Such soft parts as weatherstripping, window channels, door rubbers and grommets, windshield and backlite gaskets, trunk lid seals, and hood weatherstrips are items we can’t imagine doing without. Yet if you look at most Mustangs on the road today, you’ll notice that most of them need new soft parts. Slam their doors and the windows rattle. Open the decklid and you’ll find chipped paint because the seal has hardened. A wash job makes the carpet soggy because the door weatherstrips or windshield/backlite gaskets have become brittle and ineffective.
Our point? Soft parts are more important than you realize. What’s more, proper installation is just as important as the need for replacement. We want to show you where these soft parts are and how to replace them with the best results possible. We’ll show you with photos and illustrations that will give you insight into all of your Mustang’s important soft parts.
Windshields and Backlites
Certainly, a frustrating point for most of us who restore Mustangs are leaking windshields and backlites. We’ve visited with a lot of auto glass installation professionals, and no two have the same routine for leakproof windshield and backlite installation. So we looked to Father Ford on this one because we want to understand how Ford managed a leakproof installation to begin with.
The Right Stuff
Whenever you’re installing classic Mustang window glass, it’s important to remember to use the correct sealer. Because classic Mustangs have window grommets or gaskets, they use a different type of sealer from the sealer used on late-models. Because gasket-type windshields and backlites are becoming very old news, a lot of windshield shops don’t carry butyl sealers anymore. They use 3M’s Windo-Weld—sometimes in error—on classic Mustang windshields. Problem is, Windo-Weld is an adhesive and is used for gluing glue-in windshields into place, so it has no place on gasket-type windshields. Windshield adhesives make the windshield virtually impossible to remove, should it ever need replacement in the future.
Remember, always use a butyl (rubber/petroleum-based) flexible sealer on your classic Mustang windshields and backlites. If your windshield shop suggests gluing in your windshield instead of using the rubber gasket, find another windshield shop.
Felts, Rubbers, and Channels
Classic Mustangs used two basic types of soft parts for doors and windows: molded rubber and felt. Between the door and the body, Ford used molded air-foam rubber weatherstripping. This weatherstrip is retained with 3M Super Weatherstrip Adhesive, available from most autobody paint and supply stores. Run a thin film of this adhesive on the weatherstrip and on the body. Allow it to skin over for 20-30 minutes, then lay down a thin film of this sealer again on the body, and install the weatherstrip. The adhesion will be permanent.
Window channels guide the window up and down in the track. In order to access the channels, you must remove the door panel. For the ’65-’66 model years, the channel and window track are one. For the ’67-’68, the window channel is installed in the steel window track. In any case, your objective should be a smooth operation. For the ’65-’66, the window channel assembly slips into the vent-window frame, with the grommet at the top held in place with a single rivet. For the ’67-’68, the soft channel is retained at the top of the track with a single-sheet metal screw.
Window felts and slippers are retained with clips externally and internally, except at the rear quarter windows—where they’re retained internally with staples. The greatest challenge is to ensure the window does not remove the slippers and/or felts during roll down. This is where proper window adjustment is vital.
Other Seals
Both the hood and the decklid have seals as well. Decklid seals should be installed using 3M’s Super Weatherstrip Adhesive as explained earlier. The seal’s mouth (groove) should be pointed inward, never outward. It should be attached to the lid, not the body. The seal’s end gap should always be positioned at the trunk lock, never at the backlite. These suggestions are based on experience and knowing how the factory did it to begin with.