3 point seat belts

[Brian Kulis]

I would really like to convert 4 of my belts to 3 point seat belts. Please give me any advice on where to purchase the belts and how to install them.

 

[Stanglover]

Seatbelt Panet I think is the better company. I bought mine from a supplier for Seat Belt Solutions. There was been a lot posted before on this subject. Being as you have a vert, you'll need to do some homework I think. Do a Google search as well. This post may help, it's one of my old ones.
https://7173mustangs.com/threads/re-visiting-3-point-seat-belt-conversions.36970/

 

[boxgranch]

There are problems with putting shoulder belts into a convertible. The shoulder belt needs to be mounted so it does not compress your spine. I forget the details, but you definitely have to mount them someplace around shoulder height. I can't find it now, but a fellow someplace had a bar made that ran behind the seats to do this. Others put in a roll bar and add a second level to attach the belt. If I can ever find the link, I will post is.

 

[giantpune]

There are problems with putting shoulder belts into a convertible. The shoulder belt needs to be mounted so it does not compress your spine. I forget the details, but you definitely have to mount them someplace around shoulder height. I can't find it now, but a fellow someplace had a bar made that ran behind the seats to do this. Others put in a roll bar and add a second level to attach the belt. If I can ever find the link, I will post is.

I've wrecked a '72 car doing 35MPH, uphill. The impact was enough for my face to hit the steering wheel pretty hard.
I wonder what the trade off is between a 2pt seatbelt letting your face hit the steering wheel vs a low mounted 3pt compressing your spine.

 

[tony-muscle]

According to the standards you should be fine as long as the angle of the seat belt is no more than 40 degrees from a horizontal line that crosses your shoulder, see picture below.
Section 571.210 of the Federal Motor Vehicle Safety Standard: https://www.law.cornell.edu/cfr/text/49/571.210

 

[mrgmhale]

When we got our 73 Mach 1 it only had lap belts or the front and rear seats. I am certain it was supposed to have shoulder belts also, as even our 1969 Shelby GT500, and 1969 Mustangs (in high school and early college, 70s), were built with shoulder belts. The 1969 Shelby design is far different then the 1969 Mustang design, as the upper ends of the shoulder belts are attached to the top of the roll bar, behind the front seats.

I do not see any holes in the roof lining fabric where anchors for the 1973 Mach 1 shoulder belts would have been bolted to. I bet the anchors exist, but until reading this thread I have been trying to just ignore the missing belts (what could possibly go wrong?!?). But, now I am getting all fired up again on the subject.

We also have a 1973 Mustang Convertible. I see nowhere in its original roof's metal framework to bolt a shoulder belt's upper anchor to either. I really do not want to install a roll bar, like we have in our 69 Shelby, to mount an upper shoulder belt to. The vert is really quite unmolested as it was barn stored for over 40 years, has just a little over 20,000 original miles on it, and I do not see where anybody has done any kind of "custom work" (or hacking) on the convertible top/s metal lattice framing. Time for me to do some more research I think. Funny thing, I was just beginning to think of how few projects I had on hand for this now opening Car Season. Well, I guess that is "fixed" now...

 

[boxgranch]

According to the standards you should be fine as long as the angle of the seat belt is no more than 40 degrees from a horizontal line that crosses your shoulder, see picture below.
Section 571.210 of the Federal Motor Vehicle Safety Standard: https://www.law.cornell.edu/cfr/text/49/571.210

Tony, thanks so much for posting all of that. It will go into my archive for when we can have something made. I wish Ford would have done what British Leyland did on my 69 MGB and routed the shoulder belt to the rear deck, but that would have compromised the back seats in the Mustang a bit. On the MG, you could unsnap the shoulder belt to get the top up and down which really was pretty easy.

 

[Stanglover]

When we got our 73 Mach 1 it only had lap belts or the front and rear seats. I am certain it was supposed to have shoulder belts also, as even our 1969 Shelby GT500, and 1969 Mustangs (in high school and early college, 70s), were built with shoulder belts. The 1969 Shelby design is far different then the 1969 Mustang design, as the upper ends of the shoulder belts are attached to the top of the roll bar, behind the front seats.

I do not see any holes in the roof lining fabric where anchors for the 1973 Mach 1 shoulder belts would have been bolted to. I bet the anchors exist, but until reading this thread I have been trying to just ignore the missing belts (what could possibly go wrong?!?). But, now I am getting all fired up again on the subject.

