68 top installation questions...

[Dave Suesz]

I'm putting a new top on for a guy, and the one I just took off is not the original. Looking at the tops, I think I should:

Install new pads
Attach the rear edge (at the decklid)
Attach above the window panel to the rear bow
Run the cables through the sides
Attach the vertical WS and side of top
Attatch front of top to header bow
Attach white bead to front edge of top
Install WS

How far out from under the front edge should the white bead protrude? The one on the car was RECESSED 1/2"- I know THATS wrong

For the seam cover above the rear window, the mfr gave us a strip of matching vinyl and a 3/8" foam roll. This is nothing like what was on the car- What do I do with it?

There was also a 4' long 1/8" nylon cord. Whats that for? Again, nothing like it on the old top.

I've rebuilt engines and transmissions, but this is new to me.

[Wayne W.]

Re: 68 top installation questions...

The 1/8" cord is to attach the rear bow weatherstrip with. The strip of material and foam bead is to make up your own front filler, however 3/8 is way too thick. Top Mfg just cant seem to get that straight. The correct stuff can be found in hardware stores. It is about 1/4 and has a mesh flange on it. The rear seam over the window should be covered by a wireon strip and two end caps. Sounds like the old top was installed at Bubba`s Upholstery.

[Dave Suesz]

It's becoming more clear now...

Since bubba made both the front filler and the seam cover over the rear window, I had no good model and switched them. No fool I, no attempt was made to tack them on that way. The top has a 1/8" bead in it to attach to the rear bow, it appears the rear seal itself wedged into the larger rear slot. It's junk, practically crackled as I pulled it off, so he'll be bringing over a new one, a full set in fact, they were all original (only 36 years old!). Top mfr actually included 2 front foam rolls, 2 1/8" nylon cords, 2 rear seam covers, and 2 pair of seam cover end darts.

Header bow tacking strip was dust, I got a perfect vinyl replacement at the Mustang Barn. Hey, you try to find OTC Corvette parts on Saturday afternoon!

One last thing- I do the rear edge first, then middle seam, and front edge last, right?

[Wayne W.]

Re: It's becoming more clear now...

I guess that there are a lot of ways to do it, but that is not the way I do it. I do the rear first. Then check the fit at the window post and then go to the center seam and locate the rear bow at the correct location and attach the top of the straps. Then I go to the front and temporarily attach it. Then go back to the center seam and pull and check before final tacking that and the front. The front filler goes just under the edge of the front. It neither sticks out much or goes under much.

[Michael D.]

Re: 68 top installation questions...

Dave
Corvettes use a measurment from the bottom of the last bow to the bow above the window. THIS IS IMPORTANT. Not all manufactures use the same exact measurment. I use Electron Tops. Bow hieght for the 68-75 vettes is 15 1/2". 63-67 19 1/2" 61-62 15 3/4" 56-60 15 3/4" 53-55 15 1/2".
Strip the old top and measure the rear bow with the pads still in place, to the next bow up. The first thing to do is put new pads on the frame, but you need to have a measurment from the deck with the rear bow latched. Measure the rear bow from the center of the deck, bottom of the bow, to the center of the next bow up which would be the bow above the window. This is a critical measurment. Most top companies will send the measurment with the top. It could be 15-19 1/2".NOT setting the bow height before installing pads and top will cause serious fitting problems. After you get the bow height set and the pads on put the cover over top of the conv. frame and put the side cables through the pockets and fasten them to the frame, then glue the rear bow section to the frame start at the center, there is a center mark on the frame to start at. Next,pull the material to the front, latch the rear bow down and put the top in the "UP" position, pull forward and mark with chaulk. At this time check the above window bow and the top itself to see where the seam is at. The seam should be close the center of the window bow. If it is not pull the top material foward if you can and remark it. If you cannot pull any more remark the chalkline the distance it would take to get the seam centered. Unlatch the top from the windshield and rear bow, glue the front of the top 1/2" back from the the chalkline on the underside let the glue tack well than set the chalk mark just under the front edge of the front bow and stick it down. After that glue the side channels to the frame, close the top to see how it fits. You may have to remove and reglue until you get the fit you want. The next thing to do is heat the window with a heat gun or hair dryer and pull it up and attach it to the bow while the top is in the up and latched position.Becareful you don't distort the window. Next pull the rear section of the top to the back bow and attach it to the same bow. Now you can put your "wire-on" on. Don't go more than 3" from the seams that run down the sides of the top. Put the chrome "wire-on" tips on. Most corvettes/cars used a 1/2" round rubber. I prefer to use the 3/8" rubber, or you can use 1/4" rope or round rubber for the front header. That piece should fit to the edge of the framework or slightly pulled under so when the top is latched it will act as a seal as well as finishing off the front header. Install the weather strips and hopefuly you are done. Good Luck, MikeD #1787

[Harmon C.]

Re: 68 top installation questions...

Dave The hardest part is the first thing after the pads and that is streching the material around the rear bow and getting the correct fit at the back of the window on both sides. On an Al K. top it takes heat to get it right. Look at some tops and you will find more where that bead will be off than correct. I have seen lots of installations 3/4" off on that bead.An Al Knock video would be very helpfull and has great tips. Lyle