INSTALLATION INSTRUCTIONS PART NUMBER 172L
These installation instructions have been developed for the installation of Ashby Glare Shield Model 172L. This part number is generally applicable to the Cessna 172 model years 1964 through 1985. Refer to the STC for specific application information.
Pre-installation:
1. Protect the inside of the windshield from scratches using plastic or other suitable material.
2. Remove anything from the top of the instrument panel that is not permanently installed. Inspect the top of the instrument panel for any corrosion or damage. Repair as necessary.
3. Remove the compass from the compass mounting bracket.
4. On some model Cessna 172 aircraft there is a rubber piece running along the front of the panel that must be removed. This piece is held in by screws. If you find that one of theses screws cannot be removed without removal of the windshield, the screw holes in the rubber piece can be stretched to fit over the screw head.
5. Some of the early Cessna 172 aircraft have a small lip that was made from an extension of the top plastic bezel. Trim this lip until it is flush with the top of the instrument panel
6. Make a paper pattern from the Ashby fiberglass glare shield. Place this pattern on top of the aircraft instrument panel and locate the defroster vent on the left. (a few models have one on the right as well), as well as the vertical part of the compass bracket and the compass lighting wires. Use this paper pattern for cutting the glare shield.
7. The recommended method for trimming the fiberglass glare shield is to use an air die grinder with a thin fiberglass abrasive cutting disc. Mark the cutting line with a grease pencil. For round cuts use a standard drill bit or Unibit
8. The optimal way to attach the glareshield is to use pre-existing factory holes and screws to hold it in place. One screw on each side where the glare shield rests on the panel should be sufficient. As an alternate, you may use Rivnuts or equivalent, being careful not to damage any structure or instruments beneath the metal panel. The recommended location for attachments is shown in figure 1, though differences in individual aircraft make it very important to verify there are no underlying structures or wiring at the screw location.
Figure 1: Screw locations for Part 172 L
9. Bringing the compass wires through the hole you previously drilled into the fiberglass glare shield. Re-mount the compass.
