Door window glass alignment

[Triv]

Hello all. Hoping someone can offer me some insight. I tried searching both the site and the internet, but could not find any useful info.

Anyway, I bought an '86 Silverado about a year ago and have been working through a ton of stupid little repairs. Last week was a tear down of the steering column. Finally got my horn working, blinkers working properly, and got a new ignition cylinder installed. I'm finally getting around to the windows. My issue is that both the driver and passenger windows, which are manual, fall out of the track when they are rolled down. I need to physically slide the piece of glass over and get it in the track to put the windows up. I have the door panels off and don't see anything jumping out at me. The tracks are all connected, the regulator seems to be doing its job, and there are no loose parts in the bottom of the doors. I do not believe they are the original doors to the truck, and it is obvious that someone has been in there before. Maybe parts are missing, or just worn out, but I can't seem to find what the actual cause of the problem.

Any information would be appreciated. Thanks.

 

[bluex]

The piece labeled #9 in this drawing is what you use to set the window in place. Push the window all the way forward and then loosen the screw on this guide and push it into the window as well. It should stop falling out after that. It is also possible that the tack weld holding this guide to the lower mounting bracket is broken. That can allow the guide to come off the bracket and then the window falls out next time you roll it down.

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[chengny]

My issue is that both the driver and passenger windows, which are manual, fall out of the track when they are rolled down. I need to physically slide the piece of glass over and get it in the track to put the windows up. I have the door panels off and don't see anything jumping out at me. The tracks are all connected, the regulator seems to be doing its job, and there are no loose parts in the bottom of the doors. I do not believe they are the original doors to the truck, and it is obvious that someone has been in there before. Maybe parts are missing, or just worn out, but I can't seem to find what the actual cause of the problem.

Any information would be appreciated. Thanks.

Just to be sure we have this right?


When the window is in the raised position - both vertical edges of the glass are observed to be well within the slots in the forward weatherstrip (item no. 39 below) and the channel run (item no. 58). But when the glass is lowered, the glass is able to fall out of the slots. This renders the window inoperable - until you manually realign it.

I'm sure you can understand that it's pretty hard - and frankly, kind of presumptuous - for anyone to offer advice on this kind of problem without putting their hands on it. You are there, so you are in the best position to assess the situation. I would imagine that measuring the front to back dimension of the glass at the top and comparing that number to the distance between the forward and rear channel runs - at the point where the top of the glass is when rolled down - would tell you whether the correct glass is installed.

You mention this:

it is obvious that someone has been in there before.

In what way is it obvious that the door components have been repaired/modified? Other than incorrect glass being installed, the only other thing I can see as causing this issue would be if one - or both - of the channel pieces wasn't the correct application or was not properly aligned. An incorrect weatherstrip and/or run
probably wouldn't cause this - they pretty much conform to the contours of the channels.

Here are the parts list and dwgs for the door guts applicable to your truck. They might shed some light on the problem:

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[Triv]

Thank you both for the replies.

Bluex - I completely understand this theory. Problem is when the window is up, it fits perfectly within the weather-stripping, but when lowered the glass can freely slide back and forth in the sash assembly (# 35 above). It slides right out of the front weather-stripping (#39) and channel (#40). When I go to roll it back up, it gets jammed because it does not slide directly back in the track. This is where I need to physical pull the glass over and slide it back into the front weather-stripping. Once I do that, it rolls up the rest of the way without an issue.

Chengny - You are correct in your first statement. As the window goes down, the distance between channels widens, which allows the glass to pull out of the track. When I removed the panel, there was duct tape covering the access holes, and I can see yellow wax writing on one of the side tracks. Someone was definitely in there before.

The schematics are helpful. Thank you.

If the side tracks are supposed to be the same width lowered as they are up, then I know I have an issue. I am at work now, but once I get home this evening, I will explore deeper.

 

[Honky Kong jr]

There might be stuff missing from your track set up.

 

[Big Chip]

I had a similar issue with my windows. My felt runner (number 58 in the second illustration) was missing off the back track inside the door and it would allow the window to fall out of the rear. I could move the window front to back when this happened but I couldn't roll it past about halfway. I would have to remove the door panel and pop it back into place. I replaced the seal and all is good now.

