Announcement

Collapse
No announcement yet.

Floor pan replacement question

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Floor pan replacement question

    So I'm finally getting around to welding in new floor pans in the f150 (I've had the pans for about 2 years).

    I have cut out the section of really bad floor. Here:



    The purple line indicates where the new pan ends.

    3 options:
    Do I cut more of the floor out to have new pans?
    Do I cut the pan down to where it only covers and inch more than the hole all the way around?
    Or do I weld it in and have huge overlap for strength (grinding down the rust ans weld-thru primering, of course.

    Please advise. Keep in mind this is a work beater, not a show car. Funtion over form.

    Thanks in advance.


  • #2
    Re: Floor pan replacement question

    And, yes, once I cut out the pans I noticed my crossmember has been held on by only one bolt on each side.
    Thanks, PO.

    Comment


    • #3
      Re: Floor pan replacement question

      Rule of thumb is to replace no more metal than you have to. Several reasons for this...main one being that repop parts usually aren't made right, so you have less work to do making it fit that way.

      Or see where it would be most convenient to weld, or where it would hide the weld better.


      Just make sure to cut it a little ways past the rust, you want to get rid of all the rust!

      edit: I'd probably go forward past the rust an inch, no more. Up the sides maybe an inch. Overlap enough to make the weld easy and strong, no more.

      My fabulous web page

      "If it don't go, chrome it!" --Stroker McGurk

      Comment


      • #4
        Re: Floor pan replacement question

        If you want the practice, it's best to butt weld. A lap is OK and slightly stronger but there's a tendency for the panel to begin rusting at the lap as it will hold water and it's hard to get paint or sealer into the lap. Once the panel is fit for the butt and tacked into place it really isn't any tougher to butt weld. Remember to move around the weld to minimize warpage (floors are a great place to learn). I agree with Jim - make sure you remove all the rust but don't go much bigger. Get everything VERY clean on both sides before welding - it's a real PITA otherwise.

        Dan

        Comment


        • #5
          Re: Floor pan replacement question

          What Dan said... my 2 cents - make sure you can clean the back of where you're going to weld - many times that is the highest point you can cut..... tranny tunnels are notorious for having caked on grease; firewalls - for sound deadener... both of which make entertaining fires.
          Doing it all wrong since 1966

          Comment


          • #6
            Re: Floor pan replacement question

            I would lap it, but I live in AZ....

            My fabulous web page

            "If it don't go, chrome it!" --Stroker McGurk

            Comment


            • #7
              Re: Floor pan replacement question

              work beater go find some street signs LOL LOL
              no really get all the rust if you can . butt weld if you can . and if you have trouble with gaps or blowing holes wedge a peice of 1/4 inch aluminum behind it weld against it then pry off no holes and gaps fill easy been there done that it works

              Comment


              • #8
                Re: Floor pan replacement question

                Thanks for all the help, guys.

                I think I'm going to lap it; like Squirrel said, it's stronger and I do live in Texas...the last time I saw water was in 08 I think. Maybe on a better car down the line I will practice my butt welds.

                I don't really want to cut out any more of the floor, esp. up higher in the front. The floor and firewall meet at the edge of my cut and I like having the strength. I do plan on grinding down all the rust you see there, so hopefully that wont be a problem. Then I will prime it so it will stay clean.

                Here's my new plan : I will cut the new pan down more to just cover the hole. Then I will weld it from above and below. Does that sound like a solid solution?

                Comment


                • #9
                  Re: Floor pan replacement question

                  Drill alignment holes and screw it in place with sheatmetal screws or pop rivets. Get it tacked in place with the screws still in place so it won't move on you then plug weld the screw holes solid before welding the perimeter of the lap joint. Weld around 0.5in at a time on opposite sides of the panel and go slow.
                  Central TEXAS Sleeper
                  USAF Physicist

                  ROA# 9790

                  Comment


                  • #10
                    Re: Floor pan replacement question

                    CTX has the plan. In Texas the laps should be fine. Still, seal and paint as best as you can. Great Luck!

                    Dan

                    Comment


                    • #11
                      Re: Floor pan replacement question

                      Yes, weld it top and bottom. Also, use the weld through primer so that the overlap doesn't rust from the inside. If you are going to undercoat the fix, use seam sealer and then paint it first. You'll have a good fix that lasts forever. For the record, you couldn't have chosen an easier vehicle to do your first floors. Been there, done that. Way easier than most.
                      "A cross thread is better than a lock washer." Earl Lanning...My Grandpa

                      Comment


                      • #12
                        Re: Floor pan replacement question

                        Its very easy to pull the cab, do it it will make it butter to do.
                        2007 SBN/A Drag Week Winner & First only SBN/A Car in the 9's Till 2012
                        First to run in the .90s .80s and .70's in SBN/A
                        2012 SSBN/A Drag Week Winner First in the 9.60's/ 9.67 @ 139 1.42 60'
                        2013 SSBN/A Drag Week, Lets quit sand bagging, and let it rip!

                        Comment


                        • #13
                          Re: Floor pan replacement question

                          I just started welding, and my first project was patching some holes in the floor of my '62 Suburban. I had to fab the pieces from flat sheet... These were small areas, and I was able to duplicate the contours with a HF bead roller and sheetmetal brake. I butt-welded them, strictly for the practice. It was extra work, but I learned A LOT.

                          Next up is replacing the foot well areas like you're doing, only mine goes up into the toe-board area. There's a seam there on the original panels, but the replacement doesn't have a seam, it just goes over both pieces. I'll cut the replacement, bend flanges on the end and recreate the originals. It's excellent practice, on a vehicle that "good enough" is just fine.

                          -Brad

                          Comment


                          • #14
                            Re: Floor pan replacement question

                            Yeah, I'm still not sure how much to cut out of the old floor. If you'll notice the engine side of my square hole, the metal is 2 pieces. The lower piece is actually fine, but the upper one that travels up to the firewall still needs to have some rust cut out. So I guess I will just trim the top metal but not the bottom, then weld the lower peice to the bottom of the new floor pan from underneath.

                            If that even remotely makes sense.

                            Here's a pic with the new pans set in:

                            Comment

                            Working...
                            X