Bolts & Safety - Please Read!! (1 Viewer)

[ZeGerman]

I have been tearing into my cruiser. Took the entire interior apart as well as other parts of the vehicle. I have been tearing apart vehicles for quite sometime and there seems to be one thing that I encounter all too frequently. Usage of inadequate bolts.

Everybody on this site likes to tinker and change and upgrade etc. In every vehicle I have torn down, I notice that the bolts used are not adequate. Just because it seems strong enough and is thick does not mean that it will hold under all circumstances.

I would like for all of you to take a circumstance that I pray and hope will never happen to any of us. A head on collision. Scary as hell. Say you are driving a gingerly 60mph and a car in the opposite lane also driving sixty but not paying attention veers into your lane and you get into that dreaded head on collision. Thats the equivalent of driving into a wall at 120mph!!! Sudden stop. Now think of all the stuff in and on your vehicle. A fire extinguisher on a plastic clip in the trunk? A large Maglite on a clip? A big fridge in the back? You get the point. All items including the occupants will become projectiles! You get hit by anyone of these things, ITS OVER!! LIGHTS OUT FOR YOU AND OR YOUR LOVED ONES!!!!! Can you imagine anything worse?

I had seats that were bolted on half with factory bolts and the other half was some sub par piece of crap bolt found in a jar in the garage. You would never zip tie your tires onto the truck then why would you use sub par bolts? No way that these things will hold in an accident. You can have the absolute best child carseat in the world, but if the seat itself does not stay put, that will not help you one bit!

Also please check your seat belts. Yank on it. If it does not stop immediately, its a piece of s*** restraint system that will not do you any good. Fix it or replace it. If you are unsure, then have someone who knows what they are doing look at it.

Look, Im not going to get into the different grades of bolts. You can do a simple google search and find out for yourself. But please, I implore each and everyone of you to check the pertinent points of your vehicle and switch out the weak bolts etc for something that is well beyond the strength recommended. We spend so much money on accessories like bumpers and tires and suspension, whats a few bucks to get decent hardware to keep yourself and your loved ones safe.

JUST REMEMBER WHATS AT STAKE AND NOT THE ODDS OF ANYTHING HAPPENING!

 

[richardlillard1]

I don't understand. Are you saying that the factory bolts are subpar, the replacements are junk, or both?

 

[IdahoDoug]

Standing ovation here. Well put. None of that fastener stuff matters.............................until it does. As stated, loose stuff in a car kills and part of his message was to secure that stuff well. Got a tool box back there? Motorcycle strap it down and put the strap THROUGH the handle and crank it down like you mean it. Headed out on a camping trip and have the right stuff in the back - axe, come-a-long, shovel, cooler with an assortment of glass bottles, metal cans, and the like? Throw a canvas tarp over it all and motorcycle strap it down. You drive a well built tough truck that will give up crush space only grudgingly in a severe crash to save your life, but a full beer can to the back of the head in a crash will have you drooling and wearing Depends the rest of your non-Cruiser driving life.

 

[ZeGerman]

I don't understand. Are you saying that the factory bolts are subpar, the replacements are junk, or both?

Factory bolts are fine but the other bolts used were a grade 2 bolt. The point I am making is not to criticize each bolt that was used on my rig, but for everyone to be conscious of the hardware they use.

And FYI, Just because something is factory supplied, does not mean its of great quality all the time. Car makers are in the business to make money. Thats it! They have bean counters that will subtract and minimize the cost until the profit margin is just right.

For less than a cup of coffee you can get grade 8 bolts. Why not use it.

 

[Jason hansen]

When in doubt, use grade 8 when modifying.

 

[ZeGerman]

When in doubt, use grade 8 when modifying.

YESSSSSSSSSSSSS!!!

 

[1973Guppie]

Factory bolts are fine but the other bolts used were a grade 2 bolt. The point I am making is not to criticize each bolt that was used on my rig, but for everyone to be conscious of the hardware they use.

And FYI, Just because something is factory supplied, does not mean its of great quality all the time. Car makers are in the business to make money. Thats it! They have bean counters that will subtract and minimize the cost until the profit margin is just right.

For less than a cup of coffee you can get grade 8 bolts. Why not use it.

I am not a metalurgy expert but I thought I have heard that in certain situations a grade 5 bolt if preferable as it will stretch some and not break like a grade 8 bolt as it is more brittle. Again, just remember hearing this off the top of my head, not sure if it is true or not? and discuss.......

 

[ZeGerman]

I am not a metalurgy expert but I thought I have heard that in certain situations a grade 5 bolt if preferable as it will stretch some and not break like a grade 8 bolt as it is more brittle. Again, just remember hearing this off the top of my head, not sure if it is true or not? and discuss.......

Bolts are graded according to the following properties:
1. Proof Load PSI
2. Minimum Yield Strength PSI
3. Minimum Tensile Strength PSI

Grade 5
1. 74,000 PSI
2. 81,000 PSI
3. 105,000 PSI

Grade 8
1. 120,000 PSI
2. 130,000 PSI
3. 150,000 PSI

My initial thought is to always go Grade 8 but if there are instances where Grade 5 should be used, then I definitely want to hear about it. All these members on mud there must be at least one metallurgist on board. Maybe @NLXTACY can enlighten us better.

