Valvoline.com

Sunroof Rebuild

Replace the seal between the body and the glass

How do you rebuild a sunroof? It's much like any other mechanical part of your car with moving and non-moving parts—maintain or die.

The working parts of a sunroof include the manual hinge (in the case of our '92 Mustang GT) and its subsystems, the tongue-and-receiver forward locators and the roof seal itself.

Starting Point

Start with one of the three main parts of the sunroof. We began with the least complicated element, the front-edge locator tangs. These are metal, plastic-coated and secured with large (#3) Phillips bolts into receiving fasteners that terminate on the outside of the sunroof. We applied heavy but gentle torque and they eventually relented.

The plastic coating on the tangs was in good shape, so we chose not to replace them. Instead, we cleaned up the hole into which they mount, chasing the threads of both nut and bolt. We then added Loctite to the threads and sealed the hole with a butyl-based caulk to prevent water leakage. You won't need much of the sealer because if you apply too much you'll be cleaning it off of the glass, inside and out, and it's a bear to remove. Silicone-based caulks would likely work too, but for us, it was in scarce supply. As for the female body inlet that inserts into the metal tongue, examine and verify their condition. In this case, they're rust-free, not brittle or cracked and sealed (again patchable with a little butyl).

Hinge and Keeper

Next on our list was the main sunroof actuator hinge and keeper, a combination of body latch, release mechanism and manual opener, located in the middle of the sunroof's inner-rear edge. Here was the second reason for the rebuild. This latch, which was anchored to the sunroof with two through-bolts much like those on the forward locator tangs, had developed a leak. The plastic bolt cap which spanned both through-bolt holes on the sunroof’s exterior was suspect. It had weathered a little and possibly pulled from its factory-sealed position.

We stripped this hinge from the sunroof, starting with the recessed Allen-key bolts, which keep the main hinge from moving in its receiver. These hex-head screws had loosened with time, and that movement allowed the hinge to rattle and shift, another thing we needed to repair. The actuator hinge came free from the sunroof body once the Allen screws and then the larger Phillips-headed bolts were removed. We again cleaned and chased the parts, replaced them and sealed the through-sunroof openings with butyl-based sealer, applied Loctite to everything threaded and made sure not to overtighten the latch. A proper set-height and smooth action was necessary for optimal sunroof operation.

Weatherstripping

The number one reason for our sunroof rebuild was the condition of the main weatherstripping. This acts as a surround for the entire glass surface and seals the sunroof to the Mustang's body. With age (the car's got 155,000 or so miles on it), the liner dried out, becoming brittle and cracked throughout its exposed surfaces. Water got in and began to puddle in the corners of the sunroof indentation in the roof—a sure invitation for rust. Examination of the roof-panel weatherstrip showed it to be in good condition (flexible, rubbery, not discolored), so we concentrated on the sunroof seal.

The seal was the one part of the sunroof we couldn't repair so we called Sacramento Mustang (sacramento-mustang.com) and ordered an exact OEM replacement. Removal of the old weatherstripping was like peeling an orange (the gasket, being a metal-backed felt-rubber sort of thing shaped like an inverted "F," was held in place by the two lateral prongs of the "F")—it came off the glass body in one piece. Installation of the new weatherstrip was the direct opposite. We realized the leading end of the seal has to be in its final position at the beginning of the process—you can't maneuver it once it's in place. This proved to be one of those installs you initially dread, but upon performing the process everything falls right into place.

With all four of the individual parts rebuilt, we test-fitted the sunroof. As planned, there was a bit of tension between the new gasket and the Mustang's roofline, but this is a sign of good fit. As long as the hinge is perfectly tight—not so stiff you can't close the sunroof, but snug enough that there's a tight seal that is level with the roofline and doesn't rattle—that firm seal-to-roof fit is just what you want.