Q:I’ve got a problem with my 1955 Ford station wagon. The rubber around the rear windows is dried and cracked and there are no replacements available. Is there any way to soften weatherstripping that has become hard and brittle? Is there a way to fill the small cracks that have developed?
Bruce Carlisle
Via the Internet
A:This is a common problem without a very good solution. As rubber ages, it hardens and becomes brittle. The reason for this is the plasticizers, the chemicals that make rubber soft and pliable, dry up.
Recently, we ran across another rubber preservative that was suggested by a friend who is a dyed-in-the-wool hot rodder but is a closet sports car aficionado. In keeping with its Teutonic heritage, the rubber on his vintage Porsche is treated with a German product called Gummi Pflege Stift that is said to keep rubber soft and pliable and may actually soften rubber if it is not too far gone (with a name like that it just sounds like it should work).
There are also a variety of home remedies for rejuvenating hardened rubber. We’ve heard of using brake fluid, transmission fluid, and a combination of both—something we strongly discourage. On the other hand, a combination of alcohol and wintergreen oil (3 to 1) is said to work well on rubber parts that can be soaked. Of course that’s not possible in cases like your wagon’s windows.
When it comes to filling cracks in weatherstripping like yours some of the solutions are even more creative than the attempts to soften it. We’ve seen cracks in rubber filled with black shoe polish, a trick likely taken from the movieabout Burt Munro who filled the cracks in the tires of his record-setting motorcycle with shoe polish. Silicone is often recommended by some but it’s temporary at best.
Out of all the methods used to fill cracks in fixed rubber weatherstripping like that in the side windows of your wagon the two most promising are black rubber sealant and windshield urethane; both are extremely messy and hard to work. We’ve been told the best way to use either is to carefully clean out the crack with a razor blade or something similar and then cover the area around the crack with masking tape. With nothing but the crack exposed the sealant can be pushed into the crack using a gloved finger or a popsicle stick cut to the contour of the rubber.
Keep in mind, everything here are last ditch efforts to solve a problem that can only be rectified properly with new rubber. But if replacements aren’t available the only choice may come down to experimenting with some of the ideas put forth. Of course, if any readers have any additional thoughts on effective solutions to this problem we’d love to hear from you.
