'75 Door Gap

[Tommy F.]

The door gap on both driver & passenger doors appears reasonable on the back (striker) end, at the bottom (rocker panel), and at the top rear, near the door handle. The front gap is approx 3/16" at the bottom, and grows to over 1/2" at the top. The car has been well (ab)used, but I don't sense serious crash damage, as the nose appears to be the original, and frame rails, horns, and bumper seem ok.

All of this being said, is it possible that the nose can "droop" at the front frame horns causing this? Could body mounts 1 & 2 have been monkeyed with causing a high spot at the firewall?

Motor & Trans are going back in within a couple of weeks, and I'd sure like to get this behind me know while I can climb into the engine bay.

Thanks to all,

Happy Thanksgiving,

Tommy Flick

[Alan S.]

Re: '75 Door Gap

You may or may not have a 'droopy nose' (on your car). But, my observation has been that many original cars have a wider gap on the passenger side door, at the hinge pillar, about the top 8-10 inches. To me it looks like either the door or fender was not molded to allow an even gap ,top to bottom. I think many cars have this area massaged when the car is painted.
Regards,
Alan

[Alan S.]

Re: '75 Door Gap

You may or may not have a 'droopy nose' (on your car). But, my observation has been that many original cars have a wider gap on the passenger side door, at the hinge pillar, about the top 8-10 inches. To me it looks like either the door or fender was not molded to allow an even gap ,top to bottom. I think many cars have this area massaged when the car is painted.
Regards,
Alan

[Chuck S.]

Re: '75 Door Gap

Inspect under the front end near the radiator support...early C3 cars have a front cross member that bolts to the frame horns and it supports the core support. The entire front end on the early C3s is supported at this point through the core support which is attached to the inner fenders. If your 75 is the same, and that front cross member, core support and attachment to the inner fenders is all solid, it's unlikely that "drooping" is the cause of the gap.

Try moving the front cross member area and front body up and down...if it's all "grunt solid" with no perceptable movement, your door gap has likely been like that since Day One. As Alan said, that gap is easily "adjusted" by building up the fender side with resin and mat, but be advised, when the door is opened even the spec gap quickly shrinks to near zero. Get the gap too narrow, and you'll jerk a big chip out of the door skin the first time you open the door.

Since you have panels of the later SMC, or some intermediate material, you will need to use Lord Fusor or equal filler material with reinforcement mesh to build up your front fender at the gap line. Any soul searching sessions about altering the originality of the car is left to the owner, but I would personally look at it as belatedly meeting the "spec" GM intended for the door gap...but, then, I'm a heretic.

[Chuck S.]

Re: '75 Door Gap

Inspect under the front end near the radiator support...early C3 cars have a front cross member that bolts to the frame horns and it supports the core support. The entire front end on the early C3s is supported at this point through the core support which is attached to the inner fenders. If your 75 is the same, and that front cross member, core support and attachment to the inner fenders is all solid, it's unlikely that "drooping" is the cause of the gap.

Try moving the front cross member area and front body up and down...if it's all "grunt solid" with no perceptable movement, your door gap has likely been like that since Day One. As Alan said, that gap is easily "adjusted" by building up the fender side with resin and mat, but be advised, when the door is opened even the spec gap quickly shrinks to near zero. Get the gap too narrow, and you'll jerk a big chip out of the door skin the first time you open the door.

Since you have panels of the later SMC, or some intermediate material, you will need to use Lord Fusor or equal filler material with reinforcement mesh to build up your front fender at the gap line. Any soul searching sessions about altering the originality of the car is left to the owner, but I would personally look at it as belatedly meeting the "spec" GM intended for the door gap...but, then, I'm a heretic.

[Tommy F.]

Re: '75 Door Gap

Thanks to Alan and Chuck.

I haven't tugged on the front end yet, but the core support is pretty well gone ( I have a new one in the wings )...I'll just verify that the new core support is in and snug, and maybe fiddle with door alignment some, then re-examine the gap and decide.

At my age, a droopy nose ain't the worst thing that can happen!

Happy Thanksgiving,

Tommy

[Tommy F.]

Re: '75 Door Gap

Thanks to Alan and Chuck.

I haven't tugged on the front end yet, but the core support is pretty well gone ( I have a new one in the wings )...I'll just verify that the new core support is in and snug, and maybe fiddle with door alignment some, then re-examine the gap and decide.

At my age, a droopy nose ain't the worst thing that can happen!

Happy Thanksgiving,

Tommy

[Chuck S.]

Re: '75 Door Gap

You can also adjust the door gap by removing shims at body mounts 1 and 2, but you should think about this before you go this route...Has the body ever been removed from the chassis? Is it possible the body mount shims have been altered from the factory configuration? I suppose it is also possible that the factory missed the exact shim count.

In my opinion, the fender to firewall bond would have to be broken for the nose to sag enough to open up the door gap that much...that's why I suggested trying to move the nose up/down. If the fender/firewall bond is broken, I would expect some slight movement of the fender relative to the cowl when you attempt to move the front end.

You COULD have broken bonding or other damage causing the gap to open up, but I highly doubt it. I cantilevered my front end totally unsupported for years before I finally wised up and had that "What was I thinking!" moment. I'm not SURE my front end was unscathed by the experience, but I can find no DEFINITE evidence of damage.

[Chuck S.]

Re: '75 Door Gap

You can also adjust the door gap by removing shims at body mounts 1 and 2, but you should think about this before you go this route...Has the body ever been removed from the chassis? Is it possible the body mount shims have been altered from the factory configuration? I suppose it is also possible that the factory missed the exact shim count.

In my opinion, the fender to firewall bond would have to be broken for the nose to sag enough to open up the door gap that much...that's why I suggested trying to move the nose up/down. If the fender/firewall bond is broken, I would expect some slight movement of the fender relative to the cowl when you attempt to move the front end.

You COULD have broken bonding or other damage causing the gap to open up, but I highly doubt it. I cantilevered my front end totally unsupported for years before I finally wised up and had that "What was I thinking!" moment. I'm not SURE my front end was unscathed by the experience, but I can find no DEFINITE evidence of damage.