This Article will focus on replacing single pane broken glass in an aluminum sliding glass door. If your sliding door was installed before 1980, there is a possibility that the glass is not safety glass. The law requiring safety glass in all doors was passed in either the late 1960's or early 1970's. In any event, it really doesn't matter. What does matter is that you must install safety glass when replacing the broken glass. You can order the glass from a local glass shop. They will need to know the width, the height, and the glass thickness. If you live in a residential tract home, there are standard sizes used in the sliding door industry. For example, if you have an opening of 6' wide X 6' 8" Tall, the glass in each panel will be 34 X 76. You can confirm this by measuring across where the glass disappears into the frame rail. You should come up with somewhere around 33". That means the glass goes approximately 1/2" into the frame on each side. The height will measure approximately 75". If You have a small 5' wide door, the glass will be 28 X 76, a 7' door will be 40 X 76, and an 8' door will be 46 X 76.
Exceptions to this rule will be in mobile homes, and in some rare cases, custom built homes. If you measure the old glass and come up with 33 X 72, then you need to order 34 X 73. You will find that most glass shops stock the typical sizes, but if you require something custom, they will have to order it for you, and it could take a few days to get it. You need to know the thickness as well, especially if your door is newer than 1980, and the broken glass is tempered safety glass. The typical glass thickness in doors made before the tempered law was 1/4". I have seen rare occasions where 3/16 was used. But, when the tempered glass became mandatory, the manufacturers wanted to save money, so they made frames that would accept 1/8" glass and 3/16" glass. They stopped manufacturing doors with 1/4" tempered glass. It's very simple to determine the thickness if the broken glass is tempered, because you will have thousands of tiny pieces all over the floor. Just measure the thickness of one of those pieces. However, if the glass is not tempered, and if it's only cracked, it takes a bit more effort.
Go to the hardware store and buy a cheap glass cutter with a wood handle. They cost a couple of dollars. Scratch the glass with it from the existing crack to the frame where the glass disappears. make the cut to the same frame rail where the existing crack goes, because the object is to separate this piece from the rest. After scratching the glass, go on the other side and tap the scratch with a screwdriver handle. So, if you scratched it from inside the house, tap it from outside, and vise versa. The glass will "run" towards the frame. Keep tapping right behind the "run" as it goes along. Once it reaches the frame edge, you should have two cracks going to the edge, thus isolating that piece from the rest. Now, tap the point where the two cracks meet until the edge of the glass is exposed. Measure it, then duct tape it really well until you are ready to replace it.
When you order the proper width, height, and glass thickness from the local glass shop, be sure to tell them it must be tempered glass. As I said, in some cases you will be able to pick up the glass same day, other times it will take days to get it. In either case, once the new glass is at the house, it's time to swap them out. 95% of all sliding doors have the fixed panel on the outer track and the slider on the inner track, so we will assume that is what you have. If the broken glass is in the fixed panel, the job is easier, so let's start there.
Remove the screen door if you have one, then look at the bottom track, where the fixed panel stops. There is supposed to be a piece of metal running from the bottom corner of the fixed panel over to the side jamb that the slider locks into. That metal piece has two functions. First, it is designed to keep intruders from prying out the fixed panel, and second, it acts as a threshold. If you don't have one, don't worry about it. To remove it, try to get a tool into the crack where the piece meets the side jamb, and pry up. If the crack is too small, use a flat screwdriver and tap it with a hammer where the outer edge of the metal piece is snapped into the bottom track, and once again, pry up.
Once that is removed, go inside and look for screws where the fixed panel frame goes into the side jamb. Remove any screws. There are usually 3 of them, one on top and bottom, and one near the center. If you don't see any screws, look outside where the top and bottom corners of the fixed panel go into the top header and bottom track. They sometimes use a metal clip and screw to hold the fixed panel in place. Once all screws are removed, grab the fixed panel rail near the bottom corner, and lift straight up. This loosens the frame. You should then be able to push it back down and work it out of the side jamb. Once it's away from the jamb, you should be able to grab both side rails and lift the panel up and out of the bottom track, then pull it out of the top header. Remember how it goes back in, so you don't put it in wrong.
Try to find a table that you can lay the panel on and have one long and one short side hanging over the edge. Before laying it on the table, put an old sheet down, because glass is going to fall out when you pull the frame apart. Ok, lay the frame on the table, and remove two screws from opposite corners of the frame. In other words, if you remove the top right corner screw, remove the bottom left screw. Then remove the rubber edge piece that goes all the way around the glass. Clean all of the broken glass pieces out of the rubber. You can wear a glove and run your finger through the rubber channel to be sure all the glass is gone. You now have a piece of rubber and two L-Shaped frames.
Clean off the table, and lay the new glass on the table, with one long and one short side hanging off the edge. Install the rubber on those two sides only, then take one of your L-Shaped frame pieces (it doesn't matter which one), line it up with the edge of the glass, and tap the frame onto the rubber, starting at the corner and doing the short side, then the long side. You can tap it with a rubber mallet or the wood handle of a hammer. Slide the glass so the other 2 sides hang off the table, then install the rubber again and tap on the second frame piece. Install the screws back in the corners, and install the panel back into the opening.
If your broken glass is in the slider, you still have to remove the fixed panel from the opening. The slider will not come out from inside the room. The inside lip on the bottom track is too tall. Take a phillips screwdriver and locate holes at the bottom corners of the sliding door panel. These holes allow you to raise or lower the rollers underneath. You need to adjust the rollers all the way in order for the door panel to lift out of the bottom track. Turning counterclockwise will accomplish this. You may even need to have someone prying on the bottom of the frame while you try to lift and pull the bottom out.
The procedure for installing the new glass is the same as for the fixed panel, except you will have to remove the handle and lock assembly before you can take the two frame pieces apart. Now might also be a good time to replace your rollers. Many hardware stores carry the most common types of rollers, but if you can't find them, you might have to go back to the glass shop that sold you the glass. Bring them a roller and if they don't have it in stock, they can usually order them for you. When you put the new rollers in, adjust them all the way so the door will lift over the track easily, then after it is installed, you can adjust the rollers clockwise until the door slides smooth and level, and locks easily.