Tail Light Panel and Trunk Floor – Part 4: Left Rear Quarter End Cap

This blog entry will be refreshingly short and sweet.  After finishing the corner repairs, I needed to get the rear of the quarter panel back into solid form before I could install the trunk floor panel.

In an earlier post, I mentioned how pleased I was with the quality and fit of the replacement quarter end caps I purchased from NPD.  There are many who would complain about the fact that this one-piece stamping takes the place of two at the lower trunk opening corners, but I am quite happy about this feature and think the repair is that much easier to make with less chance of rust down the road.  We’ll see if I have the same opinion when the tail light panel installation comes about.

Anyway, the key to getting these end caps to fit the quarter as intended is to use the original body alignment holes as guides before clamping the panel in place in as many locations as possible to make sure the fit is tight and right.  I use large, round steel drifts to align these holes properly.  Once I am satisfied with the fit and location of the panel, I clamp everything in place using as many clamps as I can manage.

I started the installation at the trunk opening corner area to make sure the trunk lid sealing bead was nested under the original panel correctly.  Once this fit was established, I tacked the plug weld holes in the original spot weld locations to lock things down and moved on to the rest of the panel to get everything tacked in before final welding.

With the panel fully tacked into place, I could move my clamps around to provide support as I started plug welding each hole, moving around the panel randomly to reduce warping.  One rather tricky area to weld was along the top edge of the quarter panel.  The original spot welds were very high on the panel (almost to the outer skin surface), leaving considerable open space above the patch panel that would need to be welded closed.  By using a strip of copper plate clamped behind each hole as a backing and heat sink, I could carefully plug weld the patch and fill the hole at the same time without distorting or burning through the body surface, even though the plug welds extended right to the very edge of the character line.  While I was at it, I also took the time to repair a small stress crack that had migrated to the outer skin.

With all the welding done, I was able to grind each weld smooth, making the fender extension seating edge a perfectly flat fit against the extension itself.  Now, with the structural integrity of the rear quarter vastly improved, I could move on to the trunk floor installation without fear of pulling the rear quarter out of shape.

Body alignment holes can be very accurately aligned using long steel drifts and plenty of locking clamps.

Here is a close-up of the drift used to align the body alignment hole and one of the many clamps I used to keep everything right where it needed to be.

Here is the drift locating the top alignment hole.  Also note the gaps at the top of each weld hole above the edge of the panel.  This was due to the factory spot welds being very high on the edge.

After tacking the panel in place, I started the final welding at the top, where the trunk opening lower corner and seal bead meet.

To fill the gaps shown a few photos back, a copper backing plate was clamped behind the holes along the top of the panel to allow a complete weld without "whiskering" out the back or burning through the quarter skin surface.  While I was at it, I repaired a small stress crack, seen just to the left of the photo.

Working all the way to the bottom with careful plug welding, the panel fit turned out spectacular.

Here's a view of the fully welded end cap in place and ready for weld smoothing.

And here's the finished installation.  The quarter panel now has significantly better structural integrity and will not move around when the trunk floor is installed.