I'm guessing that maybe the head liner has been changed which covered the anchor point in the roof on your 73 Mach 1. It was law by then to have at least a detachable shoulder belt. I don't have direct knowledge of the 73's belts, but on my 71, the shoulder belt and the lap belt are separate, clipping together at the buckle when needed. Dumb idea!!!
If you feel around where the roof mount point ought to be, I'm sure you'll feel it, so just pierce a small hole for the through bolt.
If you buy new 3 point belts, make sure the lap section has the long "C" bracket that mounts behind the retractor with the same bolt. The install should be very easy. One more thing, on the tunnel belt part with the buckle, do not get the sleeve or at least make sure it is the correct length. On the set I got, this was totally incorrect and I ended up modifying the cover. I think my link shows those pictures, if not I can repost them.

 

[rcadd1ct]

The third belt mount on my 72 fb is being used when I put in retro belts 3 point conversion. Please be aware that the lap belts have larger diameter bolts than the shoulder belt. This was fine when it was added to the existing lap belt, but not ok when you redo the design to a modern style seatbelt. All three mount points now take even load. I drilled and tapped the top mount to accept the same hardware as the lap belt.

to get the shoulder belt angle better I am looking for a soft mount extension to drop the top mount pivot point lower to help with spine compression.

 

[jdomke1]

I can’t figure how to get the stupid belts to hang above the door. Mines a std Mach 1. I’m thinking of just saying no. Put in seats with 3 or 5 point harnessed.

 

[Stanglover]

I can’t figure how to get the stupid belts to hang above the door. Mines a std Mach 1. I’m thinking of just saying no. Put in seats with 3 or 5 point harnessed.

There ought to be a "coat hanger" looking piece near the front A pillar where the loop on the original shoulder belt hangs. There is also a spring like piece the fits between the head liner and the top door trim about midway to slide the belt behind.
I think this was also covered in my lengthy post linked in post #2 here. Check it out.

 

[Stanglover]

The third belt mount on my 72 fb is being used when I put in retro belts 3 point conversion. Please be aware that the lap belts have larger diameter bolts than the shoulder belt. This was fine when it was added to the existing lap belt, but not ok when you redo the design to a modern style seatbelt. All three mount points now take even load. I drilled and tapped the top mount to accept the same hardware as the lap belt.

to get the shoulder belt angle better I am looking for a soft mount extension to drop the top mount pivot point lower to help with spine compression.

Call me stupid, but I have no idea what you're talking about. When I did my conversion, it used all the original hardware. I did not have to drill and tap anything or use different size bolts. It took me all of 1/2 hour to do both sides. However, I did need to rethink the tunnel belt cover pieces as the sleeves supplied were nowhere near being correct for my seat position.
You can order belts with a drop sash. Mine, from Wesco/Seatbelt Solutions has an 8" drop. Other brands may have better sashes. I think Seatbelt Planet has a better design. Also as mentioned, you also need to order with a long "C" bracket that connects the lap portion to the back of the retractor using the same bolt..

 

[rcadd1ct]

Call me stupid, but I have no idea what you're talking about. When I did my conversion, it used all the original hardware. I did not have to drill and tap anything or use different size bolts. It took me all of 1/2 hour to do both sides. However, I did need to rethink the tunnel belt cover pieces as the sleeves supplied were nowhere near being correct for my seat position.
You can order belts with a drop sash. Mine, from Wesco/Seatbelt Solutions has an 8" drop. Other brands may have better sashes. I think Seatbelt Planet has a better design. Also as mentioned, you also need to order with a long "C" bracket that connects the lap portion to the back of the retractor using the same bolt..

The top bolt is a smaller diameter. This was fine as it only needed to hold the torso while the lap belt did most of the work.

then you add:

https://www.summitracing.com/parts/rt-6573mstblk/make/ford/model/mustang/year/1972
now the whole body weight goes up to the smaller top bolt. This is the weak spot and will bull out easier than the larger lap belt mounts.

 

[Mister 4x4]

I'm with Geoff - I picked up a 3-point kit from CJ Pony Parts for my Mach 1 and literally bolted everything in at the factory anchor points. They were in and working properly in about a half hour.

