Installing New Floor & Rockers


Bigger Hammer
Feb 28, 2011
S. Jersey
Willys Model
Willys Year:
Ok, I'm new to this replacement thing, first time cutting out old floor & rockers. It seems cut and dry, but I thought I'd ask before I cut and maybe screw up (my M.O.). I drill out the old spot welds remove the old floor, cut the rocker even with the door posts? clean and mig in new one? Is it that easy? m I missing something or a lot of somethings. By the way I have no sheet metal experience or mig welding. The machine I chose for mig welding is a Hobart 140. From what I understand it will do sheet metal easily. I think what bothers me most is screwing my project up to the point of no return.
Installing New Floor & Rockers

Sounds like you pretty much have it. Welding in itself is not that tough, the hardest part of sheetmetal work is getting everything measured right and fit correctly. Keep in mind that you really need the metal clean that you are welding the new stuff too, so, as is almost always the case, you may be replacing more metal than you are originally planning. Fortunately, if any of your floor bracing is bad, many of those pieces are available aftermarket to make it much easier to piece back together.

Don't worry too much about making it irreparable, because a good fabricator can fix almost anything. And really, if the floors are bad enough right now to need replacement, then how much worse could you really make it.

Good luck. Post pics of your project if you can.

Couple points.

I had little welding experience till this project. Also used a Hobart 140 for awhile too.
Now on another machine cuz the deal price was great.
As for sheet metal experience NONE. Now I have enough to get me in trouble......

The plan for getting something like floors and rockers done is never too cut and dry if you ask me.

Trial and error is part of life and learning how to do something. You did ask a good question though.

Good luck.

Thanks for the encouragement guys, I do have a junk parts truck (its in 2 pieces, frame rotted through), so I might practice on that first. Yes clean metal is a must from what I've read, so that will be my starting point when welding. My thought here is wire wheel the parts till they look like new. I do have a question, under the front cowl & cab where the fender bolts up are some mounts with nuts afixed to them that the fender bolts to, I broke every bolt turning it out, do I have to drill out and tap them? They look like they could be replaced by chiseling up the edges. The other is if you replace the lower part of the cowling, can I buy the pieces the fenders bolt to or must I make them? Wow so many questions. Wish I were younger, I'd know everything, oh well, thanks guys for your help. Oh I'd post photos but can get the hang of it.
If you mean the front cab mounts,they are a bolt and nut.So if you break or cut them you can drift out the stub.
Before cutting and welding it's a good idea to check door fit.On a rusty cab things might sag and get out of alignment.Sometimes you have to temporarly weld braces on the door opening to hold it in alignment while cutting and welding.If the doors are left on the cab you can close tem from time to time to check the fit.
About the cab mounts;it's usually better to have the body or cab on the frame with mounts tightened before doing a lot of patch work.This assumes the frame and cab mounts are ok. Work around the patch with stitch welds.The patch doesn't need to have perfect welds,a few spots can be skipped,it ain't a show truck? :D
Do not get in a hurry or you'll be chasing your tail on door fitment issues that are caused by the metal expanding and contracting.

Measure 10 times cut once. Take lots of pictures at lots of diff angles. Even if you can't post them here you can have them to look back and see what's supposed to be where. Try measure from points rearward of where you're working to the end of where you're working as well as a point just forward and make sure it's square when you start and when you're done. Write those #'s down.

Get a good weldable primer.
Remember cardboard is your friend.
Template of you're patch (if there not enough metal left of the cut out, or its warped and dented to badly) will save a lot of $$$$ in wasted metal. I have been shock at people eyeballing things, measure twice cut it a littel bit larger then you need and trim it to fit like a glove, then weld.

Don't fear the welder! If you have ugly welds well that's why we have grinders! just take your time and don't over heat the sheet metal is the only fear I ever have with this stuff, a wet rag helps to keep the metal cooled down.

