I may be slow, but I am old. After 13 years I finally got to trying to address the driver side rear side awning window that never has closed all the way. This issue seems to be on nearly all the full metal body Chevy Roadtreks \.
The problem all along was that I really couldn't come up with what I would consider a good way to do the fix.
This is, after some experimenting on the fly, what I think is a decent way to fix the windows. I used it on the second side and it worked well.
The window comes out by taking out a bunch of screws around the inside perimeter, but first tape the outside of the window to the van at least 3 places across the top, one in the middle of each side, and two across the bottom. If you don't tape it it, there is a danger of it falling out when you take the screws out. It doesn't fall on it's own, but a small bump or push out when you remove the last screw could send it to the floor. Other option is to have an helper hold it it while you take out the screws. Taking off the curtains and guides and pulling the rubber inside trim strip is also necessary to do before removing the screws.
Once all the screws are out, remove the window from the outside. It may come out easily or hang up, a lot. One side of our 190 came out easily and the other hard. If it is hard to get out you may need to file the opening a bit bigger, probably in the rounded corners, which I did on one side.
Put the window glass side down on a blanket on the bench and remove the knob if you haven' already. Turn the window over and check how the glass is seated on the window seal. I think it will have a gap at the gear end just like it did in the van,only smaller.Then turn the window back over and remove the actuator rod and gear. To get the rod out, first remove the small screw in the face of the center divider metal trim right by the spring, move the spring tail out from under that same divider to release the tension with a needle nose pliers. Then remove the two screws on each end of the rod that hold it and gear and end support in the frame. Note the short screws are in the gear end. Wiggle gear end and support end toward the bottom of the window a bit and up out of the frame. Lift the rod assembly up and slide the two window moving slides out of the guide on the window glass, out the bottom of the glass. Set aside the actuator rod ass'y for now and turn window over so glass side is up. The moveable window is now unrestrained so look to see how well it seats in the seal along the non hinge bottom ends. It is highly likely that the gear end will have a not have a gap with the other end hitting the seal and it will close well on both ends. If this is the case, go back to the actuator ass'y and sight the two bars that come out of the rod. My guess is that you will find the arm that goes to actuator side would sit further away from the glass when closed and is apparent because the two rods won't be parallel.
Now you can actually change something that should do some good. Put the actuator ass'y in the vise with jaws holding at the very bottom of the rod on the support end. You are going to put a bit of force on that rod and you want it to bend without breaking the weld or deforming the rod. Site the two rods and see which way you need to bend the rod to make them parallel. Take a big Crescent wrench and put it on the top of the arm on the thin surfaces. Yes, it will unstable there but it will work OK. Here is what mine looked like at this point but after bending.
Very slowly and carefully bend the bar until it is parallel with the the other rod. It will try to twist because of the thin bar, but you can hold it straight pretty easily as long as you are aware. Once you get the bars parallel, take a tape measure and measure the distance between the bars at rod end and then at the top end. Bend the rod you have been working on to make it match the rod end measurement so the guides will easily go in to the window later.
Now do a confirmation check of the window ass'y with actuator hooked up again (reverse removal steps) to see if the window closes evenly when closed with the actuator. It likely will close tightly or very close to it, both of which are OK at this point. Take the actuator back out of the window and set it aside and turn the window glass side up. Lift up the glass to 90*/vertical and then grab it at both ends of the hinge side and wiggle it toward the bottom of the window. It should come out of the hinge and be loose but may be quite tight as they put a bit of adhesive on the ends. Set the glass aside until later.
You should now have the window with only the upper glass in it so it is lighter and easier to handle because you can use the center bar to hold it. Go to the van and put window back in place and tape 3 places across the top and in the middle of the ends, but loosely on the end tape. Go inside and put in, loosely the screws along the top edge front to rear, stopping at the rear upper corner radius as the last one. Put in the screws, loosely, down the front end side to the one above the hinge. Starting in the upper front corner snug up the screws front to rear. Then snug up the side screws top to bottom. Repeat the process in a couple of more steps until tight with a hand screwdriver. Doing this carefully is important because it seats the window frame in the van in a repeatable way and in the areas where the screws are should be able to come up tightly to van. Go outside and look at the gasket to make sure the window is tight to the van in the areas you put the screws and tightened them.
