C3 75 convertible door/window adjustment

[Ed Jennings]

I recently posted this question on the C3 Corvette forum and didn't get much in the way of useful answers. Anyone here solved this particular problem? I'm thinking of getting a glass company to try shaving the front edge of teh windows.

"Here's one for you C3 body experts. I have a 75 vert, never hit, no frame rust, nothing sinister at all that I can detect. The front door gaps are a little too wide to suite me, though on the driver's door , it's probably something I can live with. Right side, is way too wide, almost 1/2" at the top. Now it's no great trouble to loosen the hinges and move the door a bit forward. been there, done it several times. Trouble is that with the windows adjusted back as far as they will go, they are too far forward. I have even slotted the adjusting bracket a little and gotten them to go back another 1/16-1/8", but still too far forward to work properly. They also need to roll up another 1/8" or so, but of course that makes the forward edge come even further forward. I may try to post some pics to illustrate all this if it isn't clear. Any ideas? Anyone else got this problem? I looked at a 69 vert Sunday the was a real POS body wise, but the windows and doors sure fit nice. Rest of the body needed major work. Looking forward to seeing your suggestions, guys."

Note: I have looked at two other C3's, both coupes, in the past week or so that had a similar problem. Main difference is that it apparently didn't bother the owners that they couldn't shut the doors with the windows rolled up.

[Joe L.]

Re: C3 75 convertible door/window adjustment

Ed-----

I don't think that you'll solve it; it's one of the most daunting problems that one will experience on a 68-75 convertible. Besides, if you get it right, the car will likley not be original anymore. Very few of these cars came through with this adjustment right. Mine did not and most others that I've looked at were "off", too (I looked at a lot of them back in 1969 when I was unsatisfied with the fit, but wanted to see if it was "normal" before I let the dealer's "mechanics" loose on my car).

I can tell you this: if you decide to adjust it, use the procedure found in the AIM and not the one found in the service manual. They're completely different and the one in the service manual is the one least likely to do you any good or cause you anything but frustration.

[Ed Jennings]

Re: C3 75 convertible door/window adjustment

Joe,
I have adjusted on the door gaps until I've just about worn the hinges out, and I can get the doors to a point that they are "satisfactory". Trouble is with the windows. Especially on the passenger door, if I get the gap anywhere near right, the front of the window is hitting the chrome windshield trim. I have followed the instructions in the AIM, and adjusted the glass as far back in the door as it will go. No dice. I have the door adjusted back now, and the window fits ok (more or less), though it is still pretty tight on the weatherstrip. It could stand to go back another 1/16", but I already have a door gap at the top that is about a half inch. I know there are some bad door gaps that came from the factory, but this one is ridiculous. Any sugestions?

[Joe L.]

Re: C3 75 convertible door/window adjustment

Ed-----

None, whatsoever; I gave up on this a long time ago.

[Ed Jennings]

Re: C3 75 convertible door/window adjustment

I have two sort of fuzzy ideas, Joe. One is to try a door off a different car and see if it fits better, or put a new door skin on the existing door. Second is to see if the front edge of the window can be "shaved" about 3/16". Third, I guess, would be to build up the front of door/ rear of fender, but I don't really think that's a viable solution. Thoughts?

[Stephen W.]

Re: C3 75 convertible door/window adjustment

I've looked at these for years. My 71 had "acceptable" gaps but the top front of the door was very wide where it curves back and up to the top. I'm assuming this is the area your trying to close up. If you jack up the nose of the car does the gap improve? If so you can try shimming the core support. You can fix the gaps but it will no longer be original as Joe has already pointed out. Funny thing about the front door gap. You expect it to be a very poor fit and very wide at the top. Some I could look right inside the door jam. The one big plus with my 68 Coupe is perfect door gaps! Both sides. the car needs a frame due to rust but has never been hit. The gaps are so good I want to photo them now before any paintwork is done so I can show that I didn't alter them to make them better that what they were. I guess my question is why did they get it right on some but were so far off on the others?

[Ed Jennings]

Re: C3 75 convertible door/window adjustment

Corvette quality control was a little slack in the late 60's and early 70's. My rememberance from the time was a lot of complaints from new car owners concerning excessive orange peel in the paint. They ought to see the current crop of offerings from all the manufacturers. On this car, YOU CAN LITTERALY LOOK DOWN INSIDE THE JAMB ON THE RIGHT SIDE. Original or not, that ain't gonna cut it. I'm not trying to make it "perfect". Just acceptable. If I could get the right side to look like the left side, I'd be satisfied with it. Even with the huge gap on the right side, the window still could stand to be a 1/16" further back to truely function like it's supposed to.

I suspect there may be some car to car variation in the positioning of the door skin on the door frame. This may account for the differences in gaps in production. Also, the AIM mentions adjusting the gaps by grinding the panels. That could cause a LOT of variation.

[Dick W.]

Re: C3 75 convertible door/window adjustment

I'm gonna ask a dumb question. Has the body been off the frame, car ever suffered any serious collision damage, or is there a chance of frame rot? Any of the above can cause the problem you are talking about. Sometimes the adjustments that you are trying to effect can be made with addition/removal of shims on the body mounts.

Comments Wayne Womble or Bill Williamson?

[Ed Jennings]

Re: C3 75 convertible door/window adjustment

No frame off, nothing beyond a little surface rust on the frame and no evidence of collision damage. I have spoken with owners back to the early 80's who confirm my inspection conclusions. Only body work evident is the rear bumper has been replaced with a fiberglass replacement. I may try jacking under the front end to see if that closes the gap. The fenders seem to come out at the same spot on both sides, so I doubt that's the issue, but it's real easy to check. If shimmimg at the core support will help, it's certainly easy enough to do.

[Dick W.]

Re: C3 75 convertible door/window adjustment

Addition of shims at the core support will close the gap at the top of the door. Conversly removing shims will widen this gap. If you elect to go this route, start with the thin shims. A 1/16" shim over the distance from the core support to the door will make quite a bit of difference

[Ed Jennings]

Re: C3 75 convertible door/window adjustment

FWIW, I just went out and jacked up the right front corner of the car. There was no discernable movement of the gap.

[Jack H.]

Re: C3 75 convertible door/window adjustment

FWIW, remember there's a latitude of adjustment for the reveal moldings at the windshield pillar posts in addition to the adjustments of the door and side glass...

[Ed Jennings]

Re: C3 75 convertible door/window adjustment

I just got through doing the reveal moldings on the driver's side. That helped a little also. All in all, I can live with the driver's door like it is. The right door HAS to come forward a little. The gap at the front is too wide, and it's a little too narrow at the rear. If I could just get the window back a little further, all would be well.

[John H.]

Re: C3 75 convertible door/window adjustment

Ed, that's how the front of the door opening was created; after the front clip was bonded on, a large aluminum fixture was clamped in place in the door opening and a router (yes, a router) was used, with the machined front edge of the fixture as a guide, to shape the rear of the front clip to the proper contour to accept the door, which was installed in the next station. The rear edges of the front clip were designed a little long (extra material) to accommodate this routing process.

[Ed Jennings]

Re: C3 75 convertible door/window adjustment

John, was there a lot of variation in the position in which this "jig" was clamped to the door opening? Also, it seems that if the door skin were a fraction too far forward or aft on the door frame, that this would affect the gap as well, and might account for some of the variation seen car-to-car.