A windshield seal has a base, to be connected to windshield molding. The base is generally parallel to a windshield in a section view. A primary sealing lip is connected at an inboard end of the base, to contact the windshield. A secondary sealing lip is connected to an outboard end of the base, to contact the windshield. The primary sealing lip generally points inboard and toward the windshield and the secondary sealing lip generally points outboard and toward the windshield. An inboard leg is connected to the inboard end of the base, to be positioned outside the windshield molding, the inboard leg being generally perpendicular to the windshield. An outboard leg is connected to the outboard end of the base, to be positioned inside the windshield molding, the outboard leg being generally perpendicular to the windshield.
Steps to replace old seal
1. Buy replacement glass, either from a junk yard (there are a bunch out there) or an auto glass shop. Most shops can get it for you new, though not all of the new glass fits as well as original windshields, and it tends to be much more expensive.
2. Buy new rubber. If you are going to put the effort in, it's best to replace the seal as well.
3. Remove the old glass. Use a utility knife to slice off the outer edge of the seal, running a thin blade between the glass and the seal. Pull out the glass and chuck the old seal. As you cut away the old seal make sure not to let the widow fall out.
o Use these step as well if you are removing the glass yourself at the junkyard.
Preparing the Frame and New Glass
1. Inspect your frame. Those rubber seals, especially if they are old and cracked, can trap water against the metal frame which leads to rust.
• If the frame is seriously rusted, it is time for a trip to the body shop to get a new one cut in.
• If there is light pitting, a sanding, filling, priming and painting is in order.
• Make sure the surface, even if undamaged, is clean and smooth so the new rubber will seal well.
2. Clean both sides of the glass.
3. Put the seal on the window. This is trickier than it sounds because the new rubber is a tight fit. Find a large flat work area and put down either a rubber mat or thick cloth to keep from scratching the glass while you are working.
• Starting at one corner, begin sliding the glass into the inner groove of the seal (they make special tools to facilitate this, but a blunt screwdriver will work well if you are careful).
• A second person here is helpful to hold the seal on the glass while you work.
4. Have patience - lots and lots of patience. Remember; don't over torque the glass putting the seal in place. Doing so is a good way to end up buying more glass.
• Work slowly and make sure the rubber is well seated on the glass.
• Lubricating the glass with a little water mixed with dishwashing soap can make the rubber slide onto the glass more easily.