Bolts & Safety - Please Read!!

[Tools R Us]

I completely agree with everything you said... except this. This is a statement that is often repeated, but simply not true. As per Newton's third law of motion, both vehicles will transfer and absorb equal energy, therefore it will be like hitting a wall at 60 mph. Of course this all depends on the size and weight of vehicle. If the other vehicle is of less mass, you will actually experience the equivalent force of less than 60 mph.
Still extremely deadly, and not trying to minimize what you said; I too hate it when people swap out inferior fasteners, and would never do it.
Just wanted to clarify that.
And now for 100 posts arguing with me....

Agree.

 

[ZeGerman]

I completely agree with everything you said... except this. This is a statement that is often repeated, but simply not true. As per Newton's third law of motion, both vehicles will transfer and absorb equal energy, therefore it will be like hitting a wall at 60 mph. Of course this all depends on the size and weight of vehicle. If the other vehicle is of less mass, you will actually experience the equivalent force of less than 60 mph.
Still extremely deadly, and not trying to minimize what you said; I too hate it when people swap out inferior fasteners, and would never do it.
Just wanted to clarify that.
And now for 100 posts arguing with me....

I don't think anyone is going to argue with you. Lets just be happy that I am not teaching physics or working for NASA

 

[ZeGerman]

A visual reference to bolt markings and their corresponding strength

Tensile Strength: The maximum load in tension (pulling apart) which a material can withstand before breaking or fracturing.

Yield Strength: The maximum load at which a material exhibits a specific permanent deformation

Proof Load: An axial tensile load which the product must withstand without evidence of any permanent set.

1MPa = 1N/mm2 = 145 pounds/inch2

 

[Tools R Us]

As a mechanical engineer who does this for a living (designs bolted joints), this is pretty much a true statement. The reality (like everything in life) is that there is no simple answer and "always use the strongest bolt" isn't the best thing to do. Properly designed bolted joints are complicated. My advice is that in structural applications, always replace a fastener with the same strength that the factory used and torque it per the factory spec. Mr T chose that bolt and that torque for a reason. Deviate from that and you're compromising the strength of the joint.

Also, there shouldn't be any Grade 5s or Grade 8s on a Toyota. That's an SAE spec.

Agree.

Toyotas are built with JIS hardware, so a class 8.8 is close to a SAE grade 5, etc. Specific hardware is also somewhat common, an example would be the brake caliper, marked 11, indicating a fastener that is specially designed for the job. Using the correct hardware and torque is important if you want it to stay together. In most cases, over torquing is worse than under torquing, can plastic deform the hardware, rendering it permanently incapable of holding to spec, if plastic deformed (stretched) the only fix is to replace the hardware. There are several places where hardware is used very close to yield, making correct torque very important, an example would be the cone washer applications.

 

[Lumpskie]

This thread is very timely for me. I'm a new owner of an 80 series. (got it less than a week ago) The other day, I was snooping around, just to see the general condition of what I bought. I noticed that 1 of the 4 bolts that attach the 2nd row to the vehicle, in front, is missing. I haven't removed any of the other bolts yet but, do any of you guys know off the top of your head what size bolt goes in there? Do I need a nut/washer or any other hardware in there? I have no idea whether the other bolts are OEM or not.

Thanks,

 

[Hornd]

Why do school buses not have seat belts?
How do Motorcycles pass crash tests?
Why are car seats not designed like Baby Seats?
Why do Tobacco and Alcohol come with Warnings, but not Big Macs and Bacon?

I used to work in Child Passenger Safety and what you are saying is correct. A head-on crash is not the equivalent of adding the speeds that each vehicle was travelling. But the point of @ZeGerman 's post is still absolutely valid....especially when it comes to securing cargo. Here in the Bible belt you see many people carrying a bible on their rear parcel shelf of their sedan.....the irony is that that book could very well facilitate a meeting with their maker!

Never thought about it, but maybe Chubby Chicks should only go in front seat. Ah put her in the back....They are like Mopeds.

 

[NLXTACY]

Why do school buses not have seat belts?
How do Motorcycles pass crash tests?
Why are car seats not designed like Baby Seats?
Why do Tobacco and Alcohol come with Warnings, but not Big Macs and Bacon?


Never thought about it, but maybe Chubby Chicks should only go in front seat. Ah put her in the back....They are like Mopeds.

Chubby chicks and mopeds, both fun to ride but you don't want your friends to see you on one

 

[davework]

My $0.02 - been dealing with Cruiser Bolts for a number of years, also a Mechanical Engineer, but not in this particular field. I don't disagree with anything that has been said. However, I also think it is fair to say that installing a higher strength bolt (than what was OEM) on a typical automotive installation is going to be a safe bet. And you can almost certainly assume that lower strength bolts were used anywhere possible as cost saving measures as opposed to being more suitable than a high strength fastener, at least in typical fasteners that someone can replace with a Home Depot Bolt.

But, an issue we have is that I haven't seen any reference to what Toyota's Bolt markings (0T-8T) actually correspond to in Tensile and Yield Strengths. Without knowing this, we can't really make a like for like, or better replacement. This is one reason I simply manufactured all my carbon steel bolts at Class 10.9 (Grade 8), but I am guessing the 8T might even be Class 12.9. I may send some OEM Toyota Bolts off to be tested to see what they really are.

