Well, a new-to-me soft top. A member of our local Triumph club replaced the top on his TR6 with a fancier cloth version, and his old one was still in pretty good shape, and I was the first to respond. The only 2 problems with it were a small hole in the rear corner and that it had been installed a little too tight on the previous car. So this isn't a new top installation, it's really a re-installation of a used top that's still a lot nicer than the one I'd patched and repaired several times.
The VTR installation instructions are pretty good, if lacking in photos. Ed's TR6 restoration site has a good page on his his new top installation with photos. I don't think there's much unique about mine other than reusing a top, and I found the installation easier than expected, but I thought a few picture of some details might be helpful for others.
I started by removing the old top, sanding a few spots on the frame with surface rust and painting it. I let it dry for a few days before starting on any gluing steps. In hindsight, I should have given it a couple more coats and let it dry longer, as I dinged up a couple of spots during the installation. Powdercoating is probably the best way to go if you have the time and money for it.
With the frame installed I did a lot of test fitting with the door windows, the top needed a bit of tweaking to align correctly to the windshield top. One of the hinge pieces also seemed a bit bent, so I realigned that to match the other side. I wanted the mount holes to align with the frame sitting naturally, without needing to flex to fit, so there wasn't any built-in tension before mounting the straps or vinyl.
In my previous patching of my old top, I replaced the shredded velcro on the side rails with new pieces bought from one of the usual vendors (I don't remember which), but the velcro was 3/4" wide - too wide for the rail edge, so the vinyl didn't wrap around the rail cleanly and ultimately came loose again.
I tried using a water-based contact cement on some test pieces to see if that would work. I've had good luck with using that for the vinyl covering on my speaker cabinet project, but it is not a good choice for this. WBCC is thinner, so you need to add several coats to get a good base of adhesive on porous surfaces like the cloth lining of vinyl. It also take a long time to dry, so you're waiting 30-60 minutes for a coat to dry in good weather. And after all that, it didn't stick as well either. I ended up using standard solvent-based brush-on Weldwood contact cement for the side rail velcro and 3M 90 high-strength spray adhesive for the front rail. You could use the spray adhesive for both, I just found it easier to brush that area rather than mask off so much.
I sewed my own side velcro pieces from heavy-duty sew-on velcro trimmed to 1/2" wide and sewn on to some black automotive vinyl bought at the fabric store. Very little of that vinyl shows after everything is done, so there's no reason to get fussy about the specific vinyl pattern. I could have cut up pieces of the old top for the vinyl base under the velcro, if I'd been planning ahead better.
I made a new foam wedge for the front of the rail, it's a little bulgy here, but works fine with everything installed. The wedge was missing in my top, but it looks like the goal is to make a smoother transition between the side and front rails.
Laying out the new straps, I left the rearmost bow down while fitting the strap to the front bow. By attaching the front end of the strap and then raising the bow, I was able to add more tension to the straps without pulling as hard on the strap while marking the front mount.
When attaching the front end of the strap, it gets looped around the hold-down plate. This puts it closer to the top fabric and gives extra clearance around the levers. I haven't trimmed the excess strap yet in this photo.
Once fully installed the straps are tight enough to make a fairly high tone when plucked, but it's still fairly easy to align and clamp the frame down.
I was doing the install on a moderately warm day, but in direct sunlight, so the vinyl had a good amount of stretch. Since I knew the top had fit a bit too tight on the previous car, I aligned it about 1/4" looser along the front edge than the previous line showed. This seemed to pull the top smooth without being too tight.
I masked off areas that shouldn't get glued and used 3M 90 spray cement on the front rail and front edge of the vinyl top. Unfortunately, since it had previously been trimmed to fit the old setup, installing it a bit more slack means that the edge of the vinyl doesn't extend under the riveted-on seal channels. I trust the glue will hold well enough.
On the inside I replaced the mostly broken plastic studs on the rear bow with new metal ones, and added studs to the 2nd bow rather than rivet the top directly to the bow.
This is the best way I've found to install the difficult front seal. I sprayed the bottom of the rubber with some soapy water, pushed the far edge into the channel, then used a short flat-blade screwdriver to poke in the remaining edge. It's tedious but took maybe 5 minutes to finish.
The final installation turned out smooth and fairly tight, but not too tight to latch down in front. It takes just a little extra grunt now, but I think it'll be fine after a few days in the sun to stretch and settle in.
In the rear the side snaps line up well enough that I didn't have to remove and reinstall any of them, but one was a pretty tight pull at first. The rear window is not very tight, but after being up for a day the quarter windows have straightened out quite a bit.
On the first highway drive, it's obvious that the new top is better sealed than the old one, and there's almost no creaking or rattling from the top. And even with the waviness of the plastic it's sure nice to be able to see out the back now.