Floor pan sealing from underneath

Stock FSJ Tech Area
Post Reply
User avatar

Topic author
Posts: 21
Joined: Mon Oct 25, 2021 11:58 am

Floor pan sealing from underneath

Post by kjandb » Tue Jan 11, 2022 12:26 pm

Complete noob here, so go easy on me. I've been learning a lot from this site about replacing floor pans and got this far. I plan on sealing the top with POR15 and then seam sealer (is that the right order?). But I realized I have no clue what to do on the bottoms side - right now it's just raw metal. I'm thinking I should have used something on the bottom BEFORE welding it in place but I'm past that point. And I don't think using POR is an option any more. In additional to sealing the seams on the bottom side what should I use on the bare metal (or at least the part I can see from underneath)?

'71 Wagoneer - All stock (for now)
Avocado Mist

Posts: 14
Joined: Fri Jan 11, 2013 10:23 pm

Re: Floor pan sealing from underneath

Post by Atlasts » Tue Jan 11, 2022 3:36 pm

Jeep Floor.jpg
On the top side, I used etching primer and color matching paint. Underneath, I used etching primer, top code and 3M profession undercoating since my Jeep J10 was under coated when new.

BTW - I forgot seam sealer over the seams of the new patches.
You do not have the required permissions to view the files attached to this post.
Last edited by Atlasts on Thu Jan 13, 2022 8:30 am, edited 1 time in total.

Posts: 1600
Joined: Tue May 21, 2013 12:02 pm
Location: Lompoc, Sunland or somewhere between

Re: Floor pan sealing from underneath

Post by SJTD » Wed Jan 12, 2022 10:39 pm

I'd use some of the wax stuff inside the channel. Some sort of etching primer, seam sealer and paint on the outside then maybe some kind of undercoating.
Sic friatur crustulum

'84 GW with Nissan SD33T, early Chev NV4500, 300, narrowed Ford reverse 44, narrowed Ford 60, SOA/reversed shackle in fornt, lowered mount/flipped shackle in rear.

User avatar

Posts: 933
Joined: Sat Mar 24, 2018 3:11 pm

Re: Floor pan sealing from underneath

Post by Phils67 » Thu Jan 13, 2022 4:20 pm

A weldable primer before installing is what I've used on the lower ends where it meets the hat channels and such. Raw metal flash rusts overnight and just all downhill afterwards. I can't recall the company or product name but if you Google I'm sure you can find it, it's a metal sealer/coating that can be fogged into frames, hat channels, etc, basically any hard to get to spots and is applied after the welding is done (obviously when cooled). I believe maybe lizard liner but don't hold me to that. Finish with 3m professional undercoating. That's the ONLY undercoating I've ever used that doesnt turn into a sticky glue-like mess and actually holds up over time. If used anywhere you POR15, spray while the POR15 is still in the tacky stage or it'll just peel off later. Has to adhere to it.
1967 Gladiator J2000, 1998 4.0L OBD2, T18, D20 twin sticks, D44HD/D60, Detroit lockers, 3.73s, 4wheel disc brake, FSSR, Dakota digital, etc.

Posts: 44
Joined: Mon Aug 30, 2021 6:11 am
Location: Ellicott, Colorado

Re: Floor pan sealing from underneath

Post by akguy09 » Fri Jan 14, 2022 7:45 am

When I replaced mine, I welded in the bare floor pans. seam sealed and painted the inside. Then underneath I seam sealed primed and painted.
I figure it took 40+ years to get this bad, so I'll never need to replace it again....i'd be almost 90
1979 Jeep J-10 304/T-18
2017 Jeep JK 2DR
2021 PowerWagon

Post Reply

Who is online

Users browsing this forum: No registered users and 1 guest