If your passenger or driver side window is scraping paint off the "A" pillar of your C4, the common cause is due to a broken window guiide. The following steps may help you fix the problem. When I was having the same problem, there were only two items that needed to be corrected.
1) Replace the broken Window Stop Guide (WSG), and
2) Adjust/correct the height of the Window Stop L-Bracket.
This is a catalog picture of a WSG (These guides are a side specific part, so be sure to get the correct one)
This is a picture of the L-Bracket:
Remove the door trim panel. Most everyone knows how to do this, so I can skip over the details on this. After removing the panel and disconnecting all wiring harnesses, switches, etc, this is what is revealed:
Ok, the door panel has been removed. STOP! Before your proceed any more, reconnect your window switch. Now look underneath the thin black foam insulation to reveal the molded sheet metal that covers your door's mechanicals.
There should be 8 bolts (7-13mm) that keep the sheet metal in place. Use your socket wrench and remove the bolts (marked in red in the photo below.)
Remove the metal molding. *Please note that this metal molding is not on the outside of the door panel, it is inside the door panel.
* Also, please keep in mind that your door lock mechanism is attached to this molding. When I performed this window repair, I didn't try to remove any of the small mechanical rods that were attached, I merely bent the sheet metal out from underneath the door panel to reveal all of the window mechanicals.
(Please see the following description for instructions on how to properly remove the sheet metal)
Originally Posted by Jet-Jock
“How to Remove the Sheet Metal”
A comment from Corvette enthusiast, “Jet-Jock”
“ Only thing I'd comment on is the Step 3, after removing all the bolts,
reach inside where the two plastic (white) rod guides are with a small
screwdriver and pop the rod out by pushing on the rod towards the
outside of the door. (Don't attempt to turn the guides from the side
facing you in the flat blade slot, this will break them, only remove the
guides (if necessary) once you have the rods free.)
Once the rods pop free, lift up on the accessory panel until it clears
the bottom opening. Slide it out from the bottom first. As it comes clear,
reach behind and slide the locking tab off the handle latch and lift up
on the rod to free it. Then, where the two rods connect at the rear, open
the ears of the lever with a screwdriver blade to free the one rod and lift
up on the second rod that attaches to the lock actuator.
A pair of needle nose pliers helps to pop those push type fasteners
free. When in place, they, along with the wire harnesses, help hold the
sound panel in place. Then remove the accessory mounting plate
(panel). Also, upon installation it's helpful to put either painter's tape or
masking tap over the slip nuts so they stay in position and don't rattle.”
Once you have removed the molding from inside the door, roll your window down about ½ way. When you do this, you should see the location of the WSG (highlighted in red.)
Be sure to look inside of your door panel to see if there is any debris in there.
This next picture is the broken remains of the old WSG.
Ok, it’s time to remove the old WSG. Your new (passenger side) guide should look like this (Remember, these window guides are side specific)
There is a retainer nut that secures the guide to the window, and it looks like this:
Because I didn’t have a retainer nut removal tool, I had to make good with the tools I had. Essentially, the retainer nut removal tool is needed to properly secure the retainer nut so that it doesn’t spin when you try removing the bolt. For me, a pair of vice grips did the job. Probably dumb, in hindsight, to use vice grips to secure that nut - You should always use the proper tools whenever possible.
This is the proper tool you should use:
(Notice the two protrusions at the 6 O’clock and 12 O’clock positions, which are there to prevent the retainer nut from spinning.)
Once you have removed the bolt, WSG, and retainer nut, this is what you should see.
Ok, now put on that new WSG. (The new guide should fit perfectly so that you can attach it to the window while allowing it to slide along that black vertical bar you see in the picture)
Now just put the retainer nut on the backside of the new window guide and bolt it into place (Remember, you’ll need to use the retainer nut removal tool or another tool, like vice grips, to secure that retainer nut again so it doesn’t move). Don’t overtighten!!!! SNUG is what you need! Voila! You’ve just installed your new window stop guide.
You may or may not need to proceed beyond this step if your window still doesn’t align properly when you try closing the door. I took it upon myself to go ahead and replace the old L-Bracket
(Assuming you don’t want to replace the bracket, then just put everything back together again.. disconnect window switch, reattach the sheet metal molding, foam insulation, door trim panel/pieces, reconnect window switch)
If you want to replace your old L-Bracket, proceed with Step 6.
Ok, let’s replace the L-bracket. This is a very easy step.
Let’s go back to this photo: The circled area is the bolt that holds the L-bracket in place.
Ok, now unbolt and remove the old L-bracket, and put the new one on. Keep a mental note of how the old bracket is attached. The Velcro on the new bracket should be facing away from you, and should be ‘high’ on the door. Almost think of the bracket like a Tazer gun; hold the ‘bare’ metal part in your hand, with the Velcro’ed end acting as the “barrel” of the tazer gun pointed at someone.
You may need to adjust the height of the bracket so that when you roll up the window, the top of the window glass stops evenly along its horizontal axis. If you roll up the window and the glass is still crooked/cockeyed when you try closing the door, you need to adjust the bracket height some more. Adjust the bracket until the window is no longer crooked.
Now just put everything back together again.. disconnect the window switch, reattach the sheet metal molding, foam insulation, door trim panel/pieces, reconnect window switch)
Here’s the BEFORE picture of the window:
Here’s the AFTER picture: