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Topic: Seat belts and Torx Bolts (Read 2912 times) previous topic - next topic

Seat belts and Torx Bolts

Anybody help me out here?
I'm gonna be swaping seat belts in my 86 V8 for the rear passenger seats of my 86 V6 cougar.  But since it's impossible to remove the Torx bolts I've decided to drill them out.  Now what kind of bolt/nut setup should I do when Reinstalling them (Bolts strenth, washers, thread lock?).  (In case I ruined the threads on the chassis to use some new torx bolts)

FYI the passenger belts are usuless in the V8 cougar.  Appearently the belts fell off after the sowed threads were worn off.

Re: Seat belts and Torx Bolts

Reply #1
Definately grade 8 bolts with a lock nut, and grade 8 washers if its not snug in the hole. Why cant you get the bolts out? I used a 1/2" drive torx bit and a pipe and was able to break my rusty ones loose.
1980 birds X 3, 1982 bird, 1984 XR7, 1988 TC

Re: Seat belts and Torx Bolts

Reply #2
I would even think that grade 8 is overkill.  At most how much load could a 300 lbs person put on a seatbelt, even in a high speed collision.  I would definitly use locking washers and red threadlock.

Re: Seat belts and Torx Bolts

Reply #3
Quote from: merccougar50
I would even think that grade 8 is overkill.  At most how much load could a 300 lbs person put on a seatbelt, even in a high speed collision.  I would definitly use locking washers and red threadlock.



awww,, dont put a price on safety.  Besides, grade 8's arent expensive.  besides, a 300 pound person just might weigh 6000 pounds worth of force in a crash.

Re: Seat belts and Torx Bolts

Reply #4
When my mother was in an accident in june, her jacket on her left shoulder where the seat belt goes melted right through, and the seatback snapped where it mounts to the base. Keep in mind she weighs about 170lbs soaking wet, the force exerted on a person in an accident is suprising, especially when the vehicle spins. Besides I think the torx bolts used are grade 8 anyway have that goldish tint to them.
1980 birds X 3, 1982 bird, 1984 XR7, 1988 TC

Re: Seat belts and Torx Bolts

Reply #5
Quote from: tbirdscott
Definately grade 8 bolts with a lock nut, and grade 8 washers if its not snug in the hole. Why cant you get the bolts out? I used a 1/2" drive torx bit and a pipe and was able to break my rusty ones loose.


It's a Canadian Cougar (nuff said?). I'm on the verge of breaking my 2nd Torx Bit (and its the life time gurantee one from Mastercraft)

Now if the bolts weren't exposed to the outside of the car, I'd probably have no probs getting them out, lotta crud on it like rubber undercoating.  I tried heating it with a butane torch but that didn't work either.  I kinda stoped that as Burnt smell of rubber was getting to me.

Re: Seat belts and Torx Bolts

Reply #6
so they put em on the outside of the car in canada?  wow
now i understand perfectly what you are going thru.

try one of these>>>> :macgun:  but aim good and pull the trigger only once

Re: Seat belts and Torx Bolts

Reply #7
Because I have nothing better to do I calculated the force that a person applies on a seatbelt during a crash.
 
Force = Mass x Acceleration
 
170 lbs = 81 kg
30mph = 14.1 m/s
 
Force = 81 kg x 14.1 m/s
 
Force = 1072 Newtons
 
1072 Newtons = 241 pounds force
 
The same weight person going 60 would be about 500 pounds force.

Re: Seat belts and Torx Bolts

Reply #8
Quote
Because I have nothing better to do I calculated the force that a person applies on a seatbelt during a crash.

Force = Mass x Acceleration

170 lbs = 81 kg
30mph = 14.1 m/s

Force = 81 kg x 14.1 m/s

Force = 1072 Newtons

1072 Newtons = 241 pounds force

The same weight person going 60 would be about 500 pounds force.


 :slap:    Nice try, but its time to crack open that phyiscs book one more time.  You just calculated momentum, not Force.  In order to find the acceleration, you need to at least establish an arbitrary value, either for time or for distance.  Since I can better guess distance, I'm going to say about two feet (the amount the "crush" the car will undergo at a 30 mph collision with a solid, non-moveable object, such as a cement wall).

Distance=2ft= .61m

initial velocity=30mph=13.4m/s

Final velocity=0mph=0m/s

acceleration=a

mass=170lbs=77.2kg

to find acceleration:  (Vf)^2=(Vi)^2+2ad

With the #'s above, a=-147m/s^2
Now, using that acceleration and mass of the person, we find force to be F=11,362 Newtons, or 2,554 pounds of force, which is 15 TIMES THE FORCE OF GRAVITY (Gforce of 15 g's)

What makes this force even more dangerous is that it is RARELY parallel with that torx bolt anchoring the seatbelt.  It is usually closer to perpendicular, making it easier for the seatbelt to shear the bolt in half.  In that case, it doesn't matter how many threads the bolt has to support it in the body, it's all about the hardness of the bolt to resist shearing.  Add to the fact that this collision starts and ends in a fraction of a second, and you'll understand the stresses the seatbelt system has to withstand.  At 60 mph, the force of a collision would be much greater than just double the force at 30 mph, provided the crush distance stayed the same.  As we all know, that doesn't happen, so guessing at 60 requires recalculating with a greater crush distance.

Alright.  Class over.  :giggle:

Re: Seat belts and Torx Bolts

Reply #9
Aw , is there gonna be a test on this? :confused:
The Birdman wouldn't lie!

Re: Seat belts and Torx Bolts

Reply #10
3 out of the 4 torx bolts outta the red cougar came out ok, the other one is stubborn as hell and I'm drilling that out. 

The 2 center torx bolts are easy, it's just that the outside 2 are the problem ones,  As there right beside the wheel well...  And Drilling them out is PITA!  And I decided to just use a 3 inch cutter on the donor coug.  Even cutting the top off is a PITA! took me a hour for just 1... (Need a higher capacity air compressor)

Re: Seat belts and Torx Bolts

Reply #11
:flip:
1980 birds X 3, 1982 bird, 1984 XR7, 1988 TC