 

[NLXTACY]

Don't look to me for enlightenment for I am not enlightened.

Machinery's Handbook is what I reference as often as I can.

In tension/shear, grade 8 bolts are stronger than grade 5. Period. This is of course going by the SAE standard vs the Metric standard. For a given load, any steel bolt (grade 8 and grade 5 or grade anything) will stretch the same amount, up to its yield strength/elastic limit. Remove the load, and it "unstretches" back to its original length. For a grade 8 bolt, this load/stretch is greater than a lower grade.

Above the yield strength, the stretch increases dramatically with very small increases in load, until the ultimate load is reached. The ultimate load is higher for a grade 8 bolt than it is for a grade 5. If you stretch a bolt beyond its yield limit, it will not return to its original length.

Softer steels will stretch more than harder ones before they break, but the actual load at the break point will still be much lower for the soft steel.

Then there's fatigue strength. Bend a piece of metal back and forth a bunch of times; it may not break right at first, but it will break eventually. For any given metal, there is a fatigue limit, which is lower than the ultimate load. Below the fatigue limit, bend it as many times as you want and it won't break; above that, it will eventually break.

Finally there's impact loading. This is tested by notching a steel bar and hitting it with a hammer, precisely. This is the one case where a softer steel might do better, as harder materials tend to be more brittle. However, for most of our applications it's not that important (unless you're trying to snatch a stuck Jeep out with a chain instead of an elastic nylon strap), as the suspension tends to damp out and spread loads below the sharp spike necessary for impact failure.

Also, even grade 8 bolts aren't all that brittle; after they're heat treated to get the ultimate strength up they're tempered to bring back the impact strength. Impact strength might be an issue if something's loose, so that it shifts and bangs around before it hits whatever is stopping it (i.e. the loose bolt).

So... grade 8 bolts are stronger in virtually any application. Whether you need that strength, and want to pay extra for it, is another issue. There may also be situations where you may want the bolt to fail before the expensive part it's holding breaks, but maybe that IS the issue.

 

[ZeGerman]

Don't look to me for enlightenment for I am not enlightened.

Well s***!! If you are not enlightened, then I am but a mere polished turd

 

[NLXTACY]

Well s***!! If you are not enlightened, then I am but a mere polished turd

I regurgitate

 

[Rifleman]

I ran across this very problem while working on a front brake caliper. It seems that sometime in the past, a shop did brake work on my friends LC, they replaced what was a grade 8 bolt, with a grade 5. We found this out when we went to torque the caliper mounting bolt to 100 Foot Pounds. We were not able to get past 65 foot Pounds when the weaker bolt snapped in two. Just stop to think if that weaker bolt had failed while going 70 MPH. Sad to say, but some repair shops just don't care anymore, it's all about getting the truck out the door.

 

[LINUS]

I regurgitate

These days it ain't what you know as much as managing the sources of info.

But if the power goes dead or google craps out, paper copies > anything else.

And when it comes to the hardware game it's nice being a owner who's seen near every conceivable bolt, nut, and clip on my 80.

As for unsecured cargo, a very lucky boy who totalled a car thought his big heavy speakerbox would "stay put on its' own" - he was lucky he hit an off angle corner as it went through a Suburban rear window & landed ~25' away from his car.

I see strange things like that from the ambulance ride time, things we who do trails take for granted. I seem to recall Mythbusters put a simple can of shave cream in a rear deck & measured it could paralyze you if it could hit your C section vertabrea.

It was something as light as that, it's been years. I always think of that though esp with the Tundra Crew Cab - I make sure to try & put stuff like groceries on the floorboard.

And the dog wears a real harness (has the TUV logo, the buckles are steel x4 & has steel pickpoint) & he has a leash I have on a legit climbing 'pear' carabiner. I've never been to a dog passenger wreck, but a ~60# boxer going airborne is not a story I want to hear the end of.

 

[Tugarin]

Very true, I know a guy who installed Recaro seats in his 2006 Cherokee. He was rear ended by so called street s**** racer on Subaru, he was parked static and the guy rear end him 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 with back injury. 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****!!!

 

[IronCladLou]

I am not a metalurgy expert but I thought I have heard that in certain situations a grade 5 bolt if preferable as it will stretch some and not break like a grade 8 bolt as it is more brittle. Again, just remember hearing this off the top of my head, not sure if it is true or not? and discuss.......

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.

 

[SeaWheezl]

I would like for all of you to take a circumstance that I pray and hope will never happen to any of us. A head on collision. Scary as hell. Say you are driving a gingerly 60mph and a car in the opposite lane also driving sixty but not paying attention veers into your lane and you get into that dreaded head on collision. Thats the equivalent of driving into a wall at 120mph!!! Sudden stop.

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....

 

[mstakacs]

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

 

[Malleus]

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.

What he said...

 

[NLScooby]

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 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!

 

[SeaWheezl]

I agree 100%
My wife got rear ended in a minivan by a full size truck at about 35 mph. It was pretty amazing and scary to see where items in the vehicle ended up.