 90 degrees as you would think.