Sorry. I’m used to having specifications that specify everything you need to know about a part. Toyota coming up with their own standard for bolt strength is very frustrating. What a way to to prevent people from just going out to a hardware store and buying replacement bolts! How awful of them. I’m hesitant in replacing any fastener without knowing it’s specification and making sure I’m replacing it with an equivalent bolt.
I figured I would let people know who might also be reading this and wondering what the answer is. It seems lots of people have this questions but never got an answer.
I know the specification the bolts are built to! It’s a good read. I read stuff like this all the time everyday.
It’s Toyota Engineering Standard TSB1001G Toyota Engineering Standard that well tell you everything you want to know about the Toyota standard for their unique markings on the head of their bolts! Good grief, what a pain! But at least with the specification it clear up any confusion! It’s a good read for anyone who wants to read it.
Also for anyone else who’s reading this. I found the answer on if you should or shouldn’t switch out your fasteners to stainless steel ones or other types. The answer is NO! The strength ratings for the bolts that come installed in vehicles is either to ISO R898 standard (example Class 10.9) or SAE J429 standard (example Grade 8) or in the case of Toyota their own standard TSB1001G (example 4T). These standards are strictly for steel type bolts! While replacing them with stainless steel seems like a good idea, it’s not! Stainless steel bolt strength ratings are to the ASTM A193 standard (example B6).
Now comparing the ISO R898 specification to the ASTM A193 specification
Example I want to replace a ISO R898 Class 10.9 bolt:
Proof Load (psi) = 120,000 psi
Yield Strength Minimum (psi) = 130,000 psi
Tensile Strength Minimum (psi) = 150,000 psi
There is not a ASTM A193 bolt that comes close to these ratings. The ASTM A193 standard also does not have a proof load rating. So the two specifications are not comparable.
That’s some good info. Thanks for researching and posting it.
I had never realized that Toyota (and perhaps other Asian makes) had their own bolt grading system.
If you need stainless bolts with higher strength specs than shown in the A193 chart, they are available, but you’d have to go to specialty bolt manufacturers, such as ARP Bolts. ARP’s “stainless 300” material is rated at 170,000 psi tensile strength. These bolts would be fine in low stress “dress-up” applications where corrosion resistance and appearance are more important than strength. Determining what high stress applications this material is suitable for would require consultation with the manufacturer.
Does anyone have a guide on which strength steel bolts (example 10.9) can be replaced with which grade Bumax stainless steel bolts? Apparently some grades if Bumax stainless steel bolts are as strong as steel in terms of tensile and yield strength.
Why did you revive this old nonsense thread ? If you want that info contact the manufacture .
I am beginning to thinkl you are a Troll with all these weird questions .
10.9 IS the grade. It is a universal measure of the bolt’s strength.
Bumax grades show "88* and “109” which likely mean 8.8 and 10.9 but you’d have to compare the listed strength with those listed minimums for 10.9 and 8.8 to be sure.
I’m going to point out that continually haranguing people, especially relatively new ones, because you dislike the fact that they had the unmitigated temerity to ask questions on a forum set up for people to ask questions, is itself trolling.
This site does, as most sites, have a learning curve.
Not everyone realizes they can start a new thread.
I, along with other, have responded to a new post without noticing the original post was many years ago.
To me the above question and response was informative.
We disagree some but I’m with you on this. Sometimes engineers should just go to a hardware store or take the car to the dealer and have a cup of coffee.