You are now to the point where the window is mounted in a way to seal the important leading and top edges to prevent leaks and is also minimally stressed and distorted in the lower window area so it should still close tightly. At this point you will get a good idea of just how much the original mounting was bending the window frame and/or the body skin. Ours on the driver side had slightly over 1/2" of gap at the rear lower corner from the window frame to the skin, not surprisingly right where the window didn't get closed all the way. At this point I put a strip of masking tape along all of the edges to write on and then measured the gap to skin every 3-4" around the frame (metal part of the frame to skin not from the compressed gasket) and wrote it on the tape at that point.
The logical thing would be to put shims between the frame and skin and tighten it down, and that does work, I tested that. But, it leaves you with a really ugly prospect of how to seal a 1/2" gap without leaks or gluing the window in so tight you can't ever get it back out. By chance I went it and looked to see how it all looked from the inside with one corner moved out that far and noticed a tapering gap between the inner and outer frames that duplicated the outside gap. I cut a couple of rubber shims at the same thickness as the outside gap and put them in between the two frames on the inside of window and snugged them up and when I put the moveable window back in temporarily, it hinged down and sealed evenly. Doing this has the huge advantage in that you can use a continuous seal on the outside with no shims in the way. Mark the shim locations and remove the window. Here is a pic of the shims in the driver side, they are big at 1/2". Two shims piled up to the right of the screw.
At this point you should be ready to put the window back for real, unless you want to do a complete cold check which I did not do. Clean the flange faces of the body where the seal will be with isopropyl alcohol and the seal on window the same. I put some Armorall on the gasket to help it not glue in too tightly, but that is your choice. I used urethane vehicle window setting rope to do the primary sealing. It is firm but pliable and can be stretched to any diameter. It took a full rope plus a smaller one to fil the big gap. I shot for 1/8" higher on the seal than the gap measured and noted on the tape. Be sure to taper the urethane to very thin where it transitions to none needed as you will get a gap otherwise, I did get one small gap. The opening is now ready to go.
Return to the window and install the glass and actuator in reverse order to taking them out but don't put in the spring screw as you will probably want the window easy to move by hand later. Carefully set the window in the frame without hitting the caulking and push in snug. Tape the top in 3 places and sides in one each side at the hinge area. Go back inside and exactly duplicate the screw install and tightening you did in the setup test to put the frame in the same position it was in then (it may be harder to tighten because it will need to compress some of the sealant). Put the shims in the inside between the frames where you had them for the test setup and put in the rest of the screws, but not tightly, just started and run mostly in. At this point check to see what the window to seal gap is with window held up just a bit so you can see if the light gap and if it is even. If it is not tighten the lower corner screws to pull in the frame to in that corner to get the opposite corner to seat. If the sealant thickness is right it may take some force to compress it. If you don't need to bring the corners in, you probably don't have enough sealant odd and need to remove the window and add some. Tweak both corner screws until the corners are the same amount open when you push the glass out a bit. The center will probably be less gap at this point so tighten the center, middle screws to pull it in tighter until the gap is the same as the ends or slightly less, not bigger at all. When you get the window fitting well start progressively tightening the rest of the screws while watching the gaps. The screws will come tight "soft" because they are not pulling tight on the body, just on the sealant so don't go too tight or you may need to add sealant. With all tight the gap should still be good and the window firmly set. Put on the knob and close the window. Go outside and see that it is well seated on the seal all along the bottom edge and corners. You should be able to push on it and not have it move if it is seated properly. If all is good the hard part is done at this point. Go inside and put the spring tail under the center bar and put in the screw to retain it.
I chose to wait a day to see if the screws compressed the seal more but if they did it did not affect the window seal, so I finished up. The inside is obvious, just put on the internal trim, curtains etc. On the outside I chose to add a layer of urethane caulking to assure a watertight seal. I used Loctite PL roof flashing urethane because it is black. Good stuff, very easy to smooth, slow curing and low shrink. I looks like almost like a continuous gasket.
Long and maybe overly detailed, and I am sure most folks will find places that they think they can find a better way. I know I would. But, I would say be sure to test to see if you get repeatable results with whatever you change. I tried multiple shortcuts and all degraded the results. The first window took me nearly 3 days to do with all the experimenting, but it allowed me to get the procedure right and the second one took about 3 hours.
Here are pix of the driver side from the front and rear. The amount the rear lower moved out is very obvious.