Practicing on some junk metal is a great idea even if you change welders let alone learning. Play aroud have some fun you'll get the hang of it!
Hi Rich, When I did mine I learned to spot weld every thing in place 1st. I welded a 1/2 inch spot then skipped 3 or 4 inches and did another 1/2 inch spot but first I spot welded a place or two on each side of the new floor to hold it in place while I finished the spots. Then I went back and welded each gap about an inch and let it cool then continue welding an inch or so in each gap until you get it completed.Then I used my angle grinder to smooth it all down. Turn your welder down so you won't burn holes in the floor but if you do you can spot weld the holes to fill them in and grind them down. I had lots of holes the prev owner drilled to bolt all kinds of accessories to the sheet medal body,he had gas cans brackets on both sides, off road lights on top, back up lights,license tag bracket and a luggage rack on top.All that stuff is gone to the junk and the holes welded and ground down with a small amount of body putty to slick it over, then painted with several coats of undercoat and finally two coats of finish paint. good luck and above all take your time as this is a labor of love and a source of pride OH by the way I posted pictures on the gallery
Fred Potter PS you can click on the link at the left where it shows images
Hi everyone

I agree with everything everyone has said before me. My only word for the wise is after you cut all the rusted junk out climb underneath and scrap all the oil and crude before you weld all the new metal back in. I remember as a kid my dad was redoing a 1968 Mercedes Benz and he was working on the firewall and something caught fire underneath and he about lost the whole car. My old Willys truck has plenty of grease and grime so beware before you weld clean and scrape, old oil is just as flammable as the new stuff is.
Good luck with you project....remember it is only a Jeep.
I'm in about the same place as you. I plan to use a grinder and sawzall to remove the old stuff before I cut patterns. A little unsure of when/where to weld in bracing to keep everything square, but I plan to build a rolling platform out of angle iron onto which I will set the body. Hopefully I can make that good and square.
I've read a good bit on welding sites, and practiced on scrap. One thing I got hammered into my head is to be SURE the metal is clean and shiny. Wire wheel might not do a good enough job. Might need a grinder with less aggressive grit to get the old rust completely gone. And dont be tempted to use brake Kleen spray on the metal to get rid of grease or oil. Evidently when heated in the welding process it creates Phosgene gas or something that is DEADLY when inhaled. Get a fan to exhaust your workspace. :shock:
The idea of making a cardboard pattern is good too.
Thanks guys, the cardboard idea is great, I'll remember that! I'm keeping the cab on frame only due to the fact that I haven't a garage to work in or anyone to help lift the cab off, which isn't a bad thing I think cause it should help keep the cab square. I also have read a bit about mig welding, and as you I have learned that keeping the metal clean is the key to helping make a good long lasting weld. After I finish the floor (geez that word makes me paranoid, I'll just double my Prozac that day) I'll try to unbolt and block the cab up a bit and clean up the frame. What grit is a good metal grinder wheel? ----Semper Paratus----
Hello Rich. When I fixed the floor in my 57 Pickup, I decided to patch my holes with new steel instead of buying a whole new floor. For one reason, I didn't want to wait for the new floor to get here. All the points previously made on this subject are all good. I'm adding my two cents worth just as another example. After I was done, the floor was fixed and very solid. The fix is going to be covered up, is why I didn't grind the welds super flat, plus I wanted more material at the fix. Here's the link in my build log of this process. Good luck! ... up/page-17
Several points,
Regular grinding wheels work good for fast material removal but leave a rough finish. Fairly cheap.
Flap wheels (sandpaper with plastic backing) are a little less agressive but leave a nicer polished finish. Higher cost, do hold up pretty well if you avoid hot metal or sharp edges.
Zip discs (1.8" thick wheel) are very efficient for cutting thin metals. Hold up pretty good if you don't force them into the cut too fast. Mediun price.

If you do not have a auto shading hood seriously consider getting one. You do not need a high dollar one, new ones start around $70.00 and they work fine for most everything you will run into. Without the auto shade you will be more likely to line up and start your weld before flipping down the lens as it takes a lot of practice to hold the welder steady as you drop the lens. It does not take but a few milliseconds of direct arc light to cause a flash burn in your eyes, and several hours later they will hurt and feel like there is sand in them. I have known several people who have gone to the ER for flash burns and one visit to the ER makes the cost of an auto hood look cheap.

