Reassembling hardtop windows

October 1, 2015 | By Staff


Do you have or know where I can find information and/or diagrams on how to reassemble the windows for a ’51 Pontiac Catalina hardtop? I can only find information on sedans that, of course, have the center post. My car is a hardtop without a post. I would greatly appreciate any information you can give me.


The task of installing new glass in a hardtop is similar to any other sedan except that you have chrome channels and sashes that have to be removed and re-installed.

Start the process by removing the garnish moldings from the windows. Remove the door handles and winders next. To do that you press in evenly and gently on the door panels so you can tap out the pins holding the handles in place using an ice pick and a small hammer. Tape the pins to the handles and set them aside.

Wind the windows up and down and observe the workings of the winding mechanisms so you will be clear about where things go and how they work when you put in the new windows. Carefully mark where the regulator sashes are located on each window using a china marker before unfastening and pulling out the glass. Hardtop convertibles—as they were called in the early ’50s—have chrome frames and dividers that need to be removed from the glass without warping or kinking them, and that can be a challenge.

One way to do it is to use a single-edge razor blade to cut down around the rubber seals that hold the window in and then, using a small screwdriver, try to pull the window frame away from the glass without kinking or distorting the metal frame. You can also use a heat gun to soften the rubber in the chrome frame, but don’t get things so hot that you break the glass or discolor the chrome.

Save any small screws holding the frames together, and be sure to put them back when re-installing them.

Another, easier way to remove glass from its chrome surrounds is to pour lacquer thinner into a shallow pan and place the assembly in it to soak for an hour or so. The lacquer thinner will soften the rubber seal and the window will pull out fairly easily. But always wear leather gloves when wrestling with glass, because 60-year-old safety glass can delaminate and shatter. Also, don’t smoke around the lacquer thinner, and work in a well-ventilated area.

Have your new glass cut and dressed using the old windows as templates. Smear a little mineral oil on the glass edge and wrap the rubber seal around the glass. You can use clothespins or tape to hold it in place. The black rubber seal comes in both 1 ⁄32 and 1 ⁄16 thicknesses so make sure you get the right stuff. Smear a little mineral oil in the regulator sash and slip it on in the exact location that it was on the old window. Now install the other chrome sashes using the same technique.

Wrap rubber strip around window and secure temporarily with electrical tape.
Wrap rubber strip around window and secure temporarily with electrical tape.

Cut away excess rubber seal using a sharp utility knife, being careful not to scratch the glass.
Cut away excess rubber seal using a sharp utility knife, being careful not to scratch the glass.

Let the windows cure for an hour or two so the mineral oil can make the rub ber seals swell and hold the windows in place, and then install them in the car. Loosen the regulators a bit and adjust the mechanisms so the windows go up and down smoothly. Tighten things evenly in place and then grease the regulators with a little white grease before installing the upholstery panels and handles.

Installing the whisker moldings in the doorframes is pretty straightforward. Squirt a little urethane sealant along the backs of the moldings. Use short, tiny flathead screws to hold them in. Also, instead of trying to locate where the old holes were for the original mounting screws, drill new ones all around.

The whole window replacement process will most likely take a hobbyist the better part of a day, but if you work methodically, patiently and carefully your windows will look and function like new. Below is a place that sells the tools and supplies you may need for the job:

The Glass House

18935 Van Buren Blvd. Ste. 4 Riverside, CA 92508