Resealing Quarter Windows
A major cause of rust in the hatch area of many 300zx's is leaky quarter windows and taillamps. The telltale sign of seal failure in these areas is water and or rust under the hatch carpeting, namely in the spare tire well and under the tool kit. This is the approach I used to remedy these leaks.
Checking for leaks
To verify that either the quarter windows or the taillamps are the culprit, remove all rear interior plastics and lay in the back of the hatch area. Have someone spray the quarter windows and taillamps, near their top surfaces. If you observe any water leaking into the car, mop it up and replace the failed seal.
Removing the Windows
Begin by removing the quarter windows; the quarter windows are held in by two nuts and sealed using butyl rope sealant. Park the car in direct sunlight until it is hot to the touch. Remove the upper plastic interior hatch trim (quarter window trim). Be careful as the top clips like to break.
Now find the two bolts securing the quarter windows in place. Use a 10 mm wrench to remove the nuts and gently push out on the window to break the butyl seal. From outside the vehicle, carefully pull the window away from the car and sit it aside. Use mineral spirits to remove the butyl sealant from the quarter panel and quarter window.
With the quarter windows out, turn your attention to the taillamps. Remove the rear term plastic and locate the taillamp mounting nuts. Remove these nuts and carefully push the taillamp outward. Each taillamp is sealed in the same manner as the quarter windows and will come out in like fashion. Carefully clean all butyl from the taillamps and chassis using mineral spirits.
Note:If you use a scraper to help remove the butyl, be careful not to scratch the surface. Scratches will lead to rust and eventually, to leaks.
Go to your local Autozone and purchase 4 packages of butyl Ribbon Sealant.
Carefully measure the amount of butyl rope needed and cut to length. Press into the quarter window channel on the car and knead the ends together to form a continuous bead.
Finally, reinstall the window and tighten the nuts. Don't go super tight with the nuts as you could damage the trim pieces.
Taillamp resealing should progress in like manner
Sources Used on This Page: Writen by: Redare