The repairs shown here are for the Hehr Hall-Mark 12 (C12XX) windows used from 1961 to 1965. They were a square aluminum framed window with cranks (openers) on the sides.

To remove  the window, remove the two screws attaching the opener (from inside the trailer), crank open the opener al lthe way. From the outside lift up the window high and then slide the lifter end out the top of the channel.Here is the typical window pane we had. The corner joints were busted, the glass retainer strips were brittle, and the butyl rubber bedding was all dried out.

The first step was to reweld the corners with aluminum alloy rod. It is a process that takes time to learn. A good source of the material is Durafix or AlumiWeld. An alternative would be to have a welding shop weld it for you. Click on the image above for a close-up view.

With the pane removed, the old mastic (butyl tape) was replaced with new butyl tape from a glass repair shop. This tape is now available from Vintage Trailer Supply.

The glass was laid in place. If you have to replace the glass, it is 3/32" single pane glass. The retaining strip (glazing bead) was worked into place.

It will shrink and harden over one season, so do not stretch tight. Miter the corners snug, and place a dollop of gray silicone sealant in each corner before securing the strips in place. It available from Vintage Trailer Supply.

Flip the frame over and trim off the excessive butyl tape.

The window back in place. It is removed and installed by removing the openers, tilting up and sliding to the side. A single short machine screw in the center retains it (via a slot in the frame).

There is a 1/4" bulb seal with a 1/4" T-flange that serves as weather-stripping in the trailer window frame. Vintage Trailer Supply makes a perfect replacement.  Don't put sealant into the slot. At only 1/16th inch deep, you will never get it out, effectively ruining the slot.

Next we will talk about the window openers (cranks)