Classic cars forum & vehicle restoration.
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Dobbin

Joined: 15 May 2013 Posts: 67 Location: Central Scotland
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Posted: Thu Oct 09, 2014 7:07 pm Post subject: Fitting inertia front seat belts to a 1958 two door Minor |
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Does anyone have any experience of fitting front inertia seat belts to a 1958 2 door Morris Minor. The car in question doesn't have any mounting points at present and a search and results of the web and the MM forums is limited. Ideally I'm looking for pictures or a step by step guide so that I can help the person who asked me if I could help. He has apparently contacted most if not all of the MM suppliers but none of them have been able or willing to provide the necessary information (or at least that's what I've been told) even though they sell the belts. Any help would be appreciated and I can pass it on. |
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Penman
Joined: 23 Nov 2007 Posts: 4857 Location: Swindon, Wilts.
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Dobbin

Joined: 15 May 2013 Posts: 67 Location: Central Scotland
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Posted: Thu Oct 09, 2014 11:04 pm Post subject: |
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Thanks Penman, Yes I had seen that item. I was very sceptical about the bracket and how it was attached. Any ideas or images as to how this bracket was fitted? After all when it comes to safety critical items you just don't get a second chance when it all goes pear shaped! |
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47p2

Joined: 24 Nov 2007 Posts: 2009 Location: Glasgow
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Posted: Thu Oct 09, 2014 11:55 pm Post subject: |
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I suspect one would require some 'extra' metal to be fitted to the bodywork in the vicinity of where the brackets are to be attached
When I bought my P2 it had static belts fitted (no doubt some Australian law) which, if my life depended on them saving my life in a collision I doubt very much if they would have done what they were supposed to, the bolts were tiny and the bracket anchor areas were not strengthened _________________ ROVER
One of Britain's Fine Cars |
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Dobbin

Joined: 15 May 2013 Posts: 67 Location: Central Scotland
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Posted: Fri Oct 10, 2014 7:20 am Post subject: |
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47P2 I'm convinced that 'extra' metal will be required. My main concern is where and how much 'extra' metal.
Looking around the web for pictures, guides or instructions I was surprised how little information relating to this topic that there was. |
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47p2

Joined: 24 Nov 2007 Posts: 2009 Location: Glasgow
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Posted: Fri Oct 10, 2014 10:11 am Post subject: |
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I remember being in my MOT garage a few years ago where they were doing a bit of welding to a VW Polo front belt mountings which were suffering a bit of corrosion. From what I remember the 'patch was about 12" square and seam welded into the area to strengthen the floor up. _________________ ROVER
One of Britain's Fine Cars |
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Old Wrench

Joined: 23 Dec 2013 Posts: 226 Location: Essex and France
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Posted: Fri Oct 10, 2014 10:58 am Post subject: |
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A few points to realise.
Since the universal and mandatory fitment of seat belts, motor manufacturers have had to design floor pans, transmission tunnels etc to take into account such technical and legal requirements.
A car built in 1958 will have suffered significant corrosion of the body structure, thus reducing and weakening the tensile strength of the mild steel.
Seat belt mountings are specified in Newtons (Ability to resist N Newtons of energy).
For the floor or tunnel mounting, one can affix reinforcing steel plates either side of sufficient surface area to act as a "Load Spreader". When designing any mechanical mechanism, one takes into account the expected load to be "Taken Out" by some happening where force is applied.
The Door Pillars are much trickier! The car manufactured in 1958 took no account (as would be normal today) of side-impact crushing loads; let alone a major load stress caused by a small bolt or bolts, retaining an inertia reel seat belt!
Obviously, one could install the belt and "make it look pretty" from a cosmetic perspective. There is now way, however, that existing pillar would "take out" the force it would undergo in an RTA where the belt was trying to restrain 13 stone of human being!
I don't doubt the MM suppliers you mentioned were not prepared to offer any fitting advice! Too frightened of liability; as I would be, too.
A safety starting point is to calculate the potential loads on the inertia mechanism, and then calculate the G Force produced fro, say, 13 stone of person, undergoing a sudden impact which caused deceleration in two feet. e.g. Head On collision.
Some references below; needs good maths though.
http://hyperphysics.phy-astr.gsu.edu/hbase/carcr2.html
http://www.law.cornell.edu/cfr/text/49/571.209
http://www.wired.com/2011/04/crashing-into-wall/
http://www.autoliv.com/ProductsAndInnovations/Documents/Research%20Papers/2.%20Pipkorn,%20Haland,%20Mellander.pdf |
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Bitumen Boy
Joined: 26 Jan 2012 Posts: 1763 Location: Above the snow line in old Monmouthshire
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Posted: Sat Oct 11, 2014 9:23 am Post subject: |
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I accept that our cars often have sentimental as well as monetary value, but if belts are particularly important for this owner might it not be a better idea to sell the '58 Minor and buy a later one that had belts fitted as standard? |
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Dobbin

