Driver’s A Post Rebuild

With the bones of the driver’s A post (or hinge post) having stayed mostly intact, I should be able to breeze through shoring up and skinning this side. It was fairly straightforward but this type of work for me, though enjoyable, is not necessarily a breeze. I first decided what metal needed to be cut away. Both the lower outer face and the lower “box” had perforations from rust, so those parts had to go. A grinder with cutting wheel did the majority of the work. On the box, due to less clearance, I used a right angle die grinder with cut off wheel. Not cutting out the lower part of the hinge post (where the hinge mounts) saved me the trouble of the precise measuring and placement of the new hinge metal. I had purchased a driver’s inner a post structure so it would provide donor metal material. I was able to then just fit up, weld, grind, and paint the inner structure.

The outer skin requires precise alignment and a bit more aesthetic fuss than did the inner structure. I started the process by figuring out how far up the A post skin I wanted to replace on the car. In my case, on both sides I did not extend all the way to the windshield provision rectangular holes. I cut the replacement skin first and began fitment and trimming away at the car’s A post skin. I had a little difficulty getting the lower A post skin to not sit proud of the outer sill. I trimmed some material from the back surface that meets the footwell box. Eventually, I broke out a big C clamp to fully convince the skin to cooperate. After double-checking that the post skin was 90 degrees to the outer sill, some welding tacks to the horizontal surface of the outer sill kept this in place.

Next, I folded over the A post skin flange onto the inner structure as was done on the passenger side. I found this to be easier if I started tapping the fold over prior to putting the skin on the car. With the flange angle somewhere less than 90 degrees, it helps to more easily fully fold the flange with channel locks (and a wood block to protect the surface). The skin was plug welded in four places to the inner structure face, also to the footwell outer skin and to the back of the hinge post boxes. Where the new A post skin meets the old, the joint was butt welded, taking care to manage the heat to minimize metal distortion. All the welds were ground down with a flap wheel and 1/2″ belt sander.

While this side did not need as much structural work, it did provide its own set of challenges. One was the condition of the firewall along the face adjoining the windshield cowl. It had some rust and some other drilled holes. Additionally, in prepping the area for repair, a huge chunk of filler was removed from a cavity. I trimmed up the area where the new metal would be installed and worked on a cardstock template. This ended up being an interesting shape and fit as it needed to go behind the new skin but butt up to the firewall’s old metal. As far as the holes go, I was able to weld them up except for the threaded hole that’s used for installing the fender. The windshield cowl is going to need some love, but that’s later down the road.