Unfortunately, bkulis (the original poster) has a 'vert. I know someone's done this before - hopefully, they'll chime in to help. (The paint came out awesome BTW, BK - that's turning out to be a gorgeous car)

 

[giantpune]

When we got our 73 Mach 1 it only had lap belts or the front and rear seats. I am certain it was supposed to have shoulder belts also, as even our 1969 Shelby GT500, and 1969 Mustangs (in high school and early college, 70s), were built with shoulder belts. The 1969 Shelby design is far different then the 1969 Mustang design, as the upper ends of the shoulder belts are attached to the top of the roll bar, behind the front seats.

I do not see any holes in the roof lining fabric where anchors for the 1973 Mach 1 shoulder belts would have been bolted to. I bet the anchors exist, but until reading this thread I have been trying to just ignore the missing belts (what could possibly go wrong?!?). But, now I am getting all fired up again on the subject.

My car was the same way. 1973 mach1, lap belts and no shoulder belts. Turns out, the things I thought were luggage tie downs in the trunk for 20 years were actually the shoulder belts. And I think somebody had replaced the headliner and never bothered to cut the holes for the shoulder belts. Looking at some photos from on here, I got an idea where to feel around, and sure enough, if I press on my headliner in the right spot, I can feel the holes where my shoulder belts would mount.

I have enough experience with other cars from this era that I know I don't like this stile of seat belts where the shoulder belt is not retracted on its own. I would like to replace what I have with something that behaves the way seatbelts have acted since around the mid 80s.

I'm with Geoff - I picked up a 3-point kit from CJ Pony Parts for my Mach 1 and literally bolted everything in at the factory anchor points. They were in and working properly in about a half hour.

Do you have a link or a part number?

 

[jdomke1]

There ought to be a "coat hanger" looking piece near the front A pillar where the loop on the original shoulder belt hangs. There is also a spring like piece the fits between the head liner and the top door trim about midway to slide the belt behind.
I think this was also covered in my lengthy post linked in post #2 here. Check it out.

I guess I’m just missing the spring part. The loop is very stretched out so I’m just letting them hang. Thank you.

 

[Stanglover]

I guess I’m just missing the spring part. The loop is very stretched out so I’m just letting them hang. Thank you.

I think the springy thingy is available. NPD list it, part #61280-4A. That is in an old catalog though.
As for the original belts, I think someone mentioned that they can be re-webbed. It could be Seatbelt Planet that will do them. Don't quote me though.

 

[Stanglover]

My car was the same way. 1973 mach1, lap belts and no shoulder belts. Turns out, the things I thought were luggage tie downs in the trunk for 20 years were actually the shoulder belts. And I think somebody had replaced the headliner and never bothered to cut the holes for the shoulder belts. Looking at some photos from on here, I got an idea where to feel around, and sure enough, if I press on my headliner in the right spot, I can feel the holes where my shoulder belts would mount.

I have enough experience with other cars from this era that I know I don't like this stile of seat belts where the shoulder belt is not retracted on its own. I would like to replace what I have with something that behaves the way seatbelts have acted since around the mid 80s.


Do you have a link or a part number?

There were no shoulder belts for the back seat. Is that what you're referring to?
There would have been separate shoulder belts for the front seats I'm sure. It is odd that two of you had a 73 without front shoulder belts. Again, I assume everybody is talking about the front seat belts in this thread.
As for belts from NPD or CJ Pony etc. they're probably made by the same companies mentioned, but I had a problem with a set I bought from NPD. a) they had the wrong buckles, b) they had a nasty twist in them I didn't like, so I sent them back. One thing I will add about ALL of the aftermarket belts I've seen, is that the buckle tongue is NOT free sliding as our modern belts are. It means that the shoulder belt won't retract all the way because the buckle tongue, once adjusted to your seat position, is fixed. I hope that make sense.
We are waaaay off track now with the original request about seat belts for a Convertible. Back to the program!!

 

[tony-muscle]

Not a convertible, but here was my workaround to add a 3-point seatbelt to my Mach 1 with fold down seats. It would be more straight forward without fold down seats.
https://7173mustangs.com/threads/added-a-3-point-seat-belt-to-my-fold-down-rear-seats.35703/

 

[Mister 4x4]

Do you have a link or a part number?

Do ya one better, here's a link: https://www.cjponyparts.com/seat-be...-coupe-1968-1973-fastback-1965-1973/p/SBR7-V/

As well, here's a link to a kit that will fit the 'verts: https://www.cjponyparts.com/seat-be...upe-1965-1967-convertible-1965-1973/p/SBR6-V/

Hope this helps!