Bolt identification

[Karma4all]

Hi yall

Looking to replace new bolts that were pulled out from my Toyota Hiace brake rotor that was screwed against the hub.

Having trouble identifying grade of the bolts. Its got two radial lines on the head marking, but google research showed bolt marking of 3 radial lines only which is a Grade 5. Base on rule of thumb, grade is determine by number of lines plus two, so naturally my bolt is a Grade 4, but it doesnt exist!

Hoping if anyone can help me out here. Image of bolt is below

 

[MintJulep]

Japanese car = metric.

So it will not be an SAE grade anything.

Maybe JIS. Maybe ISO. Maybe proprietary Toyota standard.

Buy replacements from Toyota.

 

[Tmoose]

What is factory torque?

It looks to be in good shape.
On my own vehicle I'd , clean them up (brass, not steel wire brush is my preference) , maybe compare the threads for stretch against some new bolt, put some fresh Loctite threadlocker on the threads, torque it to specs, put the $15 bucks I saved in the beer/college fund and and not give them bolts a a second thought.

Those two lines are not a good match for this alleged factory bolt grade chart.

https://forum.ih8mud.com/threads/toyota-oem-bolt-markings.615066/

 

[monkeydog]

That attachment designates the bolt to be a Class 11T.
The two dashes may be the number 11.

 

[michaelwoodcoc]

I agree with what has been stated before. Just get the replacements from toyota.

It looks like black oxide or some other coating/surface finish. Read up about the specifics in the manual. They may recommend loctite.

That being said the coating is coming off and I'd replace with OEM.

One can notice, working on older cars and motorcycles, when an oem fastener has been reused again and again. Coatings are gone after so many times and they are more prone to sieze.

NGK spark plugs for example use a "release plating" on their spark plugs. Also were the bolts too loose? It looks like the coaring is removed from the bolt where it doesn't even hit the female threads. Was there any corrosion that has already been cleaned up?

Engineering student. Electrical or mechanical, I can't decide!
Minoring in psychology

 

[Kapitonov]

Just go to the market or instruments shop and ask for the same one. Is it hard?