I used 7/16 fine thread grade 8 bolts with a seatbelt but on the back side with a few washers on both sides. Using a spacer through the hole would be a recommendation so you don't compromise the strength of the rollbar anymore than necessary...used the existing lap belt mounts for the other 2 points.
Does your roll bar have the boss in the tube just above your left shoulder? If not, pick up a 1/2" pipe close nipple about 6" long at the hardware store. Drill a hole though the roll bar just big enough to get the pipe though. Once its in, weld it on both sides, then cut it off and grind it down to just above the welds. Chase it with a 1/2" drill bit to clean it out. Prime, paint, install belts.
Rock of the Marne!
You can see the stock mounting hole in mine (before I did my cage work) right below where the rear angle bar comes into the main hoop.
Im using 4pt belts in mine. I added a bar behind the front seats to properly mount the belts to. I used the pipe nipple as an anti crush sleeve.
Beat it to fit, paint it to match!
I understand the need for these but remember the bar is not (or usually not) hooked to the seat, so a compression situation could exist in a roll over where the bar seperates from the tub. Another reason to tie to the frame.
You can see one welded in were the padding is cut away.
Thank you for the response guys... exactly information I need.
82JeepCJ7, that is exactly the pic I needed to see location of original mount in 1982 roll cage (same cage as mine, blots to floor plates behind seats). Rock of the Marne! 3/7 Infantry.
The Jeep originally arrived with a set of really nice Corbeau Baja SS seats, with 4 point harnesses. The driver's seat even has the heater in it (not connected), and passenger side with slider. At 6'4", the thick SS seats were touch to deal with. Also, the original driver's seat mount was cut up and modified with angle iron, to put the seats uncomfortably close to the steering wheel (original owner must have REALLY short).
The Jeep will mostly see time on the road in nice weather, and mild off-road. I am installing a set of generic Rugged Ridge reclining seats (they look decent, tolerable, and are narrow enough to clear roll cage). The 3 point seat belts will be easier to deal with, and appreciated by my wife. I have preinstalled the seats with '87 Wrangler risers, and post '92 sliders for lowest seat height... works great! I have to weld/modify the risers, as the Z bar attached to the flip lever, as it hits floorboard step behind the seats (not a big deal). While at it, based upon images found on this sight, I am cutting the wheelwell back a couple inches to allow a little more leg room (2.5" spring lift, 32" tires, plenty or room). Thankfully, as the Jeep came from the SW desert, all the threads in the floorpans clean and serviceable, with no hidden body rot to contend with.
I will post pix in July, as I leave for five weeks of military training tomorrow.