Xj12c floorboard firewall seam


Hi first post time. Just bought car.
My first jag is a 76 xjc12 sans the 12. Stupid conversion .
Hope to fix that soon,
Only rust that was not surface I noted on my couple of hours of amateur inspection was the very thin metal at point where floorboard meets the firewall.
Floorboards and sills very solid.
Any opinions on fix not involving entire new floor panels?



(Frank Andersen) #2

Underneath the car, Cyderman - check that the drain plugs are sealing properly, and the general condition of the metal…

Water ingress will cause rusting in this area, which is insufficiently protected by inside rust protection. Serious rusting may indeed require new metal - standard replacement panels is probably not available…

xj6 85 Sov Europe (UK/NZ)

(Mark Lee (Pay Pal Patron)) #3

Floor panels are available at SNG Barratt. just say it’s for a Short Wheel Base Series 1; Short Wheel Base aka SWB Series II’s don’t exist according to SNG’s parts catalog. The XJC’s (6 & 12)'s started life as either a Series I’s or SWB Series II’s with a bit of welding here and there. The Coupe’s share the same floor and structural metal as the SWB XJ’s. if you look at the doors, you’ll see where the sectioned rear door was welded onto the front door. Time consuming - no wonder the Coupe’s were a low number production run.


Thanks I was a little worried with the blank not available linventories.

(John) #5

Doesn’t sound like you need an entire floorpan to me. Take it to any automotive welding shop and they’ll just bend some sheet metal to a 90 deg angle and weld it right in. If you’re adventurous, this is the ideal time to buy a welder and a cheap harbor freight sheet metal brake. The steel you’d get at Home Depot. Grinder and paint make you the welder you ain’t.


Ha! Trust me this car will have plenty of adventures before it hits the road. I don’t know how to weld but after looking at Sng pics Frank recommended I think you are right, floorboards solid. Just curvy part on bottom of firewall bad. Welder guy next door fortunately

(Carl Hutchins, Jr. ) #7

Two points:

  1. A gal did swap in a new floor board on her SII. learned MIG to do it. Very nice result.

  2. I have a HF MIG. I’ve not dome very well with it. I’ve done gas and stick in the past. Gas fairly well. Stick nt pretty but solid!!

  3. My SIII is almost rust free !! But, I did note that the
    flat part in the engine bay just over the pedals is thin!!
    Un molested and sound. I needed another hole. Easily drilled, I almost thought too easy!!

  4. Caveat. No experience here. But a view of a SWB car vs a LWB car indicates the length is in the rear doors !! So he driver foot board is probably shared.
    And, an after market panel is a great place to begin, should one decide to replace the entire panel

  5. Having a welder guy next door is a huge +.


(Carl Hutchins, Jr. ) #8

Just join clean metal to clean metal and the process works.

(Geoff Allam) #9

Carl. Quick comment about mig welding. Your difficulty is not likely your ability. It is the quality of the welder. My old cheap mig welder went up in flames and smoke last week so I needed a replacement. I found an unused high end Miller machine on the canadian equivelent of craigslist. Nice feature where you just plug in metal thickness and wire size and the machine sets itself. It also has infinate control for fine tuning. I could not believe the results. On my old machine the best I could so was to weld 20 gauge with multiple tack welds. The new machine produces a tiny stable arc that allows long beads with no burn through. I was amazed. Just a fyi for anyone contemplating a mig purchase. The expensive machines are light years easier to use than the cheap import ones.

(Carl Hutchins, Jr. ) #10


Agreed. MY HF unit is far from being on a par with the good stuff. Miller, etc. I did not expect it to be. but, not even close. Feed speed just not precise enough. Too fast, no matter the “adjustment”.

If I were to go back to welding, I would just refill my tanks and do oxy acetylene again. I did best there.

Or my son., an accomplished master of TIG!!!
But, I’m not Precious vision appreciated a lot more. Cataract in right eye fixed. Left next. another issue there to be fixed first. It on the calendar for next week.

Enjoy your find…

Timing not yet set


Thanks guys. I know some people find the joy in learning how and doing everything on their project. If I can do the reassembly and track down and install a decent v12 and drive it before I cease to exist, that will be accomplishment enough. Only sixty but this is my first jag.