By Roy Smalley
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This document does not take into account the difficulty with installing the assembly. There are many issues that have to be addressed supplemental to the bulletin and to the factory Workshop Manual:
As the bulletin indicates, the curvature of glass was a problem from the very beginning as the bulletin was issued in 1961.
Not only the did the curvature move the lower portion of the windshield back toward the passenger compartment, the thickness of the glass varied all over the place and still does. And the rake of the windshield will affect the adjustment of the top bows.
To be successful cosmetically and functionally, fitment of the windshield assembly (frame, rubber, windshield, cowl retainers, mirror rod, aluminum trim and holding pieces affixed to the wiper posts) must be done before the car body is painted. If the car is to have metal work on the pan or other support members the car will flex, so during the replacement of those components, using the top bows and windshield assembly is necessary to insure fit of all components, including the bows and door glass. The same holds true if any component of the windshield frame or top bows is not specific for the car or damaged, or if there is any metal work to the dash, cowl, upper fenders, and especially any unibody corrections.
If there is going to be a lot of fitting during metal repair, the bare frame can be used to rough align the body, bows (with new front seal installed!), door glass and windshield frame, so long as the windshield frame has been checked for damage, and properly assembled. (To check that, install the windshield with new perimeter seal off the car to make sure there is no binding.) During the trial fitments, everything must be bolted down as it would be when finished.... top bows, frame including mirror rod. It might be necessary to shim the base of the windshield posts, or lead the area to properly align the posts with the door glass per the bulletin. (Make sure the retainer for the mirror rod bolt under the dash has not been distorted as the rod must be tightened down to hold the frame in place)
After the metal work is completed the next step would be to install the entire assembly with new windshield, new perimeter rubber, post base seals (but not the base windshield seal) with the car on the suspension, doors latched, door glass installed. At that point, the location of the lower seal retainer (factory calls this the angular plate) can be marked and holes drilled.... that can be aided by cutting a short piece of the new bottom seal, mounting it on the bottom edge of the windshield to check how it will fit into the seal retainer at several locations. If every thing fits, the next step would be to trim and fit the lower rubber with the assembly off the car. Reinstall the assembly, double check for fit. Trimming and fitting the rubber is not easy and several removals of the windshield and frame are normal until the pieces are fitted to suit.
If the aluminum trim is new, it will have to be trimmed and discretely bent to fit, particularly where it goes between the rubber and the edge of the post on each side. Final trimming of the base seal with the windshield assembly on the car will be required for trim clearance. Even if original, some trimming might be necessary due to the curvature of the windshield and variable dimensions of the seal. Once this is done, go ahead and install the two retainers onto the wiper post to make sure they are going to fit.
If you are satisfied, remove the two retainers, unbolt the windshield frame assembly, loosen until you can pass tape between the lower seal and the cowl, and tape the assembly together over the top frame piece in several places and store the assembly in a safe place. You might want to put some padding between the tape and the lower seal to prevent distorting the seal. If you have done everything correctly, it should slide into place when the painting is finished. Dash cover on first! Be careful of paint build-up in the cowl post receiver hole.
The test of a properly installed frame is:
When installing a Roadster windshield, the key words are "No stress should be on the glass at all." If the frame doesn't fit the glass, the frame can be bent, not the glass.
— Bruce Baker