I'm one of the weld in advocates. I mounted the second mounting on the driver's side of my 1970 MGB a couple of months ago, so now have some road time to make comments about. I'd also like to go on record as being one of the movers and shakers of getting seat belts into the catalogs as I'm an advocate of retractable belts.
I'll do a photo shoot when I weld in the passenger side boss and see about getting it up on the website or in British Motoring. It was late at night when I did the driver's side, so the images might have come out a bit lurid.
1. In 1973 the trans tunnel belt mounting points were moved forward by about 4 inches. This allowed the use of the shorter steel cable receiver assembly. In earlier cars, if you normally have your seat all the way back, you can still mount the 222-025 stalk mounted receiver belts, but if you have shorter legs you may either need to add a strap to extend the stalk or use the 222-030 belt set which has traditional, non stalk mounted latches. I'm 5' 9", weigh 185 lbs and really like the stalk mounted receiver in my 1970 MGB. No fumbling for belt ends.
2. The weld in captive nut mount that was fitted to the 1973 onward MGBs is really the way to go if you want a shoulder harness. It really isn't a big deal to install.
a. Jack up the car and remove the rear wheel
b. Lift up the carpet over the wheel arch. Do this carefully as the carpet tufts can pull out. Fold the carpet as far back as possible so that it will not be damaged by the heat of welding.
c. Use a hole saw to cut a hole through the inner fender about 1" up from the battery cover ledge and as far back as you can without cutting through the double layer flange.
d. Offer up the mount assembly from the outside. Make sure that it will sit flush against the wheel arch. Drill or stamp four holes in the outer mounting flange, then grind off the paint on the inner arch where it mounts.
e. Plug weld the four holes, giving time between each weld for the metal to cool off and ensure that the interior trim is out of the way of the welded area. You are welding on the outside of the inner fender, so there is not much chance of any welding sparks hitting the interior of the car but take all rational precautions.
f. Once the welds have cooled, clean the areas with a wire brush then prime, paint and undercoat as you wish.
g. Fold the carpet back over the wheel arches, install the belts and away you go.
Alternatively the mounting plates could be installed using modern auto body adhesives. The boss flange is on the outside of the sheet metal, so it would take an incredible force to pull it through. Modern adhesives are more than strong enough for this application as long as the mounting surfaces were correctly cleaned. This would require no welding and would be as strong, if not stronger.
Drop me a line if you have any questions, I'd be happy to go over the work I did
Global Sourcing Engineer
Moss Motors, Ltd.
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