Joined: 15 May 2013 Posts: 67 Location: Central Scotland
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Posted: Sat Oct 11, 2014 10:00 am Post subject: |
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I accept your comment, but would you sell one of your children or an arm? Ok so a car's neither of these but in this instance selling it is not an option. I know the owner extremely well (no, it's not me). |
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Bitumen Boy
Joined: 26 Jan 2012 Posts: 1763 Location: Above the snow line in old Monmouthshire
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Posted: Sat Oct 11, 2014 2:17 pm Post subject: |
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That's fair enough, but it was worth mentioning all the same. I wouldn't want to sell my Herald either - it would be like selling the dog - but not everyone gets attached to their cars like that.
If your friend is keen to fit belts, it would be worth trying to have a look at one of the later Minors to try and work out how the factory incorporated the belt mountings. Of course a retrofit is an entirely different proposition, but it should at least get the ideas ball rolling. |
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Old Wrench

Joined: 23 Dec 2013 Posts: 226 Location: Essex and France
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Posted: Sat Oct 11, 2014 7:03 pm Post subject: |
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Seat Belts were not fitted as standard (UK) until January 1983.
Retro-Fitting seat belts to earlier cars is potentially an extremely dangerous proposition!
If the height is wrong, the position of the bottom mounting wrong, then they can be potentially fatal.
Consider, please:
http://www.medscape.com/viewarticle/533761_1
I well remember being asked, in 1972, by the local Vauxhall-Opel distributor to drive one of their cars (new Firenza 2.3 Litre "Droop Snoot") in a local autocross meeting as part of their local advertising.
The field on which the event was held was extremely rutted and bumpy and at 70+ down the straight bit, the car was taking off. And each time it did the almost new factory set belt loosened dramatically!
At this time I was used to a proper full racing harness: and in single seaters, at this time, the Willlens Fast Pursuit Jet fighter pilots harness which included crotch straps and the shoulder and lap straps three times as wide as a conventional production car harness, were ubiquitous in formula cars.
I found the Firenza rather worrying; in the event of serious RTA, significant deceleration with such a loose belt would cause a broken neck, probably.
I am just saying be very, very careful with retro-sitting belts in older cars.
Or don't buy anything much before 1983! |
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colwyn500
Joined: 21 Oct 2012 Posts: 1745 Location: Nairn, Scotland
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Posted: Sat Oct 11, 2014 7:54 pm Post subject: |
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Seatbelts in the outer front seats of UK cars were compulsory from 1968; it is the use of them that became compulsory in 1983. The legislation meant that cars built from 1965 had to be retrofitted so at a a guess, I expect cars would have started to be fitted with anchorage points, at least, from 1965.
I agree with Old Wrench and would say that there is little point in providing the feeling of security and having done something for your childrens' safety when you might actually be creating an extra layer of danger. |
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Old Wrench

Joined: 23 Dec 2013 Posts: 226 Location: Essex and France
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Posted: Sat Oct 11, 2014 9:02 pm Post subject: |
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There was an early French study on seat belts, which showed a high incidence of serious spinal injuries and broken necks; I cannot find this now.
Seat belts seemed to be rushed into use as governments and the Do-Gooders started their campaigns against the dread motor vehicle.
One thing that has always concerned me, is the singular fact that lap and diagonal belts are invariably fitted with one standard top mount: yet human beings come in all sizes and weights......
Ergo, there is a huge difference between, say, a man of 15 stone who is six feet two and a lady of eight stone of five feet two, reference the actual contact point on their torso. |
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Penguin45

Joined: 28 Jul 2014 Posts: 384 Location: Padiham
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Posted: Sat Oct 11, 2014 10:01 pm Post subject: |
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That logic would imply that it's better to be dead than injured by wearing some sort of restraint. Fitting static belts at the time was only the starting point. It didn't take long for inertia belts to come along and adjustable top mounts, via the "shorty clip", eventually arrived.
My 18/85 being a MkI had no rear belts fitted, and no mounting points. Given that I couldn't drive small children around without belts or booster seats, I went and looked at a MkII belonging to a fellow club member, located and measured the bracketry and plates in that car and made and welded them into mine.
I can see no reason why the OP shouldn't undertake the same process with his Minor.
P45. _________________ '67 Wolseley MkI 18/85, '70 Austin MkII 1800 The Landcrab Forum. |
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Old Wrench

Joined: 23 Dec 2013 Posts: 226 Location: Essex and France
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Posted: Sun Oct 12, 2014 11:44 am Post subject: |
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Penguin45 wrote: | That logic would imply that it's better to be dead than injured by wearing some sort of restraint. |
Sorry, I disagree. Obviously in an RTA involving certain moments of force (Sideways Impact) a seat belt over no seat belt can result in zero serious injury with no seat belt and serious internal injury with an incorrectly fitted belt.
"The bodyshell was exceptionally stiff with a torsional rigidity of 18032 Nm/degree, this was greater structural rigidity than many modern cars up to the end of the century.[3]"
Interesting the car you own enjoyed the greatest mass production unitary body torsional rigidity of structure, probably not exceeded until 2000!
The Morris Minor did not, however......
References of interest:
http://www.car-seat.org/showthread.php?t=230467
http://www.quickfitsbs.com/
Plus a very useful resource on the 18/85 et al.
http://copeland.id.au/wp-content/uploads/2010/05/Austin-1800.pdf
If the OP's chum is really serious about this, then I suggest he/she consults Bill Quick's company (Above). |
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