Installing a Convertible Top

Fortunately for those of us who own open cars, replacing their tops isn't that difficult. With a little care and a modicum of patience a hobbyist restorer can do a good job at home without expensive special tools. The basic techniques for installing a top on a convertible are similar enough on any of them that the following general instructions, plus your car's service manual, should be all you need to tackle the task.

A little history

Open cars have been around since the beginning, and are still being made today in much the same way they were in the in the old days. Only the materials have changed. Surprisingly, at the turn of the century and into the early twenties, most cars were open. Back then, people didn't use cars daily to go back and forth to work. In the cities and towns of the era, public transportation was common and inexpensive. Cars were generally used for weekend outings. Another reason most old cars were open was the fact that safety glass had yet to be invented. As a result, a collision in a closed car could mean serious injury. Especially when you consider that early cars were designed with lots of headroom and huge windows to allow even tall gentlemen to sit upright and wear hats while driving.

While tops, and top mechanisms haven't changed a great deal over the years, there have been a few innovations, as well as some resulting changes in terminology. Early open touring cars were often called phaetons, as were the open carriages that preceded them. The term was derived from the name of the Greek god Phaethon, son of Helios the sun god.

Phaetons are open sedans that have no roll-up side windows. Instead, they have side curtains made of the same material as the top, but with plastic or celluloid windows sewn into them. Likewise, many people today call any open two passenger car a roadster. Actually, a roadster is an open two seater that does not have roll-up side windows. If an open two passenger car has roll-up side windows it is called a convertible coupe. And if an open four passenger car has roll-up side windows it is properly referred to as a convertible sedan. (Early '30s convertible sedans were also sometimes referred to as all weather phaetons but this term has gone out of fashion.)

However, whether your open car is a 1920 Model T, a '49 Plymouth or a '67 Mustang, and whether or not it is a roadster, phaeton, or convertible, a new top is very likely available for it, ready to install. All you need to do the job are a few tools, a good eye, and a little patience. Here's how.

Off with the old

Getting your old top off isn't a big problem, but don't remove it until you have received your new replacement. Chances are you will need to order a top through the mail. If that is the case, make sure you tell the company supplying it the year, make and model of your car, and which fabric and color you need. New tops for most older cars are available from a number of sources. Here are a few.

Kanter Auto 76 Monroe St. Boonton NJ 07005-1292 Orders 800 526-1096 Info 201 334-9575 FAX 201 334-5423	Ciadella Enterprises (Chevy and Corvette only) 3757 E. Broadway, Suite 4 Phoenix AR 85040
J.C. Whitney Co. 1917-19 Archer Ave P.O. Box 8410 Chicago Ill. 60680 (312) 431-6102	Denning Automotive PO Box 28 Springfield N.J. 07081 Orders 800 344-6464 Info 201 379-2335 FAX 201 379-7119 (Free installation video with purchase)

When you receive your new top, place it over your old one and compare the two of them to make sure the new one fits, and that such items as snaps, seams and flaps are configured correctly and in the right place. This is much easier to do with your old top still on the car. If your new top has any deviations from your old one, first make sure the old one is correct for your car. It is possible that you do not have the right top on your car in the first place. On the other hand, if you discover that your old top is correct but your new one doesn't match, send the new one back and request the right one.

Compare your new top to your old.

Marking the locations of boot studs.

Remove the weather stripping.

Remove the studs, but watch for the pads.

Examine your existing top pads. If they are loose or flat, fluff them up or insert a little of the correct foam or cotton padding as used on your car. Next, inspect your rear top bow. These have a tendency to slip out of place through repeated raisings and lowerings of the top. Because the pads help position the rear top bow, never untack more than one end of a pad at a time.

To check the positioning of your rear top bow, place your new top over the frame and snap all of the fasteners in place. Check to make sure that enough fabric extends over the front trim rail and the rear trim rail to permit proper tacking. Now examine the point where the top deck is sewn to the rear side quarter. Point A must lie on the center of the tacking strip of the top rear bow.

Centering Point A on the tacking strip.

If the top bow is too high, so that point A is below the tacking strip of the rear top bow, untack the left side quarter pad at the at the rear trim rail. Pull the pad down until Point A is in its proper place on the left side of the car. When it is correct, re-tack, then do the same thing to the right side of the car.