 

[bluex]

Thank you both for the replies.

Bluex - I completely understand this theory. Problem is when the window is up, it fits perfectly within the weather-stripping, but when lowered the glass can freely slide back and forth in the sash assembly (# 35 above). It slides right out of the front weather-stripping (#39) and channel (#40). When I go to roll it back up, it gets jammed because it does not slide directly back in the track. This is where I need to physical pull the glass over and slide it back into the front weather-stripping. Once I do that, it rolls up the rest of the way without an issue.

I get what your saying. With the window up it has to fit snuggly as the window guide goes directly into the door itself. It simply cant be wrong. The piece I circled is in the lower part of the door an is responsible for holding the glass in position when lowered. It is adjustable an they commonly break at the weld I mentioned.

Without that properly adjusted the window is free to move out of the front window guide an it can roll around on the regulator wheels. Even if your window is loose on the shash it still shouldnt move enough to fall out with the piece I mentioned in place an correctly adjusted. I did forget to mention in my original post that you should set the position of that guide with the window down.

I had to fix my window for this very problem multiple times till I figured out what was causing it. I'm 99.875% positive this is your problem. With manual windows that's all it really can be unless your window guides are so old an brittle there isn't much left....

 

[Triv]

I get what your saying. With the window up it has to fit snuggly as the window guide goes directly into the door itself. It simply cant be wrong. The piece I circled is in the lower part of the door an is responsible for holding the glass in position when lowered. It is adjustable an they commonly break at the weld I mentioned.

Without that properly adjusted the window is free to move out of the front window guide an it can roll around on the regulator wheels. Even if your window is loose on the shash it still shouldnt move enough to fall out with the piece I mentioned in place an correctly adjusted. I did forget to mention in my original post that you should set the position of that guide with the window down.

I had to fix my window for this very problem multiple times till I figured out what was causing it. I'm 99.875% positive this is your problem. With manual windows that's all it really can be unless your window guides are so old an brittle there isn't much left....

Very much appreciated. I was briefly looked at this again last night and just couldn't figure out why it was happening. Like you said, it is very basic. I will check out what you are describing and post again with a follow up.

 

[Ron Maturo]

I get what your saying. With the window up it has to fit snuggly as the window guide goes directly into the door itself. It simply cant be wrong. The piece I circled is in the lower part of the door an is responsible for holding the glass in position when lowered. It is adjustable an they commonly break at the weld I mentioned.

Without that properly adjusted the window is free to move out of the front window guide an it can roll around on the regulator wheels. Even if your window is loose on the shash it still shouldnt move enough to fall out with the piece I mentioned in place an correctly adjusted. I did forget to mention in my original post that you should set the position of that guide with the window down.

I had to fix my window for this very problem multiple times till I figured out what was causing it. I'm 99.875% positive this is your problem. With manual windows that's all it really can be unless your window guides are so old an brittle there isn't much left....

 

[Ron Maturo]

I'm Having the same issue, Being I'm unfamiliar with C10s and the truck being new to me I have no idea if the correct parts are even the issue. I've been trying to figure out how to adjust the channels but dont see how being the mounting bolts have holes only large enough for them. when the glass is down there's about 1 1/2" to 2" gap from the glass to the channels

 

[bluex]

If you cant get enough adjustment out of the mounting holes then its possilbe the rear sash has been bent by trying to force the window down with it out of alignment. Push it all the way forward and tighten the bolt, roll the window up and gently pull it forward to tighten the winow in the track while down. The bracket on that is fairly flimsy and can be bent back to where you need it fairly easily.

 

[Ron Maturo]

I'll give that a try, Dumb question, Why is there 2 part # 73-80 81-87? I called lmc they didn't know what the difference was.

 

[bluex]

The glass is thinner on 81+ I believe.

 

[Ron Maturo]

I wanted to say thanks, With your help I found the issue, the rear channel was bolted to the door in the wrong spot too far rearward. I figured out the correct placement and it works good now! Thanks again.

 

[Andreas Wickman]

Extremely helpful. Very much appreciated. I just love this site and its members. So great to be a part of it. Thank you all!