The REAL reason why it is so important to have tight door hinges on 3rd Gen F Body cars

Although having tight door hinges ensures that the doors close properly and will not rub against the ground effects, that is not the real reason they are so important.

The real reason is that they maintain the integrity of the body. These cars all have unibody or monocoque, if you prefer ,type construction, which is to say that they do not have frames upon which the body rests.

Body-on-frame construction was traditional for decades, but in the sixties GM and other manufacturers began construction of cars which had no frame. The body of the car itself became the frame. This method of construction, although much lighter in weight and less expensive, cannot possibly be as strong as body-on-frame construction. So any unibody car will have some flex. Some more than others.

High horse power applications of over 300hp aggravate this condition. This is one reason why GM did not introduce the 350 cubic inch engine into the F bodies until 1987. The designers cleverly made use of every component to reinforce the body, including the doors and even the windshield. The reason 3rd generation F body doors are so heavy is because they have massive reinforcements built into their construction. These reinforcements to the door are critical to the body integrity/strength.

Once the doors are closed, the door becomes a strong, solid connection between the door striker and upper door hinge. If the upper door hinge is worn out, the body, especially the cowl, area is free to move about. This movement is very small and unnoticeable at first. But eventually small cracks begin to appear in strange places. For instance, on hard top cars small cracks begin to appear in the roof, due the "oil can effect", and in all of our cars at the base of the cowl area. These small cracks at the base of the cowl are normally concealed by the factory undercoating in the front wheel wells.

The newest of ours cars is already ten years old. The oldest is over twenty years old, so some of this is to be expected. For those cars that do not yet have any cracks, they can be prevented by the installation of subframe connectors and replacing the worn door hinge pins and bushings.

If you want to test this theory, take a friend for a ride. Very slowly drive diagonally across a parking lot speed bump with both doors held open slightly. You will notice that the doors will now move relative to the body. This is even true of cars with subframe connectors, only it is to a lesser degree. In day-to-day driving the same movement occurs if your door hinges are worn, it's just that you don`t notice it. Think of it this way, the entire front of the car, along with the windshield and roof, are attached to the cowl. The only support the cowl has, is the roof and doors. In a T-top car we all know how much support the roof is (?!) That is why people who are planning to race, generally avoid the T-top cars.

All of these cars have stood up very well to hard use and abuse for between ten and twenty years, but time is taking its toll. If you are planning to keep or restore one of these cars, fix the door hinges first! While you still can! In the long run it is a relatively inexepensive and simple repair. If you are planning on a new paint job, repair the door hinges first. It will be well worth the time and effort.

Wouldn't it be great to have your doors close just like they did when they left the factory?

Those of you who do not feel that your door hinges need repair, go out to your car, open the doors about a foot, and firmly lift up at the rear of the door. That movement is all in the door hinges! I have two friends who must get in and out of their cars from the passenger side because the drivers side door hinge is so worn out.