Tech Tips :: Your Web Site Name Search ::

Tech Tips :: C4 Related Tech Tips :: Early Convertible Top Installation and Glass Retrofit

Information

It is possible for novices to install a glass window top to their early C-4 convertibles. I should know, I am as novice as they get! For 86-93 Corvette owners that can no longer stand their plastic window, here is my experience in converting the vinyl top to cloth with heated rear window. First, let’s start with the supplies and parts you will need: Stayfast Cloth Top – Robbins: http://www.robbinsautotopco.com/pdf_files/page47_49.pdf http://www.convertibletops.net/Corvette%20-%201986-1987.htm Installation Video – John’s Corvette Interiors http://www.johnscorvettecare.com/convert.html 3M Weatherstrip Release Agent – Zip Products http://store.yahoo.com/zipproducts/zip-ws-4482.html Two tubes of 3M Black Super Weatherstrip Adhesive – available at Wal-Mart and Pep Boys 3M Fast Tack Adhesive – 1 Tube 3M Part Number 08031 – Pep Boys Beers consumed – 1 six pack Convertible Top Retrofit Kit, 86-93 that permits these years cars to upgrade to the glass window convertible top: 12522961 Convertible Top Retrofit Kit GM Weatherstrip – 5 Pieces (required): 17987731-LH - Horizontal piece at top front of door window 17987732-RH 10273003-LH - Vertical piece at rear of door window 10273004-RH 14092676 - Back Bow The following piece is easy to replace if you need to while your doing all the others: 10268887 windshield weatherstrip The following two pieces are really not needed if yours is in good shape 10269867-LH - Horizontal piece at top rear of door window (not needed) 10269868-RH Jeff Kopp Superior Chevrolet Wholesale Office - Parts Department Time to complete the job: Removal of old top: 2 Hours Installation of Retrofit Kit: 3 Hours Installation of new top: 6 Hours Tools Needed: Sharp razor cutter for trimming Trox screw set file Phillips screwdriver Assorted slotted screw drivers Drill and lots of sharp bits Pop rivet installation tool Assortment of small (1/2”) brushes for spreading glue Needle nose pliers, straight and angled Penetrating oil Small scrapers to remove old weatherstrip adhesive Lots of Rags Denatured Alcohol Lots of Beer Latex gloves General Comments: The videotape that shows you how to remove and install a new top was most helpful. I do not think I could have done it properly without it. I had a VCR/TV in the garage to watch it as I was going though it. This video will NOT show you how to install the retrofit kit. It will show you how to go thru the job and get it on straight. I choice to break the job into three parts, removing the old top; install retrofit kit, install new top. So I was able to complete the job in a long weekend. Make sure that all the drill bits you use are sharp. Otherwise you will get elongated holes and other problems. Also use fresh razor blades when you go to trim the convertible top under bow 5. You must be very careful and not slip or you get to buy a second top. I changed razor blades about 3 times. A fresh blade will cut through the excess material like butter without any frazzling. Make sure that you have an electric soldering iron with a fresh tip that has never been used before to make small cuts in the stays (which is the material that hold together the bows). The defroster wires go through these slits. If you just cut it the material it will unravel. SURPRISES: My weatherstrip looked pristine and was the original 11-year-old stuff. But I knew it was original and was not sure if it would survive removal and replacement. I do not think it is possible to reuse the crappy GM weatherstripping if it is old. I went ahead and order all new stuff. Good thing I did. Even though the weatherstrip (except for the windshield piece) I had on the car looked great, it disintegrated upon removal!!!! I had ordered the seven pieces needed for complete replacement for the top. If yours is in good shape, there are two pieces that do not need to be removed. These are the pieces that are on the top rear of the window. This would have saved me more than $60. Be sure to use a zip lock bags to bag and mark where all the little parts go. Otherwise they will beam up to parts heaven. You will no doubt find at least one screw that the GM torque monsters will have secured down to 1,000,000 ft/lbs. I had to drill out once screw in this job. You may also need to find those little plastic screw like devices that secure down the weatherstripping. It seems that they have a habit of ‘beaming up’ and cannot be found. The GM instructions for the retrofit kit are very lengthy. There is one section which described installing some bumpers to bow #5. The illustration on this step was not clear. You will need to carefully examine the overall drawing on the first page to see where this part really mounts. The installation of the retro fit can be confusing. Take your time and remember – MEASURE THREE TIMES AND DRILL ONCE!!!! The rivets that the GM kit supplied were steel rivets and were quite rusty. You will need superior strength (i.e. many beers) to get these rivets on securely. I also knocked down all the rough edges of these four rivets with a file and coated them with silicon seal to prevent anything from snagging against them and cutting the headliner or top material. These are the rivets that connect a spring to bow four. There were also several smaller steel rivets that were supplied to connect bumpers to the bow #4 headliner retainer. I replaced with some fresh steel rivets rather than struggling with rusty ones. They also provided a small amount of double-sided tape that was too old to be useful. I could not understand what its purpose was anyway, so I did not use it. There was one main shock I had after the top almost fully installed. I only step I had left to do was to install (and glue) the top to the front bow. But before I did I figured that I would see how the top came down and stored in the storage compartment. When I tired, it seemed the top would not go down far enough to allow the compartment to close! I was appalled! I spend over an hour going over the retrofit kit instructions to see what I had screwed up. Could not find a thing. I tried closing it a dozen or so times. Slowly up and down, up and down, slowly. BIG TROUBLE!!!! Or so I thought. But even though I was about my wits end, I decided to plow forward. Good move! As soon as the front of the top was properly installed, it went right down into the compartment – no problem!!!! Cleaning up the weatherstrip retainers to get off all the little bits of glue is the most time consuming and messy part of this job. The 3M Release Agent will do it. I was told that you can also use ‘decal remover’ for this purpose. You need to soak the stuff several times to get it all out. BTW – unless you like shrieking in agony – wear rubber gloves because little cuts on you hand do not mix well with this chemical. I found that a combination of using flat screwdrivers of various sizes flowing rubbing with a rag sprayed with the chemical will help scrap the goop out of all the channels. I also used denatured alcohol to wash everything down before reinstallation. You may also want to obtain a roll of thin black double-sided tape to apply to the back of certain weatherstrip retainers. Evidently GM uses it on some of them and the tape will not survive this process. I just used a very thin bead of the 3M black glue. I also ran 400 grit sandpaper of the back of the weatherstrip before gluing it down. POST INTALLATION: Your top needs time to adjust to the frame. Robbins suggests leaving the top up and in the sun for 5 to seven days. The creases created during shipping show when the top is up. Hopefully, this will disappear with the sun’s heat treatment.