Finally, take the top off the frame and check the alignment of the rear top bow by measuring the distance from it to the rear trim rail on each side of the car. These measurements should all be equal. Now tighten all of the nuts, bolts and screws that hold the frame together.

On with the new

Before you begin installing your new top, you will need to add single cord welt on the front and rear trim rails. Single cord welt is a trim material, typically 1" wide, that comes in rolls. It has a rope like beading inserted into it, and it is gummed on one side. Cord welt is tacked in place on the front and rear trim rails and goes between the rails and the top itself. You must have the single trim welt in place before installing the top. Space your tacks 6 to 8 inches apart and make sure the beading is down and the gummed side is against the trim rails, so the side of the welt that is completely colored is facing out.

Tack the cord welt between the rails and the top.

If your car has a glass back window, now is the time to remove it from your old top and install it on the new one. Remove the glass and frame from your old back window curtain. Don't forget, after you have removed it, that the outside half of the frame is the one with the studs or bolts. Examine the material around the glass. If it is damaged or worn, fold some old style rubberized electrical tape around it to act as an insulator and seal. Some older cars have the window frame covered. Others are painted or chromed. If yours is rusted and in bad condition, paint it or have it plated.

New tops usually come with perforations in their back window curtains so you can locate the studs for the window frame. Place the outside window frame on your work table or on a clean floor. Place the outside surface of your new curtain on the outside part of the frame. Now locate the glass in between the studs on the inside surface of the curtain. Place the inside frame over the glass, then tighten its screws evenly in place. Don't over-tighten and crack the glass, just snug up the screws. Don't cut the fabric out of the back window frame until after your new top is installed.

Whether your back window is glass or a later plastic one, there are 4 common styles of back window curtains. The first is the 2-zipper grommet type, the second is the strap and rivet type, the third is the three zipper type, and the fourth, and most common on later cars is the all-around zipper type. Here are instructions for each type. Follow the instructions for your type only.

Take the metal bar out of your old rear curtain and insert it into the new one. Attach the straps to the new rear curtain exactly as they were attached to the old, using new rivets. Close the zippers all the way. Now, on the inside of the car, slip the straps through the brackets and pull up the curtain so that it touches the rear top bow, then buckle the straps. Skip down to the finishing the curtain instructions.

It is very important that the rear curtain be centered. Close the zippers all the way. Your new curtain probably has a centerline mark. If it doesn't, you will need to establish one using a measuring stick. Now, using this center mark as a guide, tack the top of the curtain to the center of the rear top bow. The metal part of the zipper should be at least 3/4" below the rear top bow. This will insure that the zippers will be accessible for easy opening and closing on the inside of the car. Complete the job by following the instructions below.

Finish the curtain

At this point don't drive the tacks all the way down. Pull the bottom of the rear curtain down as tight as you can and tack it to the center of the rear trim rail. Start at the center and space 3 or 4 tacks in either direction. Now tack alternatively back and forth until you have tacked across the bottom of the curtain up to the zipper tapes. Now tack the zipper flaps to the rear top bow, (The flaps are the long pieces of fabric to which the zippers are sewn.) making sure to keep the flaps tight and in line with the curtain.

After you have finished tacking the flaps, slide the zippers up and down a few times to make sure they do not bind. If they do, untack the flaps, adjust them, then re-tack them into place. Trim off the excess material, then drive the tacks all the way down. Now, with the rear curtain in place, you can trim off the material that covers the rear window glass. Using a utility knife with a new blade, or a new single edge razor blade, and using the window frame as a guide, carefully trim away the fabric.

On with the new

Place your new top over the frame and snap into place all of the fittings where possible. So you can make minor adjustments later, don't drive your tacks all the way down at this point unless specifically advised to do so. There are two kinds of tops commonly used on older cars. These are the valance type, and the frame, or U type. Follow the procedure below for the kind of top you have.

Installing the valance type of top

Illustration A

Pull the top toward the back of the car evenly, so point A falls into its proper place on the rear top bow. Adjust the top so it lies smoothly. When you are satisfied, spot tack on the outside corners where top deck material is sewn to the side quarters. (Illus. A) Now go to the front trim rail and pull the top forward and down, so the side quarters fall in place will fall in line with the roof rail. Just spot tack to the front trim rail at the corners.

