27Chevy,
I don't know if the 27 is the same as my 28 Capital 1 Ton, but basically, it is a procedure that will require some disassembly of the door. This is difficult to write, but I'll give it a try.
If you already removed the glass, then it is fairly easy.
First, if you are referring to the long felt covered metal channels (left and right), where the glass slides in, these are fastened with brass split rivets. Just remove the rivets, one at the top and one at the bottom and the channels should come loose. The new channels usually need to be trimmed and then drilled for the new split rivets and installed in reverse order.
If you are referring to the metal channel that the glass actually sits in, you will need some glass setting tape. This channel must be placed on the glass prior to assembly on to the regulator. Note: Before removing the old metal channel from the glass, mark the position on the glass, as this is important to prevent sidewards torquing of the glass when rolling up and down the window. Also, when assembling, I advise "dry" fitting everything before using the glass setting tape.
I removed all the screws that hold the wood support for the regulator, but leave the regulator mounted to the wood. The glass and channel will slide off the regulator arm. Note there is a right and left to the glass channels.
When applying the glass setting tape, form it into the channel half way and then wet it with soapy water. As the glass is pushed and positioned into the channel, the tape will wrap tight to the glass and be forced into the channel. Once dry, it will be very tight, and will not move.
I then positioned the glass into the felt channels and then slid the regulator arm onto the glass channel. By turning the regulator and sliding the window up and down, you can align the wood back into proper position to screw it back to the door.
After writing this, I see that this is much easier to do then explain! In any case, I hope it helps!