I also produced my stainless in A4-70 (just under Grade 5 equivalent) because I didn't like the idea of having that ultra soft hardware store stainless out there to mis-use.

I try to nicely give people flack when I see a stainless bolt holding a seat bracket on in build pics, but it still makes me cringe. I certainly don't sell kits for these applications in stainless or even carbon steel.

 

[Rice]

I completely agree with everything you said... except this. This is a statement that is often repeated, but simply not true. As per Newton's third law of motion, both vehicles will transfer and absorb equal energy, therefore it will be like hitting a wall at 60 mph. Of course this all depends on the size and weight of vehicle. If the other vehicle is of less mass, you will actually experience the equivalent force of less than 60 mph.
Still extremely deadly, and not trying to minimize what you said; I too hate it when people swap out inferior fasteners, and would never do it.
Just wanted to clarify that.
And now for 100 posts arguing with me....

I'll be the first. Newton's 3rd law does not apply to energy. It applies to force. The quantity that is equal for both vehicles is the magnitude of their impulse, i.e. change in momentum, not energy.

 

[mechanist]

Just spent all morning using a bucket of zip ties to secure the spare tire and now this.

 

[nuclearlemon]

Just spent all morning using a bucket of zip ties to secure the spare tire and now this.

should've used bungies. they're great for securing your bumper also.

that said, i'd rather grab anything from the garage than nothing at all. i've seen far too many vehicles like that. a grade five bolt will often be just fine if installed correctly. if you ignore all the penis boy style chat, you have the same kind of warning about driving a lifted rig, or driving without sway bars, or wheeling without sliders. (*#$ happens....you maybe just tempt it more or get lucky. i personally will not spend my life living in bubble wrap in a sterile environment eating quinoa and brussel sprouts and drinking only the purest water.

 

[rc51kid]

About impact speed, you know those crash test videos that destry a vehicle is only a 45mph impact usually.

 

[mechanist]

When I ripped out the interior of my FJ40 in order to strip and seal with Monstaliner, I replaced all the nuts, bolts and washers with John Deere 10.9 grade. Since my teenager drives it as his daily driver, I didn't want anything to break due to negligence on my part. I kept all the old hardware, so do I need to retrofit to the original bolts? I figured since the FJ40 is just a glorified tractor, and since John Deere makes heavy duty tractors, it was a safe bet on their hardware. AND they sell it by the pound. Blows hardware stores away with their single pack hardware for outrageous prices. At the JD store, sometimes they wouldn't even charge me for a bag of nuts and bolts. Great customer service.

https://jdparts.deere.com/partsmkt/document/english/featbene/DKD10018HarwareGuide_Customer.pdf

Thanks for the heads-up on the JD fasteners!


And thanks to @ZeGerman for the ratings schedule above

 

[davework]

i personally will not spend my life living in bubble wrap in a sterile environment eating quinoa and brussel sprouts and drinking only the purest water.

But I like brussel sprouts

 

[LINUS]

...guy installed Recaro seats in 2006 Cherokee. He was rear ended by so called street s**** racer on Subaru.......at over 100kms. The seats, famous Recaro seats broke off the rails. Rails were original Jeep and top side is Recaro. He ended up in hospital...The original lower part was not even buckled, but the top side made by Recaro was ripped off. The quality of the metal it was made was junk.
I also would not recommend installing so called aftermarket sports seats they are worth of s****!!!

....If they were indeed not grey market clone Recaro seats (there are TONS), but that said, there's more to having aftermarket seats than just buy -n- bolt.

Where the problem lies is the integration of the seat shell to vehicle. We talk plenty about not welding a roll cage to your sheet floor without proper plates to spread the weight, but it seems weight spreading in seat bases isn't thought through like some should.

Integrating a aftermarket seat to factory seat base (any brand) without doing the time to build that seat all the way into your floorpan is a bad idea, but luckily we aren't doing G-force situations in an 80 (mostly, unless acted on by another car, trail feature, or flat pushed out the back of a C-130).

A proper set of Recaro SRD's reside in my Sport Evo E30M3 clone, I know they will be safe in all but the worst accidents. I built them myself from the seat base to the floor, using the same seatbelt location (a whole other reason & world) as factory does with the Sport Evolutions did from the BMW assy line.

But back to the boy racer - the closest we have in an urban environment that a racecar design mimicks is NASCAR for the random G-force direction a car can take.
Look there & seats have a welded skeleton (steel or AL, driver pref), added floating pads & bolt to the tube chassis, no sliders as they build to driver size.

Aftermarket equipment is fine, if done right - sadly I doubt your buddy who was rearended would be in a different situation in a factory seat, they design the setups for rapid deceleration & not rapid acceleration to that level. Being rear-ended at a standstill from 75mph isn't the common wreck they design to mitigate.

---Broader takeaway should be that in keeping with proper bolt grades a washer that spreads load is a thought to keep, be it a simple donut or a chunk of plate to spread load like rollcage feet.