The BugShop: Project '57, pg 10
(1999)

This page last modified- 7/18/02
-- WARNING --

I ASSUME NO LIABILITY FOR THE SAFETY OR EFFECTIVENESS OF THIS MODIFICATION.

 I am not an automobile manufacturer, I do not work for the department of transportation. The modification described below carries NO warranty of effectiveness or safety.





I did this modification to my car because it had NOTHING in the way of passive restraints. These mods might not even work at all in the event of an accident. If you do something similar, don't even think about suing me if you get hurt in an accident. You do what what you want, I'll do what I want. We are both responsible for our own actions. I assume NO responsibility for the safety or effectiveness of this modification.

Well, as die-hard of a vintage preservationist as I am (with this car anyway), I knew I simply would not want to drive this car with no seat belts in it. Not just for me, but I want to be able to take my whole family out for trips on nice summer days. VW didn't put seatbelt mounting points into the Beetles until 1962. At first I wanted to be as vintage-correct as I could be. Investigating this a bit, I found out that the early 60s seatbelt were lap belts only and that the outside, front mounts were actually bolted into the floor (pan), not the base of the B-pillar like newer cars with shoulder belts. I also found out that, very oddly, even from the earliest mounts, the thread bore in the body for the belts was not a metric thread, rather a 7/16 inch "fine" thread (20 teeth per inch, "7/16-20").

While I did use 7/16-20 nuts to make the scab plates (a term for a metal plate with a hole and nut or threaded bore welded to it), I quickly realized that no setup was correct for my '57 and that I should adapt whatever was the most practical (ie.: retractable) and safe. I do still have hopes that I can remove the belts and hardware when my car is at a show and the mounting points will be pretty unnoticeable.

There are a total of 10 mounts that need to be fabricated, 4 for the back seat belts and 6 for the fronts, if 3-point shoulder belts are to be used. All but 2 of the 10 mounts are in the body of the car, only the inner two front mounts are in the tunnel of the chassis. Someone told me that to meet the DOT specs for seatbelt mounting point strength I needed 16 linear inches of weld on each mount. That would be a 4 inch square plate at each of the 10 points! But I decided to not rely on the weld of the mounts for their strength, rather to rely on the strength of the sheetmetal surrounding the mounts by placing the scab plated behind the panels everywhere I could, and using welding to hold them in place. The pictures below will show you what I mean....

Here are the .jpg files that were sent to me by readers at the aircooled VW newsgroup that I used for reference on this project. (use your browsers "back button after viewing to get back here or in Netscape, right click on the link below and select "Save link as..." to save the file to you hard disk)
 
 
  • seatblt1.jpg- A diagram with measurements showing the location of the tunnel mounts and the height of the upper B-pillar mount. [contributed by Jan Andersson]
  • seatblt2.jpg- A picture of the outside, rear mount in a '67 Beetle. Interior panel and rear seatback is in place. [contributed by "Bomber"]
  • seatblt3.jpg- A picture of the inside, rear mounts in a '67 Beetle. [contributed by "Bomber"]
  • seatblt4.jpg- Another picture of the outside, rear mount in a '67 Beetle. [contributed by "Bomber"]
Here you can see how the scab plates were made up. I cut squares from the 10 gauge plate (about $5 for big chunk of "scrap" at the sheet metal shop), drilled 1/2" holes in them (drill press, slow speed, some oil on the plate) bolted the nut in place, MIG'ed the nut onto the plate on 3 sides, then removed the bolt.

 
This is prior to starting work on the rear, center mounts. You can see that I had the scab plates made up, and had a printout of a photo that some nice participant on the newsgroup had sent me of the back of his '67. The center plates go on either side of that pressed dome in the panel. 
This is a cool picture. I took this from the inside of the car as Tom was welding on the backside. You can see that the plate is held in place on the backside for welding by a bolt and a couple of big washers. And since the whole body was freshly sandblasted, grinding prior to welding wasn't needed. The orange glow is where Tom has the torch, the blue light seen at the top of the weld on the left is where a hole had been burned through and the arc light is shining through. Tom later filled it.
This is the backside after both rear, center mounts were welded in place. 
These pictures show the outside, rear mounts. In the picture on the left, the scab plate is seen (nut welded on the backside) and the inside body panel is drilled in preparation for welding. The large hole and the four holes squarely around it were drilled for this modification. The hole that is in the upper left is the existing threaded bore for the seatback bolt, the one that the backrest hinges on. To keep the scab plate from interfering with this threaded boss on the back of the panel, a notch was ground out of the scab plate and can be seen on its left edge. When welded in place, this plate is not oriented as shown in the picture on the left, rather it is rotated about 45 degrees clockwise, so the notch aligns with the seat bolt hole.

On the right, you can see the scab plate welded in place, although this is the opposite side of the car from the picture on the left. A MIG bead is put down following the circumference of the larger hole, and MIG "pools" are done in the other 4 spots for added strength. 
These are the scab plates that were prepared for the upper B-pillar mounts. They are approximately 6 x 1.25 inches in dimension. They are laying on a printout of a graphic that Jan Andersson sent me showing the locations of the B-pillar and tunnel mounts. 
{Hope these pictures aren't too wide for your browser settings}

In this series of pictures, you can see how the B-pillars were done.

