Mark Houlahan
Brand Manager, Mustang Monthly
January 28, 2014

The ’79-’93 Fox Mustangs are no spring chickens when you think about the fact that the first year of production is closing in on 35 years old! Matter of fact, we hear fewer and fewer people calling the Fox Mustang a “late-model” since the majority are over 20 years old—the traditional cutoff date for considering a vehicle a classic. While we may not completely agree (since we still refer to our 23-year-old ’90 hatchback as a late-model), the fact of the matter is Fox Mustangs are old. There’s no softening that blow. Ask anyone who drives one on a regular basis. Popularity does not mean a car will last forever; it just means that they will always be on the road in some form or another.

Keeping your Fox Mustang in top condition is important, be it mechanical or otherwise. One area often in need of attention is the door glass run seals and belt line weatherstrips (sometimes called wipers or dew wipes). Installed into the coupe/hatchback door frame, the door glass run seals are a made of a rubber extrusion that is bonded to molded corner pieces. These seals often become rock hard from age and exposure to sunlight, eventually cracking, splitting, and separating from the molded corner section. This allows the glass to rattle in the door even when in the fully raised position. Worse, the wind noise and rain entry can make driving miserable. The belt line weatherstrips turn hard as well, but instead of causing a door glass rattle, their hard texture and loss of bonded felt backing cause the door glass to squeal in defiance as it is raised.

Tackling these two issues head on requires a bit of basic hand tool work and an afternoon of your time. While we’ve seen people cut corners when installing the run seals by cutting the forward end or forcing them into place through the glass opening, it is truly worth the extra ten minutes to completely remove the door trim panels and door speakers (if equipped) for full access to the inside of the doors. Plus, if you’re replacing the belt line weatherstrips at the same time, you need to remove the door panels regardless.

So do your Fox a favor by ordering new run seals and belt line weatherstrips from National Parts Depot, like we did, and head out to the garage for a little mechanical therapy. Your door glass will be smooth, quiet, and rattle free in no time.

1. Common issues with the Fox door soft parts include separation of the corners on the door run seal, as seen here, as well as hardened and worn belt line moldings. It is best to replace all three pieces (per door) at the same time.

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