• Welcome to ClassicBroncos! - You are currently viewing the forums as a GUEST. To take advantage of all the site features, please take a moment to register. It's fast, simple and absolutely free. So please join our community today!
    If you have problems registering or can't log into your account, please contact Admin.

Body Repair: Replacing Floor boards

Grunt1058

Bronco Guru
Joined
Sep 8, 2003
Messages
2,363
Loc.
Land of Entrapment
One of the most common places for rust to reside in your Early Bronco is in the seams of the floorboards. The most recommended way to correct this problem is to cut out the infected floorboard and to install new sheetmetal. Dennis Carpenter sells factory ribbed replacement floorboards, or you could purchase flat sheetmetal replacement boards for about 1/2 the cost. All in all, it's a fairly inexpensive fix.

Prep: Remove everything that will be in your way when working on your floorboard. I removed my entire gas and brake assembly as well as my drivers seat. Then, make sure you don't have any wires or fuel lines under the infected floorboard to be cut out.

Once you get everything out of your way, you can use a 4.5" angle grinder with a wire wheel to clean up the infected floorboard as much as possible. Paint thinner / Aircraft remover etc. works to get the paint off. Then, using a punch and drill, drill out the spot welds on the old floorboards. Die grinder may be helpful for some spot welds since they are not all uniform in size, shape and placement. Also, a sawzall might come in handy to trim down the size of the project you are still working on.

Once you get the old floorboard out, clean up what is left of the sheetmetal. Including your support bracket beneath the floorboard. Now is a good time to treat this now exposed area with rust protecting paint. I used a weld through primer on my application. It is also good idea to paint the underside of the new sheetmetal at this time. Then, test fit the new floorboard. I used a sharpie (permanent marker) to draw lines everywhere my new floorboard would overlap with the old sheetmetal. Then, mark a dot every 2 to 3 inches along the floorboard where you want to drill your spot welding holes. I found it most useful to drill the body mount hole first and actually bolt the thing in place before starting your welds through the rest of the process. Once you have the new floorboard in place, fill the seams with a good quality body filler and let it dry. Then, prep and paint the new floorboard to match your Bronco's color.

If you have anything to add/remove or modify to this, please contact me and I will get it updated.

Pics are in the near future (when I find the ones I took)
 
Last edited:

broncosbybart

Bronco Guru
Joined
Mar 13, 2002
Messages
2,644
alternative

I've worked on a few that were so rusted the spot welds were either hard to find or couldn't be found. I've found it easiest to take a 4" grinder and grind through the floorpan- but not through the cross member. Usually the only drilling of the spot welds that I do is for the inner rocker panels (right near where the door weatherstrip goes) and along the kick panels. I hate drilling spot welds. I find grinding to be more fun- but I always wear ear and eye protection and a particle mask.. An added bonus to using the grinder is that when you install the floors, you don't need to worry about trying to re-fill the holes you drilled in the crossmember- if you are really picky like I am. It is a lot harder to weld upside down, laying under the truck. I think I still have a scar or two on my neck from doing it that way.. I cut the floors out with a whiz wheel- but it uses a lot of air to do that.
 

bigbri69

Sr. Member
Joined
Oct 7, 2007
Messages
421
Loc.
tomsriver
what if you realy have nothing left of the floor.my floor is rotted up to the kick panel and tunnel cover.dose the new floor panel have a lip or do you just butt it up and weld the seam?thanks
 

broncosbybart

Bronco Guru
Joined
Mar 13, 2002
Messages
2,644
i'm going to go ahead and guess that you're probably going to need kick panels/inner rockers/outer rockers/ and probably door and striker posts also- kind of a big job if you've never done much metalwork.

depending on the floor pan that you purchase, it should have adequate tabs that you can use to weld to the orig floor. i'd recommend the 'oem' kind that can be found at the major distributors. another word of warning is that there is one crossmember found under the driver's side floor pan, and 2 on the passenger's side. be sure you don't cut through them when you remove the floors. if they are in bad shape, you'll need to replace them, too. then you really get into alignment issues if you don't put it together properly. feel free to pm me if you'd like more info.
 

muskrat

Bronco Guru
Joined
Aug 21, 2008
Messages
1,466
welding floor boards

Hello, thanks for your post. Question. Never did body work before and I'd like to redo the floor boards and some areas in the back this winter. Is is OK to "overlap" the new metal over old, as long as the old metal has been cut free of rust? I was invisioning a "flush" install, where the new metal would be fit flush with the old the welding in place. Honestly, as I envisioned this, it started to sound like it would be very difficult. Please let me know.