Roll up the windows and open and close the doors. If the windows catch the top, or if the top binds at the doors, untack the top, throw it back, and build up the pads a little more. Now re-tack and check again. Tack the rear quarters first to the rear top bow, then to the rear trim rail. Don't drive the tacks all the way in until you are sure both of the quarters are in the correct position. Then drive only the tacks that hold the rear quarters on the rear top bow all the way down. Trim off any surplus from the quarters.

Illustration B

Now carefully center the rear valance and tack it down. (Illus. B) Bring the top deck material up and over the valance and tack it down so as to make a snug fit that will prevent rain seeping in.

Illustration C

Installing the frame, or U type of top Pull the top evenly toward the back of the car so point A falls into its proper place. (Illus. C) Adjust the top so that it lies smoothly. Tack the rear frame material to the rear top bow. Now go to the front trim rail and pull the top forward and down so the side quarters fall in line with the side roof rail. At this point, just spot tack to the front trim rail at the corners.

Roll up the windows and open and close the doors. If the windows catch the top, or if the top binds when you open the doors, untack the top, throw it back, and build up the pads a little. Now re-tack and check everything again. If you are satisfied with the top's alignment, go around to the rear trim rail.

Illustration D

Make sure the rear top bow is still in the correct position, then drive home only those tacks which hold the frame material to the rear top bow. (Illus. D) Now bring the deck material up and over the frame material and tack it to the rear top bow.

Tack the front trim rail Take out the spot tacks you put in the front trim rail, then pull the top material forward and down over the front trim rail and make it smooth and even on each side. Now begin tacking at the front corners while pulling the fabric down over the edge of the trim rail. Don't tack from one side of the car across to the other. Instead, alternate back and forth from side to side doing small, equal segments until the top is completely tacked into place, but don't drive the tacks all the way home.

Illustration E

Shape the corners (Illus. E) Cut the excess material from the trim rail in a straight line about 1/4" below the tacks along the top edge of the single cord welt so that no material extends over the edge. Now cut along the binding edge of the top material. You will see that this makes a V shaped piece of excess material. (Illus. F) Cut out the V. Grasp the excess binding and pull it forward. Now bring the binding around and tack it down to the trim rail.

Illus. F

Install the weatherstrip

Next, secure the side quarter flaps. (These are the small flaps that are usually about 2" wide and 10" long and are sewn into the side of the top.) They fit between the side roof rail and the metal retainer you removed previously. Next, pull the side quarter flaps around the side roof rail and attach the flaps. Screw into place the metal retainer, or weatherstrip channel. Now install the weatherstrip.

Now stand back and take a few minutes to inspect the job. If you installed a fabric top, don't be concerned about small wrinkles in the fabric, as they will pull out when you wet the top a couple of times. If you've installed a vinyl top, the sun will pull the wrinkles out. But if certain areas of the top are crooked or uneven, pull out the tacks in that area, adjust the material and re-tack. When you are completely satisfied with your new top's appearance go around and drive all of your tacks flush.

Illus. G

Add the trim welt Some form of double wire-on trim welt is usually used to cover the tacks and finish the job on most older classics. It usually comes in rolls and has wire sewn into it to keep it straight. The beading along the top of it is usually larger and flatter, while the bottom beading is usually round. (Illus. G)

Illus. H

Tack the double wire-on trim welt to the front and rear trim rails and the rear top bow if your car's top is the frame, or U type. Tack it flat against the car so you can see the wire, and with the small, round beading on the bottom. Your tacks should be placed no more than 4" above the round beading. Space them about 1" apart and be careful to work in a straight line so when you are finished tacking, the large, flat beading at the top will fold down evenly over your tacks. Finally, install the trim tips at the ends of the strips of double welt. (Illus. H and I)

Illus. I

Final check

Walk around the whole car and snip off any loose threads or bits of material. Now allow yourself at least half an hour to stand back and admire your job, and maybe take a few pictures. Congratulations! you've just mastered one of the more esoteric arts of auto restoration. Now you too can now pay homage to Helios in your great looking classic convertible.