Floor pan fire wall connection

[jeffc280sl]

I'm replacing the drivers side floor pan and planning to patch the fire wall.  It would seem that I have an alignment issue at this connection.  The floor pan has been completely removed.  If I place a straight edge on the transmission tunnel at the bend where the fire wall and floor pan meet and continue it across to the side rail I have about a 1/4 inch gap between the straight edge and the frame support piece which runs between your feet under the floor pan.  Since this area had been tampered with by the PO I do not have a reference for how it came from the factory.  Should the frame support be built up so that it mates nicely with the fire wall floor pan connection?  Any help would be appreciated.

Thank you

Jeff C.
1970 280SL 4-speed

[Khurram Darugar]

Jeff,

Where the floor pan meets the frame rail, spot weld across the top of floor pan along both sides of the rail.  This will ensure that you have no gap between the framerail and the floor pan.  Once this is done you may want to seam weld from below. (Although this was not done oringinally)

After that butt weld the rest of the panel into the correct place.  
A couple of tips in regards to this panel:-
If you got your floor pan from KK (And its thinner that the other panels) panel warping may be an issue (did'nt have this happen on any other panel).  Tack weld the corners and around the bend on the trans tunnel.  

Good Luck

Kay

[jeffc280sl]

Thanks Kay,

Thanks for the advice about warping along the trans tunnel seam.  

The fire wall panel covers the fire wall and then makes a horizontal bend of about 3/4 inch to fit under the floor pan.    It is this seam that is the issue. I'm using 18 ga steel to patch the fire wall.  As this piece comes down from the fire wall and takes the horizontal bend to fit under the floor pan it does not extend down far enough in the center to sit on the frame section between your feet.  Alignment is fine from the trans tunnel across to the frame rail but this piece does not make contact with the the center frame section.  I can butt weld the floor pan sides.  I can also "form" the fire wall so that it makes contact with the center frame piece to get a tight seam.  By design I would have thought the German engineers would have made a better fit.  I'm just wondering if I'm missing something.

You also indicate the floor pan was not welded to the center frame piece.  It must have been joined with a seam sealer of some sort then.

Thanks

Jeff C.
1970 280SL 4-speed

[Khurram Darugar]

Jeff,
     I believe a lot of the welds on my car which i am pretty sure had all original panels were resistance spot welds.  So it is welded but not seamwelded.  The seam on my car was very close and tight as to not allow anything in.  Ofcourse then theres years of hardened  undercoating.

I did some forming in the area that you are talking about and am happy with the result aesthetically.  I would agree that there is something wacky on this panel in terms of fit.  But i too could have missed something.  I would still form and not fill though.

In DIY terms i am about average/average skill level (getting better as car progresses) and patience.  

listening to classical music in the garage really helps keep me chilled out!  
Kay

[jeffc280sl]

Thanks again Kay,

Great comments.  I'll try the music too.

Best,

Jeff C.
1970 280SL 4-speed

[Benz Dr.]

The floor pan IS welded to the center floor rail. I used to drill holes in the floor pan and then plug weld it to the rail.
You can get lower fire wall sections so no need to make them. I try and place the seam right down the centre of the rail so that on the outside of the car nothing will show. This piece can be plug welded on to the frame rail the same way the floor pans are done. This is a lot more work but the results are a repair that looks right and isn't so easily seen.

Dan Caron's
 SL Barn
benzbarn@ebtech.net
 slbarn.mbz.org
  1 877 661 6061

[jeffc280sl]

Thank you Dan!

Your advice is always appreciated.

Jeff C.
1970 280SL 4-speed