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Seat Belts


Jim Neville
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Hello all. My '50 Windsor Convertible is finally ready for some cruising. New wire harness, fuel pump, new Coker tires, fuel sending unit, new brakes, etc. I would like to put seat belts in it once the cold weather hits. Because it's a convertible, I can only put lap belts in. Has anyone put belts in a convertible? Not sure how to anchor them. Does anyone know of a seller in Canada that would sell these? Thanks.

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I have not put seatbelts in my Plymouth yet. Here is a video on it. My biggest concern would be the anchorage to the bottom of the car. Making sure it won't tear through the sheet metal should something happen.

 

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This is one of those areas where clear-eyed thought is useful. I installed only lap belts in the '48 P15 four-door sedan since I haven't figured out a way to install shoulder harnesses with the suicide rear doors. The belts are anchored to the floor with large diameter steel washers which should withstand a huge load, the belts (or my body) would probably fail before the anchors could rip free.

 

However...it is most likely a moot point. There is a rigidly mounted steel spear a few inches in front of my chest which will almost certainly perforate my body before the belts give way. Let's face it, these old cars cannot be brought up to anywhere near the safety margins of a modern vehicle. The lap belts give me a measure of comfort and will hopefully keep me in the car in case of an accident, but my best approach is the same as when I was riding motorcycles many years ago.....relentless defensive driving habits.

 

To your question, lap belts are available in the states from a variety of the usual vendors, I suspect the same is true in Canada.

 

seat-1.jpg.8d991d804b3f11f4b24e35d324eb8bf2.jpg

Edited by Sam Buchanan
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I put lap belts in my Dodge coupe years ago using belts from Julianos hot rod parts.  They sell a heavy duty anchor plate with rounded edges to go under the floor.  The rounded edges hopefully will keep the plates from cutting the sheet metal floor.  So far my seat belts have not been tested and like Sam says I am doing my best to ensure that they aren't.

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4 minutes ago, Jim Neville said:

Thank you for you reply. Yes I agree that defensive driving is the key to staying safe in these old beauties. Do you know the length of the belts that you put in your '48 P15?

 

Retro Belt, 75":

 

https://www.retrobelt.com/products/aviation-style-lap-belt?rq=yr_1948~mk_plymouth~md_special-deluxe

 

258-BLK-75_240x240.jpg

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I attached lap belts to the front seat frame after I reinforced the area a little so they move with the seat.  These cars will kill you in a wreck and seat belts are there just to keep you from flying out of the car.  Coming to terms with this one realizes lap belts are all that's needed and shoulder belts are a waste of time.  The car will still kill you but at least you're strapped in for the entire ride.

Edited by Adam H P15 D30
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34 minutes ago, Adam H P15 D30 said:

I attached lap belts to the front seat frame after I reinforced the area a little so they move with the seat.  These cars will kill you in a wreck and seat belts are there just to keep you from flying out of the car.  Coming to terms with this one realizes lap belts are all that's needed and shoulder belts are a waste of time.  The car will still kill you but at least you're strapped in for the entire ride.

 

Wow......getting slammed into the steering column (or dash for the passenger) by the weight of the seats.........no thanks.  😨

 

Every safety harness installation document I've seen says you always...always, anchor to body super structure (floor, body, roll cage, fuselage, etc). It is assumed that seat anchors will fail under high-G loads of the occupant's weight.

 

Just snapped this photo since I have the front interior out for a clutch job. The lap belts are anchored to the floor and come up between the bottom and back seat cushions. Please excuse the untidiness, it'll get cleaned up after I'm finished crawling around in the car.

 

image.jpeg.19d9e2fda00ee52dbb979f2082ed65a7.jpeg

 

 

I still want shoulder belts, but may have to give up on retractable belts due to space restrictions in my car. 

 

 

seat-2.jpg.064193fbf5649cc31d917e0f7ad4e438.jpg

Edited by Sam Buchanan
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I plan to attach the lap belts to the seat frame, but will completely rebuild the lower structure of the seat frame.  My reasoning is that the seat frame, especially the sliding adjustment mechanism, was not designed to resist the weight of more than the seat itself.  So the occupant's weight will over-come the strength of the mechanism, and the seat will break free from the lower frame supports.  (I don't know, but maybe even the attachment to the floor is not sufficient, so I will change that part as well.)  