Also, is this a job for a wire fed mig welder?

Thanks,

Dave
 

Redneck Rich

New Member
Joined
Jun 13, 2009
Messages
6
I used sheet metal screws to hold and secure the sheet metal in place. the
sheet metal screws drill the perfect hole for spot welding. you screw where
needed , every three inches or so. remove the screw and weld. with all the
screws in place it will keep the metal from warping. go slow ,weld let cool. the screws are 3/8" . you can get them in various lengths. with a longer
screw you can suck in a bib gap. you also need a screw gun with a 3/8"
chuck. redneck rich
 

KOBALTBLUE

Jr. Member
Joined
Dec 15, 2012
Messages
117
Loc.
Daphne,Al
""Once you have the new floorboard in place, fill the seams with a good quality body filler and let it dry. Then, prep and paint the new floorboard to match your Bronco's color.""

Never use body filler for seams you use SEAM SEALER! Its water proof body filler is not.
 

wepuckett

Contributor
Sr. Member
Joined
Apr 28, 2014
Messages
721
I have a question on floor pans, do you need to replace them before you pull the body off the vehicle or can you pull the tub off and replace them on the ground or on a bench or roisserie? Trying to figure if I can pull the whole body off then do all the work and rust repair to it or need to do some of it while still mounted on the frame.
 

prouddadofthree

New Member
Joined
Oct 26, 2014
Messages
19
Loc.
Piney Flats, TN
I have a question on floor pans, do you need to replace them before you pull the body off the vehicle or can you pull the tub off and replace them on the ground or on a bench or roisserie? Trying to figure if I can pull the whole body off then do all the work and rust repair to it or need to do some of it while still mounted on the frame.

What did you end up doing?
 

JAFO

Bronco Guru
Joined
Dec 3, 2007
Messages
1,556
Loc.
Beaverdam
Based on my experience, I left the body on the frame as I replaced each rusted section (floors, door posts, etc). I ended up suspending the front of the truck from an I-beam using I-beam hangers and threaded rod attached to some make shift brackets attached to the hood hinge holes. This allowed me to raise or lower the front of the body while I got the front door posts replaced and lined up. I also left the hard top in place as it helped keep things lined up. I think if you remove the body from the frame, unless you have welded in tons of support rods all over, the body is going to shift horribly and you'll never get it lined up. Also, lots and lots of vice grips and self tapping screws will hold things as you get everything aligned before you try welding stuff. Just my two cents.
 

RVZIO

Full Member
Joined
May 9, 2019
Messages
163
Loc.
New Smyrna Beach
I will be getting ready to do my 67 U14 that I picked up. I have been restoring C3 corvettes and at 71 decided that I would like to do another type vehicle. I chose the Bronco for it's openness if you will. Anyway I have my shop on my property and am looking forward to the restore. I always have tons of questions. My shop has a nice DIY paint booth and lift. I plan to practice up on my welding skills with my MillerMatic 175. I will get gas for it and test and test. I was going to pull the body but it does make sense to do as much as I can with the body on in order to keep it straight. Great info here for sure!
I am old school at 71 , start work at 8am break at 10 lunch at 12 2pm break knock off at 4/5. give me a purpose to get up.
RVZIO
 

Attachments

  • 20181122_094649 (1).jpg
    20181122_094649 (1).jpg
    142.5 KB · Views: 84
  • 20190515_184651.jpg
    20190515_184651.jpg
    126.2 KB · Views: 85
  • 20190515_184643.jpg
    20190515_184643.jpg
    144.5 KB · Views: 77
  • 20190515_184701.jpg
    20190515_184701.jpg
    69.2 KB · Views: 80
  • 20190515_184822.jpg
    20190515_184822.jpg
    128.2 KB · Views: 78
  • 20190515_184729.jpg
    20190515_184729.jpg
    102.9 KB · Views: 91
Top