Dave,
My understanding in NSW is:
a) if you are undertaking modifications that require an engineers certificate, then seat belts must be installed for
all seating positions. Lap/sash seat belts are required for all front and rear outboard seating positions. Lap/sash or lap belts shall be fitted to inboard seating positions. The level of safety provided by seat belts must not be reduced. Seat belts must not be replaced by belts of a lesser standard or with second-hand belts. For example, lap only belts must not be used in place of retracting lap/sash seat belts. The use of a retractable seat belt disabling device is not acceptable.This is based on the NSW RTA Vehicle Standards Information Sheets No 6. for light vehicle modifications.
b) if you do not require an engineers certificate, then you do not need to fit seatbelts. However, if you are carrying kiddies, the following apply:
Children younger than six months must be secured in a rearward facing restraint.
Children aged six months to under four years must be secured in either a rear or forward facing restraint.
Children aged four years to under seven years must be secured in forward facing child restraint or booster seat.
Children younger than four years cannot travel in the front seat of a vehicle with two or more rows.
Children aged four years to under seven years cannot travel in the front seat of a vehicle with two or more rows, unless all other back seats are occupied by children younger than seven years in a child restraint or booster seat.
I understand that the above child restraint laws are retrospective (i.e. that they are not "grandfathered" just because the FB/EK came out with no belts orginally). You would need to fit belts to meet the above.
d) if you are installing belts not for engineering certificates or for child restraint (but more for peace of mind) then you can choose which positions get belts and which don't.
c) Any installed seatbelts (even the peace of mind ones) must be approved by an RTA Authorised Restraint Fitting Station (
http://www.rta.nsw.gov.au/cgi-bin/index ... tting.form). This is not an engineers certificate, just an inspection and basic form to sign off and fairly cheap (>$100). Most fitting Stations will not let you do the work yourself (to a decent standard) and then inspect and certify it - most will only certify if they do the work themselves (in the end it's their signature on the line). It pays to check with the one you have in mind before you fire up the drill and spanners to DIY.
d) Some Fitting Stations require full compliance to ADR5 (
http://www.comlaw.gov.au/Details/F2009C ... 5628295870) when you install - there are some tricky bits in ADR/5 about how far apart the belts can be. Again, check with the Fitting Station you have in mind before flashing up the tools.
e) Most seatbelt installers require a minimum size of reinforcing plate to be used where you are bolting through a body structure. I can't remember where the legislation is for the minimum size for light vehicles, but seem to remember it is a mm2 requirement, not a "Xmm x Ymm" requirement. The bus/coach retrofit guidance (
http://www.rta.nsw.gov.au/registration/ ... /vib49.pdf) indicates 3750mm2 (75mm x50mm).
I could be wrong with the above understanding of NSW legislation - happy to hear alternative views.
You have a number of options to fit the belts:
a) Frankenstein the bolts through the B-pillar. This can be ugly (bolt heads on the outside), though is common. If you are going to do this, take a look at the UNF bolt head, and imagine just how much surface area under that bolt head actually holds the load in place during an acident... it's bugger all, which is how one seatbelt installer convinced me it's not too great an idea. When you fit the bolts, you must either fir anti-crush tubes or used bolts that prevent crush of the pillar by design.
b) You can cut a slot in the inner B-pillar skin and lower the flat plates down. The slot is normally welded back up.
c) The method I used was a little different. I ended up using a hole saw to cut a hole (26mm from memory) into the B-pillar (inside the car) at about shoulder height. I used a reinforcing plate of around 6"x1" (correct mm2 size) with a captive nut welded on the back. The plate was a cad-plated off-the-shelf job from the Inspection Station. I drilled two 1/8" holes in the reinforcing plate, one at either end, and made similar holes in the B-pillar (one above the 23mm hole, one below). I put a piece of fishing line on the plate and dropped it into the hole (catch it with the fishing line). Use the fishing line to pull it up, then put the seatbelt bolt into the plate (can't fall down now). Hold it in place with the bolt, and put a pop-rivet through the B-pillar hole into the plate. Repeat the pop-rivet for the other hole. You end up with a hole in the pillar with the plate behind it - can cover the hole with a plastic cap, though the seatbelt top "pulley" bit covers most of the hole once it is bolted in place. Seems a bit funny leaving a hole there, but the surface area of the plate is a shitload bigger than the surface area of the bolt-head used in "Frankenstein" set-ups (much less likely to pull through in an impact). This is the same process reccomended by one US seatbelt manufacturer to refit old cars.
Most signatories will not accept 2nd hand belts from the wreckers. I'd reccomend HEMCO (
http://hemco.com.au/seatbelts.html) - call them with the vehicle type, where you want the belts, what type and what colour and they will mail the right ones to you (at least they did for me with non-retractables into an FB - didn't try them out to see if they knew how to fit rolly belts).
Sorry for the epic novel above - took me a lot of fact-finding before I put belts into mine.
Cheers,
Harv.
327 Chev EK wagon, original EK ute for Number 1 Daughter, an FB sedan meth monster project and a BB/MD grey motored FED.