Window Seal Replacement

 

In real life, the gasket is smushed a lot more than depicted above.  But hopefully you get the idea. The harder the wind blows, the firmer the lips press against the glass.

When I got my 1967 Overlander almost two years ago, among the first repair parts ordered were new window weather seals because the existing ones looked so bad, and everything I had read encouraged me to “replace them now”.  But as the refurbishment got underway, I noticed that the original window seals, while seriously smushed, eroded & sometimes green with algae, were doing a fine job of keeping the rain out while more serious refurbishment issues were addressed.  In fact, by the time we made our first camping trip, only three of the Airstream’s seven windows had been resealed.  And since it rained on us while in transit on that first trip, and no water got inside, resealing the remaining windows dropped real low on the priority list.

But between being tired of looking at the old seals’ appearance, and developing a fear that the smushed seals may freeze to the windows with a possible chance of breaking one of them should I need to move the Overlander while it is frozen, I decided to finish the effort.  Below is the original factory seal;  If you look closely, you will see that it is a double-lipped seal like the graphic above indicates.

While I am sure there are many ways to remove the old seal, I found running a box cutter’s blade between the seal & the frame to work well.  Do it right, and the entire seal can be removed intact which makes measuring the new one easier.  After that, a putty knife works well to remove the gasket’s remains.  The [yellow] glue, however, does not scrape up very easily.

I read where someone suggested using a wire brush to clean the frame in preparation for new seals.  I found it to be a bust as the friction generated by the brush (I tried a variety of grits & shapes) heated up the remaining glue and made it re-stick with a vengeance.

After the bulk of the gasket was removed, acetone cleaned the remaining adhesive with minimal effort.  The wire brush was, however, handy for smoothing the aluminum window frame where it had pitted.

The seal material is sold by the foot.  When cutting to fit, make sure to cut it an inch or two too long as it will be trimmed to exact fit as the installation ends.  If it comes all wadded up, you may want to lay it out straight in the sun to let it un-kink/un-twist.

Don’t go overboard when buying your adhesive.  I mail-ordered mine, and the vendor recommended four tubes of the stuff.  The tube below had done three of my seven windows when this picture was taken.  I have since completed my resealing task, and found that one tube was sufficient.

Replacing seals is not that tough, but you need to pay attention to the old seal’s features, if there are any, around the hinge.  The Type II windows on my ’67 do not come off (at least not easily!), and the gasket must be trimmed to accommodate the added glass bar’s added thickness.  The original seal, trimmed of it’s lips, is pictured below:

Interestingly, on one side of one of my windows, the seal stopped at the glass bar, and the space was filled with silicone rubber.  Go figure.  But it did not leak.

The 3M Super Weatherstrip Adhesive has instructions for use on the side of the tube.  Basically, apply a thin coat of adhesive to both surfaces, allow to dry, apply another thin coat to one surface only, and assemble immediately.  When my other three windows were done, I skipped the “apply another thin coat” step per the advice of something I read on the Internet.  Either way appears to work fine, but I do feel more comfortable with the extra step.

Applying the glue can get messy, so feel free to wear latex gloves.  I prefer to dance on the edge of getting chemical poisoning, so I just clean my fingers when acetone when necessary.  You have to work quick because the adhesive dries fast, especially on a warm day.  Do not squeeze out too much at once or it will skin over & be unspreadable.  I find squeezing the tube with my left hand, and immediately spreading the glue with my right index finger to work well.  Be sure to practice on scrap.

The picture below shows one seal with glue applied drying.  Be sure to arrange the seal so that the area with the glue applied is not touching anything.

To apply the seal, start at one of the top corners, and slowly set the seal in position.  Before you have to turn a corner, go back and firmly press the seal against the frame.  When you are within three or four inches of the other top corner, trim the seal for both length & the glass bar before proceeding.

When attaching the seal to the window frame, be careful to not stretch the seal as the added tension could cause the seal to pull away from the corners.  Align the seal as close to inboard edge as possible. And, most importantly, make sure the lips are facing out (take another look at the opening graphic, if necessary, before starting).

When done, keep an eye on where the seal had to turn the corners as it will want to pull away from the frame until the adhesive dries.  This is due to the way the seal is being required to bend with respect to it’s shape.  If you are doing several windows at once, you may want to keep a mild spring clamp or equivalent on the corners.  Once the windows are closed, the issue goes away.

The next step involves the use of silicone spray.  Regular use (my owner’s manual indicates yearly) will keep the seals soft & pliable.  Silicone spray is required after installing new seals or the glass will grip against it when being closed, and dislodge the seal since the new rubber has not had a chance to conform to the ‘closed’ position.  However, the timing of it’s use is somewhat subjective.  Some Airstream authorities recommend letting the adhesive dry for many hours or even overnight before spraying the seals.  Two problems – 1) Unless watched closely, the seal could pull up from the corners during that time.  2) Comfort level/weather report with leaving the windows open.

I allowed the adhesive to dry for around an hour, total.  15 minutes after the corner bend looked like it was going to stay put, the seal was sprayed, and the window cranked down.  Pay close attention to the corners as the lips will not necessarily want to lay flat.  At an appropriate point during the window being closed, slide a putty knife between the glass & the corners to guide the seal’s lips into the proper, “lay flat” orientation.  Do not worry about the excess silicone spray running down the side of your Airstream.  It will not hurt anything other than leaving a shiny trail behind it.

My seals came from an Airstream dealership, so I assume it was the best possible replacement material for my original seals.  However, even after installing the seal as far inboard as possible, the ends of the lips still protrude outside the glass more than I would aesthetically like:

Among the spare parts that came with my Airstream was 10 or 15 feet of window seal purchased in the early seventies.  In the picture below, the new seal is on the left.  Notice how much taller it is than the old seal?

It is not a big deal, but it is worth mentioning.  And, before you close the window, be sure and give the window crank & catches a shot of spray lube.  Other than yearly maintenance, I hope to be good for another 38 years!