  1. The existing, bare pillar

    2.  
  2. I doctored this picture with a graphics package to show how I ultimately cut the pillars prior to welding. The red lines show where cuts were made (using the Dremel with those thin carbide discs), the light blue area where metal was removed. The two, shallow "tabs" left on the right and left were then bent outward to make the opening wide enough to slip the scab plate into. The upper, center tab was then hammered inward to allow the nut on the back of the plate to clear the opening as you slipped it in, diagonally, from above.

    3.  
  3. The way I kept the plate from slipping all the way down the B-pillar was to tie a piece of MIG wire to it (although it looked like it would have just fallen into the opening behind the rear interior panel if dropped). I later unwrapped the wire from around the pillar as it is shown here and used it to hold the plate in place while Tom tacked it in a few places with the MIG. I wrapped the end around a screwdriver and just pulled real hard until a tack or two was made. Note that the left and right "tabs" are still bent outward, but the upper one has been pulled back outward with a screwdriver.

    4.  
  4. This is after Tom welded and "peened" (bent inward) the metal around the opening to make it touch the scab plate. The idea was to make this plate slightly recessed, if not flush, with the original contour of the pillar. This is because this pillar is covered with upholstery when the car is done and with some careful padding behind the material, this mount could be pretty well hidden. Note that the upper tab slices are rewelded also. 
The idea again is not to rely on the welding for the strength of the mount, but rather a heavy plate behind a panel, bolted via a small hole. The reality is that if this mount was stressed very hard, it would probably make a mess of the B-pillar, but it would hold. My theory is though that if I stress it that hard, I probably will have bigger problems with the car than a bunged up B-pillar. 
This is the left side, upper B-pillar mount after welding, grinding and cleaning up.
Here is the scab plate that was used for the lower B-pillar mounts. It has two holes because of how I will be mounting the belts at these points. Remember that the lower B-pillar mount secures two things; in a retractable belt setup, it holds the retracting mechanism and it secures the lap belt end on its outer side. In this '57 body, the lower section of the B-pillar mount was not nearly as wide as it is in the later model cars that are set up for retractable belts. You can't really see it in these pictures, but there just wasn't much room at all to insert and secure a scab plate into the lower B-pillar. My friend Bill was looking at it with me and said "Why don't you weld the plates back here and them make up a bracket that brings a mount forward?". It was an excellent idea.

This is the right side, the little bracket you can see is supports the rail that holds the forward bottom edge of the rear seat. To the left of that, outside of this picture, is the base of the B-pillar and then the door opening. I will make up a heavy bracket that bolts into the scab plate with 2 bolts, goes forward under the seat rail, and provides a mounting point for the seat belt mechanism right next to the B-pillar bottom. This area where the scab plate is welded is then under seat and cannot be seen. 
This is how the scab plate was secured for welding. With a little maneuvering and grasping, I was actually able to slip it down behind the panel via the interior panel area opening just above it and bolt it in place. The real reason why the smaller "plug" holes are where they are is that the heater channel ducting just inside of this area kept me from getting a good straight line access with the drill. This is the left side.
This is the left side, after welding. No, I didn't weld that myself, I let Tom do it for me. I wish I could weld that nicely. The welds will be ground down a bit, but not much as I don't want to weaken them. A washer or two will be used between the bracket and the panel to leave space for the weld beads. 
The following pictures show the implementation of the tunnel mounts. On the left, you can see both plates that were prepared (one is shown frontside, one backside) and the tunnel as it was drilled and ground. The references I had called for the mount to be higher up on the tunnel than I actually placed it (you can see a small hole above where I started to drill), but for some reason, I thought that it would be better more toward the vertical center of the tunnel. The smaller holes in the plates are to allow a couple extra welds for strength.

The hole in the tunnel was made with a 1 1/8" (28.5mm) hole saw. The three welds that hold the nuts to the back of the plates had to be ground just a bit to insure a flush fit in the hole. And you can't really see it, but the plates were placed in a vice and "bowed" just slightly to match the curvature of the tunnel side. The tunnel is ground to shiny metal where the plates will be welded. "Tar" from the tarboards that were removed made grinding a bit difficult, some lacquer thinner on a rag was used after grinding to make the metal clean.

On the right is the plate welded in, ground down and cleaned up with a wire brush (yes I did that weld). The new tarboards will be cut and fitted around the plate and will be about the same thickness as the plate. Thus, the mounts will not produce a noticeable protrusion under the tunnel mat.
As I was drilling the hole for the left side, I had this ominous feeling that there might be something on the other side of the tunnel wall. I vaguely remembered the fuel line being attached to the left side. As you can see in the picture on the left below, I was right. There was no fuel in the line and I was real careful not to drill beyond the tunnel wall metal.

I decided that if I could find the spot weld that held the fuel line bracket to the wall, that I could drill it out from the outside, move the line down a bit and re-tack it. I cleaned the surface with lacquer thinner and looked closely (grinding or even wire brushing will virtually erase any sign of spotwelds). The faint red arrow in the picture on the left shows what I guessed was the spot weld (I could feel the bracket with a finger in the hole and got a good idea how big it was). I drilled it with a 1/4" (6mm) drill bit and found that my guess was right, the bracket popped loose easily.

The line was easily pushed down about 3/8" and through the same 1/4" hole, I re-welded the bracket using a pair of long nosed vice grips to hold it in place. I guess now I know why VW placed the mounts higher.