Does anyone know what would be involved in converting the rear lapbelts in a '88 coupe to the '90+ shoulder belts?
My son is moving from a car seat to a booster seat and I want to use the safer shoulder belts on him.
I went through the same thing several years ago with my 87 hatch. Since you have a coupe it should be a bit easier. You can try and remove the welded in plate the the seatbelts mount to in a 90-93 coupe, along with the belts and the carpeted retractor cover, and weld it into place under your package shelf. Or you can fabricate some kind of reinforcement plate for under the package shelf and use some of the long seat belt bolts through the reinforcement plate and the shelf. Then mount the belt retractor to the bolts and tighten them down with some nuts. The belts should bolt up in the stock places, the other end of the sholder belt goes where the lap belt retractor is now. I ended up keeping both belts, the lap belts and the new sholder belts since the lap belts actually lock in place better for infant car seats, but the sholder belts are better for older kids and the booster seats.
Yes, like trbkrb, I did the same on my '87 Hatch.
The hatch required I install the quarter panel interior pieces from a '90-93 as well.
But you have to weld in the shoulder harness assembly to the top of the tower. I had it done by a local professional. We removed the old lap belts and installed the new belts, but kept the old seat cushions, as the seat bottom is a different design and secure differently. The latch end of the belts stick out a little more, but really no problems. I did this when my boys got a little older requiring the shoulder harness. The toughest part was procurring the parts, and dying the panels to match.