How to Install Weatherstripping on a Square Body C10

Posted on May 27, 2015 by Jefferson Bryant in Paint/Body, Projects // 2 Comments

Rattling windows and wet seats after every rain really takes the fun out of owning an old truck. While it seems a little weird to say at times, the classic ’73-‘87 Chevy trucks are OLD! Rubber components like window and door rubber go through a change, from soft rubber, to hard and brittle plastic that breaks at the slightest touch, and the felt is long gone from the window sweeps. This leaves the interior of the cab vulnerable to the elements, which leads to wet seats and rusty floors. When we picked up this ’81, it was a running, driving project truck whose owners had started restoring. The problem is that like many projects, they hit a wall and lost interest. They used the truck daily for years in partially restored status, wearing out much of the work that had been done. When we got it, the seat had to dry out for a couple of days every time it rained and you would swear the windows were going to break when you shut the doors. It needed new weatherstripping in a bad way. Our first call was to LMC Truck. These guys have everything you could possibly need for a truck resto. A quick scan of the online catalog and we had the parts ordered.

For this article, we focused on sealing up the doors. The cab rubber (the gasket that runs around the door opening), window channel and anti-rattle window sweeps were replaced. The entire process took about 3 hours. Normally, you would replace the weatherstripping after the truck is painted. For this project, we decided that a dry seat is more important than a clean paint job. Besides, the door jambs had already been painted, just the rest of the truck had not. And since the weatherstripping doesn’t require adhesive, it is easily removed if it needed to be for painting. Unlike many vehicles, the C10 did not require any weatherstrip adhesive. The door opening rubber features a pinch welt that clamps around a metal lip. The window sweeps use molded-in clips and the window channel rubber locks into the channel via the molded sides. This process is very simple, but can still be tricky. By using some ingenuity, we were able to install he window channel rubber without removing the window. Read along and we will show you how.

1. The new rubber from LMC consists of the door jamb rubber, the window channel and the inner and outer window sweeps.

2. The old window sweeps deteriorated over time, only the rusted frame was left.

3. Using a pair of needlenose pliers, we popped the window sweep out of the door. The door panel uses a similar clip.

4. Most of the window channel rubber had broken, so all that was left were the pieces that fit into the glass run, inside the door. We used a nylon trim tool to break it loose from the channel.

5. Then we slid it out of the door. Sometimes this is easy, sometimes it breaks into small sections and you have dig it out from inside the door.

6. The upper channel had some bits left in place too. We found the easiest method was to squeeze it by the sides to collapse the molded edges from the door.

7. To aid in the installation of the window channel rubber, the steel channels were lubricated with some silicone spray from Justice Brothers. Don’t spray the rubber itself, that will only make the install more difficult (it will slip in your fingers).

8. This process is not very easy with the window in place. We tried, it didn’t work out to well.

9. So we popped the window out of the channel, which was really easy when the rubber is gone).

10. We slid the rubber down the door and used a square to push the rubber into the channel. This worked really well, nice and easy.

11. Flashlight in hand, the rubber snapped into the channel. You have to be careful here with device you choose, a sharp edge will dig into the rubber and ruin it.

12. The upper channel pops in, but you have to push this tab into the hole in the metal. We had to use a hook tool to get the old clip out.

13. The rear side of the channel was a little different. We got it started by sliding the rubber into the channel and down the door.

14. Once it stopped sliding, we reached into the door and pulled the rubber down the channel and into place. Once the rubber is installed, the window fits really tight. The rubber will take some time to break in.

15. We lubed up the window slides to make things easier while we were at it.

16. The inner window sweep snaps onto the door panel. These clips are little tricky to get started, but not too bad.

17. Once in place, the clips hold tight. These often get a little bent during shipping, you may need to tweak them before installation.

18. The outer sweep drops in from the top. The edge of the sweep covers the door, running a finger under it gets the look just right.

19. The door jamb rubber is covered by the inner trim. We took all of the screws loose, but did not remove the trim. The upper trim (shown) was removed, but the rest is fairly fragile and full removal is not necessary.

20. Starting in the middle, the rubber was slipped over the metal tab. The rubber is shipped about 6 inches too long, and you want the seam to end up in the middle of the bottom section, where the threshold trim will cover it.