Door Alignments (Type 1)
There have been a couple of door alignment queries raised in the last few days so I thought I would resurrect a contribution a made a few years ago, for general interest. All of what appears below has been posted, by me, on VZi before, all I have done is put it together in one lump. I haven't re-read it myself, yet, so I hope it all makes sense and is of use:
Most door alignments involve what you do to the door aperture rather than anything you actually do to the door itself. At the production phase, VW basically contorted the bodyshell so that it fit the door. Once this had been done, any door could be swapped with a minimal degree of re-aligning. This is one of the reasons why there is so little information about door alignments - VW didn't see the necessity. However, the aging process plus external influences have frustrated many who want to get things back to that "clink" you used to hear when the car was new (and the window open).
The 'aging' process can attack in different ways and the first thing to do, when considering re-alignment, is to understand the problem. The most commonly reported is hinge pin wear. This is easy to identify and tricky to repair, as it involves either replacing the pin or the hinge completely. Another widely reported ailment is a rusty lower A-pillar, which would obviously result in movement under the weight of the door, causing it to drop when opened. The quality of the repair done to the lower A-pillar will determine how well you can re-align the door afterwards. This is an important point because there are many Bugs out there that can never have the doors fit properly because of the repair work done to the heater channels and pillars (both A & B). If you have to replace full rear quarter panels and heater channels, you may have to employ some of the factory type adjustments which involve stretching the door aperture diagonally with special equipment. However, I will not go there just yet!
One of the most overlooked door alignment problems are those affected by a missing, or perished, checkrod rubber buffer. When this happens, it means that the door can open too much and 'lock' the hinges. Once the hinges are locked the continuing force of the door (especially when caught by high winds) will, through leverage, twist the hinge reinforcement plate inside the A-pillar. This twisting of this plate moves the relative position of the hinge pin forward, which in turn means that the door will sit further forward in the aperture. So, if you look at the door from the side, when it is closed, you will notice a wider gap at the rear edge than at the front. Sometimes this may affect only the upper hinge, causing the door to move forward and up, so it scuffs the top of the aperture under the rain gutter. You can often tell if the hinges are locking open, by checking for chipped paint at that part of the hinge. You can also inspect the check rod, if it is there. The important thing is to make sure that when the door is swung open quickly, the two halves of the hinge must not lock together (if you see what I mean). Rusty and stiff hinges can cause the opposite effect of a faulty checkrod.
Hinge pin wear, welding repairs and checkrod failure can all be quickly identified as to whether they are contributors. The next thing to do is look at the door in its closed position. If the contour line on the door is not in line with the contour line on the rear quarter, then the striker plate is probably out of position. I say this because even if the door rides high or low, the striker plate will pull it into the position at which it is set. However, you will be able to see if the door is well centered in the aperture or not. There should be an even gap all around the door and the lower rear corner should line up with the rear quarter panel (providing any repairs to the quarter panel have been done correctly). If the gap is not even, then note where it is not.
Now, remove the striker plate and hold the door closed. This will show you the 'true' alignment of the door without the influence of the door lock. If the door is fully loaded (glass, locks etc) then the contour lines should match. An otherwise empty door (as in a new one) will ride higher by a few millimeters and look slightly tipped forward in the aperture. Gently squeezing the door to the B-pillar (through the window openings) will replicate the position as if it were loaded. If at the end of the re-alignment the door is correctly positioned without the striker plate then you will be a striker plate away from a perfectly closing door, without the need for lifting or slamming.