Problem Replacing Rear Window

Bob Grieb

Bob Grieb

Senior Member
I just finished replacing the rear window in my 1930 Pickup and it did not turn out like I had hoped.

I bought new U Channel rubber and the seal on the inside of the window looks great. The outside is a different story. The rubber is puckered and wrinkled. This was a first effort and I plan to redo it this next week.

I would appreciate any input as to what caused my problem and what I can do to improve the results on my redo.

Thanks

Bob
 
I have a 28 special coupe and a 29 CCPU that I installed the back window. I believe they are similar to a 30 pickup in that they use a rubber channel around the glass. First, you need to have the right thickness of glass. I used 3/16" tempered. Next I got together about 7 or 8 Pony style pinch clamps. I then clamped the rubber with one of the pinch clamps at one end and then really pulled the rubber tight and then put another pinch clamp on the rubber/glass. I kept doing that all the way around the perimeter of the glass. When I said "pull the rubber really hard", I mean REALLY hard. This is the way to eliminate puckers on the corners. After you get the last clamp on the rubber/glass to where you started, mark the rubber as to where to cut it off. Remove all the clamps and cut the ends of the rubber very straight so both ends mate well to get a 100% mate. Get some good quality super glue and glue the ends together. I put both ends over the glass to make sure they aligned well - I think I put some tape over the glass to keep from gluing the rubber to the glass. I let the glue dry over night, which probably wasn't necessary and then installed the rubber like I did before, stretching the rubber really tight and using clamps to hold it in place as I went. I was amazed the super glue held the ends together with the stretching. I believe I used some acetone to clean the ends before glue them together. Both my rear windows turned out very well with no puckers in the corners. Hope this helps.
Rusty Nelson
 
Hi Rusty

Thank you for the detailed response. I only wish I had asked for help before I started. The removal process required me to grind the screw heads of as the original hardware was corroded. I did not even consider stretching the rubber channel.

I appreciate your time in providing me with the process I need to employ.

Can you give me a little more information in defining a "Pinch Clamp".

I plan on revisiting the project after vacation and I will report back on the outcome.

Again - Thank You

Bob
 
When I replace gasket on the rear (Small window) side glass on a Coupe (may be similar) I place the seam of the rubber at the top so that rainwater can not leak in through the crack.

Might be "nit picky" but every little bit helps.
 
I did the rear window in my Coupe very much the same way as Rusty. To add on to what he said, in regards to a clean cut of new rubber seal, use a BRAND SPANKIN' NEW razor blade for a very straight, clean cut. Also, when stretching the rubber, heat is helpful. You don't need a heat gun (in fact I think that would be too hot) but just leave the new seal in direct sunlight for a while before installing it.

Interestingly, like Benson, I too was very conscious of where the seam went, but in my mind putting the seal at the bottom made more sense to me...I'm not sure why.

Ken
 
Thanks for all the input. I stopped today and bought the clamps l will need. I never gave a thought to stretching the rubber. My pickup had the original window and the seam was at the top. I am not looking forward to removing and replacing all the screws again. I had to grind the heads off of the screws the first time.

Bob
 
If you use some vavle lapping compound on your screwdriver tip it should help from tearing up the screw head.
 
I have one more question regarding the glueing of the rubber seal. Do I bond it in place while on the glass or do I mark it the remove to bond the seal then restretch it onto the window.

Thanks for the assistance

Bob
 
I stretched it and marked it. I then set the glass aside, sliced the seal with a razor and glued it. Once the glue was fully cured, I stretched it back around the glass and installed it.

Ken
 
Bob
Remember rubber has a memory and if the flue lets go you will have a gap
I just installed one this week and I just layed it out around the glass and cut my center line top center and installed and it fit fine. Once you get the frame screwed into it the corner puckers are gone if frame is tight.

And then I don't have the Mess of glue around the frame. Honestly there's very little of the river showing at the back window

In my opinion I would not stretch it tightly around the glass. I think you are asking for more aggravation than you need to .

Larry shepard
 
I have done this on my 31 CCPU after watching someone who had done it a few times and this was the modus operandi . Put the rubber around the glass and stretch it to a sensible amount ,mark where to cut . Get good quality "super glue" and a pair of latex type gloves. Cut the rubber square with a new blade. Pull the rubber installed on the glass and make sure there is even stretch all around the glass ,apply the glue ( with gloved hands ) to the join and hold till you are sure the connection is fully bonded. I then installed the glass with the join at the top . Been in the cab for a couple of years looks neat and no leaks .

John in weather was cancelled today Suffolk County England .
 
I finished reinstalling the rear window seal this afternoon by following the method first outlined by Rusty. I had lots of help from others on the forum that helped me clarify the process. It turned out great! I only wish I had asked for help in the beginning. I was going to wait until after bacation but my first attempt looked so bad I couldn't wait.

Thanks for all the help.

Bob
 
Just saw this post... I’m about to install my window - in a very old frame with a lot of work on it. (Rusted, bent, welded and ...well you get the idea)

To stretch or not to stretch, that is the question. I think I’ll go for moderate
Stretch.

Have to do the top too - what to start on first.

Thanks to all the Barners for the posts!!
 
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