Broken Caliper bolt

[WIZ929]

I was changing my rear brakes and the caliper bolt broke didnt know i was that strong
does any one know of an online store where I can just get the bolt my local autozone does not carry it
thanks

[porcupine73]

Is this the bolt holding the caliper bracket to the wheel bearing housing (front), or backing plate (rear)? These bolts are a dealer only item. I did find a match at Ace Hardware, it's a metric 8.8 (similar to SAE grade 5), whereas ideally it would be a metric grade 10.9 for brakes.

[WIZ929]

thanks i found one at home depot

[porcupine73]

Cool. What grade fastener did you find there?

[Boxxerace]

I would recommend hunting down the part from a scrap yard or a good bolt supply place (aka: not lowes / home depot) if in fact grade 10. something is standard. Grade 10 (if it exists) should be a rigid, more brittle steel.

[porcupine73]

It probably doesn't matter, but on something safety critical like brakes high quality high strength fasteners are preferred. There's a reason low strength fasteners such as SAE grade 2 are often used as shear pins.

Many Subaru fasteners are metric flange bolts. Subaru fasteners are hard to figure out the grade. Often they just have a number on them like '7'. This is probably some Japanese or JIS standard.

Grades 8.8 and 10.9 is typically found on metric fasteners in the US. SAE grades 2,5,8,9, etc are often for inch fasteners. But metric grade 8.8 is similar to SAE grade 5, and metric grade 10.9 is similar to SAE grade 8.

There's some basic fastener grade/material info here from mcmaster.

[Boxxerace]

Thanks Porc. You know your stuff!

[porcupine73]

The other thing is a lot of the Subaru critical fasteners are considered fine or extra fine thread pitch in their size which can make them even harder to find suitable replacements.

A weaker fastener might work fine in the application. But the time it may fail is when it has the most stress on it - such as a panic stop.

The material and coating is important too. Some of the brake fasteners have some sort of armor coat or cadmium or something on them. A simple zinc coated fastener may not hold up to corrosion as well.