I don't want to just run the seat belts behind the seat cushion and then down to the floor, because the angle is too sharp, unless you cut holes in the footrest on the back of the front seat, and attach the seat belts back into the rear passenger floorboard area.  I know that some say they "never have rear seat passengers anyway", so it doesn't matter, but that's not my situation or expectation.

 

I do plan to put in shoulder belts, but I'm also concerned about whether the sheet metal in the B pillar is sufficient to resist just having a chunk of it ripped out and jerked past the occupant's neck. 

 

Then yes, there is that "spear" right in front of you.  But it seems to me that a shoulder belt would make a noticeable difference in how far the driver's upper body is thrown forward.  I have looked a bit at modifying the steering column, and I think that one of the challenges would be to incorporate a column support that does not use an attachment point on the underside of the dash.  It seems to me that it needs to support the column farther back.  Then there is the shifter rod, and I haven't examined that closely, but I think that it would be able to slide down farther into the engine compartment, although the linkage would probably prevent any appreciable movement there.  I think, however, that there is a tendency to think in terms of the crush zones of modern vehicles, and these vehicles are not going to compress in an impact the way modern vehicles do.  So there are at least two resulting dangers from that - 1) the full force of the impact is transferred to the occupants, and so the forward thrust of body weight is greater than in a modern vehicle, and 2) in a body on frame construction there is also the danger that the body will be torn loose from the frame, because the frame is stiff enough that it is not likely to absorb much of the impact, and if the frame to body attachment points are compromised from rust, then it's possible for it to break free.  So then you still end up with that spear right in front of you, no matter how well you are anchored to the seat, or to the body.  I actually think that in many old cars the second item here is the one that receives little to no attention (especially if it was not a body-off-frame restoration, which most are not, from what I can tell).

Edited by Eneto-55
spelling error
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24 minutes ago, Eneto-55 said:

I plan to attach the lap belts to the seat frame, but will completely rebuild the lower structure of the seat frame.  My reasoning is that the seat frame, especially the sliding adjustment mechanism, was not designed to resist the weight of more than the seat itself.  So the occupant's weight will over-come the strength of the mechanism, and the seat will break free from the lower frame supports.  (I don't know, but maybe even the attachment to the floor is not sufficient, so I will change that part as well.)  

I don't want to just run the seat belts behind the seat cushion and then down to the floor, because the angle is too sharp, unless you cut holes in the footrest on the back of the front seat, and attach the seat belts back into the rear passenger floorboard area.  I know that some say they "never have rear seat passengers anyway", so it doesn't matter, but that's not my situation or expectation.

 

Thank you for a thoughtful post!

 

I agree the way I have my belts attached to the floor doesn't offer the optimum angle. I looked at that for quite a while before deciding everything safety-related about the car was a huge compromise....then accepted the compromised attachment angle.

 

At least I now have disc brakes!  That makes me feel a little better....  😁

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The steering column "spear" should give us pause. 

I think I have ameliorated the problem in the process of adding power steering to my 47DeSoto. 

I cut the column jacket just below the shifting stuff, and secured the column and shaft with a bushing and a bracket bolted to the cowl. 

I added a spline to the cut end of the steering shaft itself, and I used the appropriate U-joints and D-shafts to connect the steering shaft to the new steering box. 

The shafts do not line up, so I hope that the shaft segments will fold upon themselves, if ever necessary to do so.  

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3 hours ago, Sam Buchanan said:

 

Wow......getting slammed into the steering column (or dash for the passenger) by the weight of the seats.........no thanks.  😨

 

Every safety harness installation document I've seen says you always...always, anchor to body super structure (floor, body, roll cage, fuselage, etc). It is assumed that seat anchors will fail under high-G loads of the occupant's weight.

 

Just snapped this photo since I have the front interior out for a clutch job. The lap belts are anchored to the floor and come up between the bottom and back seat cushions. Please excuse the untidiness, it'll get cleaned up after I'm finished crawling around in the car.

 

image.jpeg.19d9e2fda00ee52dbb979f2082ed65a7.jpeg

 

 

I still want shoulder belts, but may have to give up on retractable belts due to space restrictions in my car. 

 

 

seat-2.jpg.064193fbf5649cc31d917e0f7ad4e438.jpg

Almost every modern vehicle attaches part or all of the seat belt anchor points to the seats.  I don't think I would put then where you did though...

In order to make shoulder belts even marginally effective, you will have to seriously reinforce your B-pillar and roof area.  With the skinny B-pillar it may not even be doable.

