by HAULIN' IT » Thu Apr 30, 2009 3:58 pm
I'm assuming what you have is refered to as a "Pittsburg seam", the flat tin goes into the half moon part & "locks in"...maybe you have the flat part upside down?
To mount the tubs, it's best to use rivets into the framerails (welding the thin metal to the heavy can be difficult). At the quarterpanel side, this can be done several ways. I prefer that the original wheelhouse be left in (assuming it's good) up several inches from the wheel lip, a flat piece of tin welded up forming another half moon looking piece to attach the curved part to. This leaves a gap between the quarter & tub so viration/twisting doesn't effect the outer panel. Another way (more common) is to remove all of the original wheelhouse & attach the new tub to the backside of the quarter panel. Chris Alston chassisworks or Art Morrison had a nice write-up on installing them some years ago. If you can find it, it will be helpful, if not I'll try to give you the basics. Put the half moon piece up in there where you want it, roll a piece of cardboard the shape of the other part making it somewhat close to the quarter panel shape, tape it to the upright piece & the quarter in several places. Now use a flat stick about 2" long (piece of paintstick works) with a hole drilled in one end for a marker tip to go through to run along the quarter panel with the marker drawing the shape 2" away, but on the cardboard, take the cardboard out, cut on the line, line up the back edge with the Pittsburgh seam...Turn the tool around & now follow the cardboard edge...drawing the correct contour onto the tin. Now here is where my thoughts are different again, instead of cutting on this line, measure out 1" all along it & cut there, now make cuts as needed so you can bend the 1" lip upward, this gives you a nice, wide surface to put a quality urethane seam sealer to "glue" the tub to the quarter panel, this lets the tub flex without distorting the outer panel, but gives a surface to glue to instead of just the edge of the tin. My Two cents, if you need farther explaination...I'll try to do better, Lorne