Back seat bottom:
The bun has a wire lashed onto the frame in a slot on both sides of the center panel of the seat (see pic below).
Install a pair of wires in the upholstery sleeves.
Upholstery inside out,...align upholstery top edge and bottom edge evenly and set sleeves in slots. If you feel from below, you can feel where the bun wire is at. Working from the 'seat' side of the center panel, grab the center of the upholstery sleeve (wire inside) with the hog ring, push down to the bun wire and clamp the hog ring. Apply four hog rings along the wire, working from the center, out, and repeat on the opposite side.
Apply contact cement to 'seat' area of foam bun and upholstery.
Align all corners. Roll each front corner over and align front edge of upholstery. Roll each rear corner over. Smooth down each 'seat' area to adhere the upholstery.
I added a little foam to the curved front of my bun (to smooth the vinyl), but began setting hog-rings there, and working outward. Front edge first, along each side, then the back. Here's where I set my hog-rings, and my result:
Rear seat back needs a mounting tab welded before proceeding with it,...being arranged now.
My repaired original front seat frames and buns are now ready for the new upholstery:
Front seat back upholstery inside out, readying for installation...This is how the upholstery wires for the front seat backs are secured to the seat springs - heavy Italian "rubber bands":
We will see how those fit the front seats,...test fit of buns seemed good, but I find a couple of things different with my early 1979 car and the 1979 - 85 upholstery. I know that a number of changes to the cars occurred in 1979,...
I'll have to make openings in the upholstery for the seat belts to go through the rear seat back. And the front seat bottoms have XXL sized skirts,...but I've already figured out how to fix that nicely.
More very soon.