Need Help: Rear Shoulder Seat Belt Conversion

[wsutard]

Can anyone help guide me on how to put rear shoulder seat belts in my 69 Coronet? Currently it has lap belts only and that isn't very safe for my kids.

I have done searches and haven't come up with any ready made kits.

 

[mmissile]

We just bounced off the front seat, back in the day. Ya get used to it.

 

[Mike67]

Ive been contemplating installing 4 pt harnesses for the very same reason ( I think 3 pt are dangerous for kids)....plus I have a shoulder bar that would be catastrophic if some one were to hit it.
Ive looked at welding in reinforcing plates in the tray or welding a cross bar on the 2 down tubes for mounting points in the trunk.

 

[Billccm]

Disclaimer: I am not an auto safety expert. I did work in the high speed camera industry and our biggest customer was the auto companies to recorded high speed digital crash videos. I did get to witness a new SUV going through crash tests in Michigan 15 years ago.

You may be doing more harm than good unless you anchor high above the rear seat backs. You can't really anchor to the pillars unless you drilled holes and showed external bolt heads, and I'm not sure how stout the pillar really is in a crash. Thinking out loud you would have to take a block of metal and mount on the package tray for the shoulder anchor, then reinforce under the package tray. Even then, I'm not sure you have made a safety improvement.

The rear seat back is fairly high in these B Body cars (whiplash is reduced somewhat), and in the back seat the lap belt does provide safety in that it keeps you seated. Lap belts are very good; the airline industry has everyone in a lap belt except the pilots.

 

[HT413]

Anything you do will be 'custom' and if a kid gets hurt you'll kick yourself for the rest of your life.

What I did is install something like this - a 5 point booster seat that can handle up to 120 lbs. It effectively turns your lap belt into an approved 5 pt restraint. This one happens to be really expensive but there are ones that are far more reasonable. Like mentioned, just make sure the one you get allows the shoulder straps to be mounted at or above your kids' shoulders.

https://m.toysrus.com/product/index...plab_19773094&eESource=CAPLA_DF:50111766:TRUS

 

[oldbee]

I haveto go with billccm, unless you go with a pair of eyebolts with a length of 1/2" rope side-to-side under their armpits; just kidding. Those attachment points are pretty beefed up for upper part of belt.

 

[wsutard]

Anything you do will be 'custom' and if a kid gets hurt you'll kick yourself for the rest of your life.

What I did is install something like this - a 5 point booster seat that can handle up to 120 lbs. It effectively turns your lap belt into an approved 5 pt restraint. This one happens to be really expensive but there are ones that are far more reasonable. Like mentioned, just make sure the one you get allows the shoulder straps to be mounted at or above your kids' shoulders.

https://m.toysrus.com/product/index...plab_19773094&eESource=CAPLA_DF:50111766:TRUS

Funny enough, I have two of those exact seats. One of my kids is too big for that anymore.

I'm just going to say that I am not in the "lap belts are as safe as shoulder belts" camp. Airplanes and cars are not the same thing. Cars have sudden horizontal impacts, planes have sudden vertical movement. There is a reason all cars have shoulder belts now, they are safer.

What I don't understand, but want to, is the comments about the shoulder mounted above the shoulders. Why is this a necessity?

 

[Billccm]

I believe (read my disclaimer again) that is has more to do with the angle of the belt facing downward from the occupants head. I got this out of my my old Takata safety booklet (BTW, those 'safe' airbags from Takata have killed 15 people to date):

"When mounting shoulder belts to a harness bar, the optimal angle of the shoulder belt (from the horizontal plane) is between 0° and 20° downwards from the top of the occupants’ shoulders or seat back opening."

 

[Mike67]

Funny enough, I have two of those exact seats. One of my kids is too big for that anymore.

I'm just going to say that I am not in the "lap belts are as safe as shoulder belts" camp. Airplanes and cars are not the same thing. Cars have sudden horizontal impacts, planes have sudden vertical movement. There is a reason all cars have shoulder belts now, they are safer.

What I don't understand, but want to, is the comments about the shoulder mounted above the shoulders. Why is this a necessity?

From the reasearch I did on mounting points of harnesses was the possiblity of crushing the spine.... Im guessing the same could be said for 3 pt....only guessing though....

 

[HT413]

I read somewhere that if the shoulder straps mount too far below the shoulder, it can cause a downward compression force upon impact, which can hurt their spine and shoulders.

 

[HT413]

I believe (read my disclaimer again) that is has more to do with the angle of the belt facing downward from the occupants head. I got this out of my my old Takata safety booklet (BTW, those 'safe' airbags from Takata have killed 15 people to date):

"When mounting shoulder belts to a harness bar, the optimal angle of the shoulder belt (from the horizontal plane) is between 0° and 20° downwards from the top of the occupants’ shoulders or seat back opening."

And there ya go, I read the opposite: 0* to slightly positive angle. Lol

 

[wsutard]

Makes sense with a low mounting position possibly causing spinal compression/injury.

I guess if I want to move forward with this I will need to fab something up myself since it doesn't seem like there are kits for this. For some reason I thought shoulder belts were an option on B Bodies.

 

[Billccm]

I guess if I want to move forward with this I will need to fab something up myself since it doesn't seem like there are kits for this. For some reason I thought shoulder belts were an option on B Bodies.

As safety conscious as people are nowadays, you could probably make money on selling kits. Having said that, you would have to create a LLC with a 10 million dollar bond to protect yourself against litigation.

 

[440+6]

Rear shoulder belts where an option in these cars, the package tray has the slots for them.
If you look in the codes you will find them, I have never seen them in a car but would like to add them to my car too.

 

[HT413]

Interesting, I never knew the cars had that option. I found this thread on moparts with some interesting pictures...

http://board.moparts.org/ubbthreads...4/c14-rear-shoulder-belt-option-69-dodge.html

 

[HT413]

 

[6290988]

C13 69-70 Front Shoulder Belts
C14 69-71 Rear Shoulder Belts


Does anyone reproduce the parts needed to convert the rear and front? That is the first thing I'd do to my 69 Satellite when I get it next week.

 

[HT413]

Most places sell the front shoulder straps, including Year One, etc. The mounting points are, I believe, in all cars and consist of a flat, rectangular nut that is welded in place. It's concealed by the head liner near the B pillar if I recall. Rear shoulder belts? Never noticed them for sale myself.

 

[Mike67]

Would be interesting to seer if someone can come up with the reinforcing plate for the shelf...
Thanks HT!

 

[6290988]

Does anyone have a real picture of the reinforcement plate? I'm sure if I had a picture I could make that.