I wouldn't worry about being slammed into the steering column, it will come to you and fast.  Modern vehicles use collapsible columns

Part of the "charm" around driving these old vehicles

Edited by Adam H P15 D30
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24 minutes ago, Adam H P15 D30 said:

Almost every modern vehicle attaches part or all of the seat belt anchor points to the seats.  I don't think I would put then where you did though...

In order to make shoulder belts even marginally effective, you will have to seriously reinforce your B-pillar and roof area.  With the skinny B-pillar it may not even be doable.

I wouldn't worry about being slammed into the steering column, it will come to you and fast.  Modern vehicles use collapsible columns

Part of the "charm" around driving these old vehicles

 

Yep, we are definitely chopping with a dull hoe when it comes to enhancing safety in the old cars. It's a matter of deciding how much risk we wish to manage.  🙂

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One of my ‘musts’ on my truck was/is a later steering column.  One that collapses on impact.   My choice is an 80 firebird from a floor shifted car.   No shift lever to delete. I elected to use a power steering gear but if I were not doing that the original shaft would have been cut and adapted to the column. 
 

belts are yet to come but will be mounted to the seat frame and door opening.  But my 56 seat frame is welded to the floor. 

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2 hours ago, Adam H P15 D30 said:

Almost every modern vehicle attaches part or all of the seat belt anchor points to the seats.  I don't think I would put then where you did though...

In order to make shoulder belts even marginally effective, you will have to seriously reinforce your B-pillar and roof area.  With the skinny B-pillar it may not even be doable.

I wouldn't worry about being slammed into the steering column, it will come to you and fast.  Modern vehicles use collapsible columns

Part of the "charm" around driving these old vehicles

I hadn't thought about whether the B pillar itself would not be strong enough - I was just thinking about the sheet metal that closes it in on the inside, and how (at least on my 46) the spot welds that hold it in place are fairly widely spaced.  (I described else where how I am thinking of reinforcing it, with screws or welds through the B pillar sides both front & back.)  I guess I would think that it would require a pretty hefty force to rip the top of the B pillar completely loose.  (I would think that by that time the belt itself would have done serious damage, if the pillar didn't give way.)

 

About the steering "spear".  The steering sector on our cars is around 8 or 9 inches behind the center line of the wheels, where as most modern cars have it well in front of the front wheel center line (S-10 PUs, for instance, a popular frame for frame swaps).  I only personally know of one person killed by the steering shaft.  Well, I didn't know him personally, I met the family after the widow had already been remarried for some years.  (I think their youngest child was from her second marriage, and he was around 12 years old then.)  But she was so "safety conscious" that she had insisted that shoulder belts be installed in the rear seat as well.   It was in 75 that I met her.  I don't remember what year or make their car was, but it was the first time I had ever seen a car with shoulder belts in the rear seat.  I don't think any cars of that era offered that, but I could be wrong on that.  (My first car was a 62 Chrysler - lap belts only.  The next one was a 72 Dodge Coronet, and it had the two-piece deal.  You snapped in the lap belt, then snapped the shoulder belt to the lap belt buckle.)  So what I'm saying with this long-winded diatribe is that I suspect that the back-mounted steering sector and a good shoulder belt set up will eliminate nearly all of the dangers of the "spearing", all but the most serious accidents, or where the body is not really well secured to the frame any longer.

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Let me say this about the spear.

 

Dad owned a salvage for 30 years, 1960-1990.  I worked for him part time for many of those years.  Parted out a lot of wrecks.  The location of the steering gear has very little to do with the spears effectiveness.  No shoulder harness and the deceleration will propel one's upper chest and/or head into the spear without it moving backward.  No seat belt, same deal, just more of the body makes contact. 

 

In any case, my 56 has the gear ahead of the wheels. 

 

Without gruesome detail, I can attest to plenty of evidence to support the above.

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I put three point seat belts in my 51, but it is a coupe, so not much help.

 

If you look at factory lap belts, such as my 65 Cuda, the floor mount is essentially a doubled up sheet metal arraignment.

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ideas for seatbelts install see:

 

Julianos.com

 

For belts with reasonable prices see:

 

sealtbelts plus.

 

I have used julianos products in the past but there were somewhat  expensive but first class.

 

DJ

 

 

 

 

Universal Aftermarket Seat Belts SeatBeltsPlus.com Street Rod Parts ~ Replacement Seat Belts.htm

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Below is a picture of my 47 with a front steer gen 2 Camaro clip.  I retained the factory collapsible steering shaft and a 70s GM collapsible column.  The steering shaft is not in line with the column.

