Lip-in Installation

Posted by :Bob Beranek On : January 10, 2013

In my last post we discussed the rope-in installation. That installation is defined by the necessity of removing the glass and the gasket as a one piece assembly. The lip-in gasket installation is the removal of the glass from a gasket which stays on the vehicle’s frame. The lip-in is more problematic due to the method of removal from the reusable gasket weatherstrip and direct contact of the insertion tools to the glass edge during insertion into the gasket.

In the last post, we mentioned that all rope-in installations are with “S”-shaped gaskets. The lip-in method can be used with any gasket type, “S” or “H,” as long as the gasket design allows for that method. Some design features include, a locking insert—either black or chrome colored, or a self-locking flap. These locking designs are used to relax the gasket for easy insertion into the glass’ “U” channel of the gasket. Once in place, the locking device is re-tucked or inserted and the glass is solidly installed in the gasket.

The tool of choice for lipping the glass into the gasket is the plastic stick, although there are times where a hook tool is utilized to stretch the gasket around the glass edge near a corner. The problem with the use of a hook tool is that the metal to glass contact is possible and that could cause a fracture if care is not taken. It can also tear the gasket or cause damage to the vehicle’s paint if the hook slips. That is why the plastic stick is best for insertion.

The plastic stick is shaped the way it is because of the gasket set windshields. It is tapered on one side and flat on the other. Just like the cut out blades, the flat side of the stick is to the glass and the tapered side to the gasket. Whether you are pulling the tool towards you or pushing it away, angle the tool backwards, away from the direction of travel. This insures the least amount of drag on the tool and the gasket. It will also help if you lubricate the gasket with water or glass cleaner before beginning the installation process.

Here are the procedures for a lip-in installation:

Release or remove the locking device used to lock the glass into place.
Break the seal between the glass and the gasket with a hook tool or plastic stick. Repeat on the inside surface. The firmer the plastic stick the better it is for installation.
Go to the inside of the cab and using a tool or gloved hand push outward on one of the top corners of the glass until it is free from the gasket. This will take a considerable amount of pressure. Some techs will use their feet to start the removal process and then switch to their hands once the corner is free. If the glass was originally bonded to the gasket with urethane or an adhesive, it may be necessary to use a cold knife with a stubby blade to cut the glass free from the bond. Just insert the blade between the gasket and the glass and cut it free.
Once the glass is out, clean the glass “U” channel of debris.
Lubricate the gasket liberally with water or approved glass cleaner.
Place the lower glass edge in the gasket channel and seat it in place.
Use a plastic stick to lip the glass into the gasket channel. Work about 4-6 inches at a time. Run the stick back and forth to position the gasket lip to the glass edge. When the gasket lip falls under the glass edge, then pat down the glass slightly to position it deeper into the channel. When patting down the glass use the flat of your hand and never a closed fist or ball of your hand. This concentrates pressure and can cause breakage. Then lip the next 4-6 inches. Continue that pace around the entire glass edge. Do not insert one corner and then the opposite corner. This can cause breakage of the glass. Rather, lip in a continuous fashion around the glass.
When all sides are in, the glass will fall into the “U” channel.
Wipe away any standing lubricant and dry as much as you can.
Seal around the perimeter with the adhesive or sealant required and re-install or engage the locking device.
Once sealed, wet down the oozing sealant with water and scrape the excess from the glass with a razor blade. Then take a clean paper towel and make one swipe around the perimeter to wipe clean and dry.