CC Tech: 1988 Ford Mustang GT – Plastic, A Better Idea In Quarter Windows

To me, this is a new car.  My parents have owned it since 1990, and they even permitted me to drive it to school once a week when I turned 16, so it’s been a part of my life for a long time.  Mom drove it daily, summer and winter, for over a decade, with merely a set of all-season tires for support; Dad’s kept it all these years because my mom and I don’t get rid of things too easily.  I’ve been the car’s mechanic for a while now, and Dad still drives it a few hundred miles a year.  We did a cooling flush and hoses a couple years ago.  Last summer, I replaced the steering rack and rebuilt the power steering pump.  This year, I offered to repair the inoperative and loose quarter windows.  Little did I know that this was an infamous task among Fox-Body Mustang enthusiasts.

I have all the factory service manuals for my personal collection, but for this job I did something I rarely do and hopped on YouTube looking for help.  There is a very good video delineating the process, and the video’s producer pinned this comment right on top of the comments list.  In other words, I knew what I was in for, and I have nobody to blame but myself.

The Mustang convertibles of this generation were shipped to a company called Cars and Concepts in Brighton, Michigan, to have the convertible tops installed.  Rocker panel braces were added (it wasn’t enough – this thing is more willowy than my Corvair), and the rear window mechanisms were installed.  I’d say that Cars and Concepts did a decent job with the conversion, but I couldn’t get over the vibe that I was working on an old Bayliner.  There were a lot of trim screws drilled into metal that was inches away; it wasn’t the most well-engineered thing I’ve seen, and I’d guess Ford itself was to blame for that.

I didn’t take a lot of pictures as I worked because my hands were dirty and I was not in the best of moods.  Please forgive me for reusing pictures for different purposes.  First, the power window motors had both failed, but that was an easy fix (aside from removing the rear seat and all the trim).  The real problem was that important parts were made of plastic, including the fitting into which the window guide rod is attached.  Late Model Restoration sells a kit with billet replacements, and that is what I used to repair these cracked plastic originals.  (You can also see the slots in the bracket for the window’s lateral adjustment – more on that below.)

That bracket is bolted to another bracket, which is bolted to the rocker panel and provides lateral adjustment for the window.  To replace the window guide rod mount, I had to grind out three rivets and use the provided screws to attach the new piece, which was way nicer than it needed to be.  (By the way, that large metal rod is the guide rod.  The window literally slides up and down on it; not shown here is the window regulator plate, which holds the gears, motor, and arms that move the window up and down.)

These are the new parts from LMR.  The kit includes plastic bushings to keep the window tight on the window guide rod, which is literally a round peg through a square hole.  The parts fit very well in general.

All of this was relatively easy if you’ve worked on cars your whole life, although the positioning of the seat belt retractor, which had to be removed to do this job, reinforced my opinion that Ford’s engineers hate mechanics (I’ve said that about the entire Big Three many times in my life, although I feel that Ford hates them the most).  The hard part is adjusting the window.  There are three major adjustments, not including the window “fuzzies” that help steer the window as it travels up and down.  I’ve already mentioned the lower lateral adjustment, but the adjustment in the picture above controls the “tilt” of the window.  You loosen two bolts (from the bottom), and you can rock the quarter window back and forth to adjust the fore/aft gap to the front window.

The next adjustment is for “twist.”  If the window doesn’t seal against the front window, you can “twist” it so it does.  Picture a large clock, and imagine that the window is the second hand moving around an axis, and that’s the general idea behind this adjustment.  This one was particularly annoying.

After the window adjustments have all been made, it’s important to adjust the window “fuzzies” so the window doesn’t bump any metal edges as it moves through its cycle.  The passenger side one needed quite a bit of adjustment; I got the idea that it was never adjusted correctly at the factory.

Unfortunately, at one point I broke the small 1/4 inch stud that allows for the lateral adjustment of the passenger window.  Luckily, this bracket was bolted (not riveted, like everything else was) to the rocker panel, so I was able to remove it, take it home, and weld a new bolt to the bracket to act as a stud.  Aside from a really stubborn seat belt retractor Torx bolt and an obstinate upper rear seat, everything went as smoothly as you could expect.  I was, however, a bear to be around as I did this job; be prepared to be annoyed if you choose to tackle it yourself.  Also be ready to pay through the nose for labor if you’re having the job done by a professional.  It took me a couple of days to finish, and although I could probably do both sides in a day now that I’ve done it once, that’s still a big bill if charged hourly.

Everything went back together well, and I’m happy with the adjustments.

Now that the rear windows are working, Dad’s been driving around with the top down for the first time in a while.  He seems pretty happy with the outcome, but I’ll be waiting for my next task on the convertible.  It is nice to be able to repay him for the many times he’s come over to my garage to lend a helping hand, although I won’t always say that out loud as I’m struggling with another minute adjustment for window twist.