I have a Toyota Solara convertible (Photo from Toyota, not me, not my car, but it shows the floor plan well). It came with two seatbelts in the back seat, even though you could seat three people back there, albeit tightly. I assume they must have some kind of standard for how much space they want to allow per passenger and decided not to put a third seat belt because some of the width is taken up by the convertible mechanism.
I have a family of 4 and that means that I can’t drive it if one my kids wants to bring a friend, or if we tote MIL along.
Would it be safe to have a center seat belt installed? Is that something I could do safely myself?
Well I think installing it would work…but insuring it after you install it would be a different matter.
Insurance Agent: Ok Sir, your mother-in-law was riding in the middle between your son and your daughter…she had her seatbelt on. I don’t see that model Solara with a midseat seatbelt. Did you have a Seat Belt installed?
Mr. Gas: Uhhm - I bought a kit through hemmings that said it would fit…
Insurance Agent: When your MIL get’s out of ICU I will need to talk to her as well…
Make sure the factory approves any additions…and your insurance company
I doubt anybody would recommend this project, certainly not a dealer or responsible mechanic. The liability risk is just too great. (Shoot, a Toyota dealer wouldn’t sell me a seatbelt extender until they measured me in the seat and, apparently, got an engineer to sign off on the deal.)
So, with the understanding that I am not a responsible mechanic, and even I told you not to do this thing…
Look at how the existing seatbelts are mounted. If they’re bolted to the subframe under the seat, you might be able to mount a center seatbelt by doubling-up on the bolts that secure the inside ends of the existing belts.
There are, of course, a number of reasons not to do this. I’ll let you decide how important these reasons are:
The bolts might not be long enough to accommodate the extra thickness of the added brackets, and still engage enough threads to hold securely. Hence, the bolts might strip or break out in an accident, jeopardizing all three rear-seat passengers (and any other passengers they might hit in the accident.)
You might or might not know how, or be able to, remove the bolts without damage, reinstall the bolts and apply the required torque to the bolts, or use the necessary thread compound, if any. So the bolts might strip (if over-torqued), or back out (if under-torqued or improperly treated). You might be able to get the torque and thread compound recommendation from the manufacturer or a service manual.
The subframe hard points where the existing belts mount might not be strong enough to hold three passengers securely in an accident. However strong they might be, they will fail sooner with three passengers than they would with only two.
There’s no telling what you might get when you go hunting for seat belt parts. Will they be strong enough? Will their mounting plates interfere with the existing belts? Will they latch and unlatch reliably?
Your car’s roll-over protection (whatever form it might take), may not operate properly with a third person in the back seat.
There may be other, even more dreadful objections that I haven’t thought of.
[On edit: I hit submit accidentaly. Just be really careful, OK? I’m only an average-intelligence tinkerer, not a certified anything. ]
Shops that prepare racing cars also install seat belts. You could ask them whether it is possible to do on your car and they will probably know about any legal issues.
Oh, the old MIL problem. If you watch old cartoons, you can easily see that the main issue is that she doesn’t hit anyone else on her way through the windshield. Cue humorous melody.
I once broadsided a Toyota Solara at about 40 MPH. The 3 teenage girls in the car were totally uninjured, but if there had been 3 people in the back seat, someone would definitely been crushed.
The back seat of the Toyota was a good 12-18 inches narrower after the accident.
I’m still not sure how the driver wasn’t hurt because back end of the door was pushed halfway into where the driver’s seat had been.
I guess the car is built for everything to move over rather than just crush whoever is sitting on the other side of the metal.
If the car doesn’t have the middle seatbelt, it’s for a good reason.