IMG_2818.JPG.58b8a99ae724a4638566a6bb6ccf4efa.JPG

 

@Eneto-55  No amount of additional bracing will help the B-pillar on a 4 door (if that's what you have).  I could bend that pillar with a couple of good kicks.  A shoulder belt would bend that pillar instantly and loosen the entire 3 point seat belt in the process, that's going backwards from what you need.  This is why modern cars add a pretensioner that pulls the belt tight when airbags deploy.

A 2 door or coupe could possibly be feasible but the roof would have to be significantly reinforced also as it would collapse loosening a 3 point seat belt.

 

In reality, without energy absorbing engineering built into these cars, like modern vehicles, the goal is probably to just not get ejected in a wreck which is why I said what I said earlier about lap belts.  If you're in a major wreck you'll probably be safer to be on a motorcycle, our vintage cars quickly become a meat grinder.

Or buy modern seats with integrated seat belts and reinforce your floor.

 

Oh, life on the edge...  

Edited by Adam H P15 D30
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4 hours ago, Sam Buchanan said:

I agree the way I have my belts attached to the floor doesn't offer the optimum angle. I looked at that for quite a while before deciding everything safety-related about the car was a huge compromise....then accepted the compromised attachment angle.

Just a opinion .... I will start off with I have zero plans for seat belts at this time, I only plan on driving around town at 25-35 mph .... I may change my mind later.

 

IMHO .... If a seat belt works correctly, you will break some bones. The job of a seat belt is to restrain you in case of a violent impact.

That is fine, that is why we have seat belts. They save our life's.

 

ouch.jpg.d4c47ae1a1579aebca703a8e16cc05f6.jpg

 

I kinda think that a lot of engineering goes into proper placement of seat belts. All my injuries, broken pelvic, 3 cracked & 3 broken ribs, 1 broken collar bone, 1 cracked collar bone .... punctured lung. 

All of my injuries was caused from seat belt restraint, they did what they were designed to do. Saved my life .... yeah the air bag helped also.

 

My only point here, A proper lap belt will break your pelvic bone. ..... You have the wrong angle on it, will it slide up & rip out your guts instead?

A proper seat belt will do some bodily harm, the angle will choose where the body gets harmed.

I personally would not compromise  & try to imitate exactly what previous engineers have proven...... you do you.

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13 minutes ago, Adam H P15 D30 said:

@Eneto-55  No amount of additional bracing will help the B-pillar on a 4 door (if that's what you have).  I could bend that pillar with a couple of good kicks.  A shoulder belt would bend that pillar instantly and loosen the entire 3 point seat belt in the process, that's going backwards from what you need.  This is why modern cars add a pretensioner that pulls the belt tight when airbags deploy.

A 2 door or coupe could possibly be feasible but the roof would have to be significantly reinforced also as it would collapse loosening a 3 point seat belt.

 

In reality, without energy absorbing engineering built into these cars, like modern vehicles, the goal is probably to just not get ejected in a wreck which is why I said what I said earlier about lap belts.  If you're in a major wreck you'll probably be safer to be on a motorcycle, our vintage cars quickly become a meat grinder.

Or buy modern seats with integrated seat belts and reinforce your floor.

 

Oh, life on the edge...  

Interesting.  Thanks for your notes about this.   I'll have to look more closely at the top & bottom of the pillar.  (Yes, my car is a 4 door.)  I didn't say here, but I wasn't planning to mount the lower belt attachment to the pillar, but rather inside the seat base.  (Haven't worked out how to do that yet, just my thoughts at present.)  But if the pillar is that weak, then wouldn't the B pillar be pushed all out of place from slamming the doors - both front & back - for over 30 years use (before I bought it & tore it apart)?

 

Regarding the pretensioner - What sort of mechanism locks the shoulder belt when you come to a stop, like on a downhill slope?  (At least it does on my 2010 Grand Caravan.  There's a township road I often use that descends sharply down to a state road, at quite an angle.  I cannot lean forward right away to see up the highway, to check for traffic.  The shoulder belt is locked for a bit after coming to a complete stop.)

 

I do have this advantage - I only weigh around 135. (I'm long in the torso, and come to 5' 10 1/2".)  That's got to make some difference compared to someone who is in the average weight range for someone of my height.

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