If you do not have gas for your welder then the flux core wire will spatter quite a bit needing more clean up. Flux core usually burns hotter than solid wire. Inside the wire cover of the welder should be a chart for wire speeds and heat settings by metal thickness, they will help you get set up.

As to the broken off studs for the fender mounts it may be possible to soak them in your favorite penatrating oil for a few days keeping them wet and then welding a nut over the part of the stud that is sticking out. If they are not sticking out then you may need to drill and repair.
Thanks again everyone for the much needed help. The massive amount of work this truck needs is a daunting task to say the least. I must be losing my nerve I guess, lol. I'm starting with the cab, reason being is I think it needs the most work & if I must in the future lift it off it will be stable.
I'm practice welding now with .30 flux core, my feeling is, being good with flux core will make my welding with gas better and easier, I hope. As for working in smaller pieces of floor, I think replacing the floor in one whole lager piece will generate less heat wrapage overall. Today I was looking (raining here in NJ) around the windshield and cab for small leaks and marking them with marker for repair. Looking at the windshield where the glass has discolored it leaks so I lifted the gasket and lightly poked the lip where the gasket sits, its all rotted. Has anyone ever repaired this lip. It appears to need a lot of metal fabricating on the outside cowl to to make the necessary bends.
I did buy the auto darkening welding helmet, I figured that will give me the best results. So I seem all prepared I think. Once I learn to post photos here, I'd like to share my progress.
After thought, how about using electric metal shears for cutting out rotted steel, they can make straight cuts and cut clean?----Semper Paratus---
I've never had good luck with shears on tightly curved metal. A 4 1/2" grinder with a cut off zip disc is pretty efficient in most areas.

If you can get behind the areas where you need to patch holes you can put something like a peice of copper back there to help control your heat. Eastwood has some for flat areas. They have a handheld for curves They have a little one for hole patching. These are just some ideas, if you can come up with some copper elsewhere it works good as a heat sink to lessen the warping and the weld doesn't stick to it.

Any place there is a hole it will be very thin around it and will melt away. short burst and let it cool a few seconds. It is frustrating and slow but good welding practice.
Cnsay---Thanks for the great copper tip, now I'm off to the Eastwood site to order.----Semper Paratus---
Ok, it's been awhile, how about some pic's on your progress? And remember a poor weld can always be've done it many a times.
Good Luck Rich on your project, and thanks for asking all those good questions. Some were on my own list. Great advise and information from the experienced members here. Thanks to all.
When I do this type of work, I run into a couple of challenges. The biggest challenge is attaching the new sheet metal to the old sheet metal. Sometimes it makes ugly welds, or makes them inconsistent. There's really nothing you can do about it, just have a back up plan, or plan to add more steel and get ready to grind some more.

Also, be sure to run no more than 1/4" beads. I was dumb enough to try slightly longer beads and warped my first floor pan a few years ago. I had to start over because I couldn't shrink it enough to go flat. Be careful and you won't have to re-do stuff like me!
Tomorrow when I go outside I'll take a few photos, though I think you'll be disappointed, Its been rainy here in NJ almost every day and then the good days are overcast with the looks of rain. No garage here to work in. I've procrastinated because of it to, though I've used some of my time wisely. I removed the floor slowly in pieces (slow learner here) then I cut my one new piece floor board into 3 pieces for easier installation I think, not sure I like this approach, then removed the rocker in 1 piece, another brace in 1 piece and took pictures of each before removal so I knew how to replace them and where to place my welds. Each new piece was then cleaned and primed and test fit. I've made several new floor supports from my junk trucks old seat back supports that are bolted to the cab's inside back. Great u shape and has a continues flange for welding.
I'm new to this whole thing so I made a plan of teaching myself to gain the experience I need to complete this project. I also like sharing my experiences in hopes of helping others, as they have with me. I also like coming here and chewin the fat with you guys. If I were smart I'd write a book with all the info. found with the members.