Are Hex Bolt-less Rear Discs/Rotors Dangerous?

[dlguadiz]

I recently purchased a second-hand rear disc brake (as my rears are super thin). But there is a problem: my Inner Hex Bolt (Part #34111123072) goes thru it and does not hold it down. Upon inspection, the slot that accommodates the bolt was apparently removed... see following pictures:

1. My original disc brake... note that the hex bolt hole is slotted

20220826_190405.jpg

2. Original disc brake with hex bolt (#34111123072) seated on the slot, as it should be...

20220826_190330.jpg

3. Newly bought second-hand disc brake with large hole, no slot, and hex bolt goes thru it.

20220826_190432.jpg


So essentially, the rear disc brake will be held in place by the Wheel Bolts/Lug Nuts themselves, not the hex bolt. Is this dangerous? Why or why not?

This is the braking system so my first reaction is not to use them/return them.

[Mikealwa]

Most cars don't use a screw to hold on place, I think it makes no difference. Lug nuts are torqued to around 85 ft lbs, that screw is torqued to like 15 ft lbs maybeee. I think it's fine.

[dworthy]

Naa, don't worry about it, for the whole idea behind the hex bolt is to hold the rotor in place is all, nothing more.

[nick325xit 5spd]

The only thing it does is potentially make wheel swaps more annoying - the rotor might turn and block holes. It's totally unnecessary if you have studs.

The screw is just for convenience.

[95BMWIC]

AS others have stated - no real safety issue with not having a set screw in. I broke the head off mine many years ago and have not fixed it (extracting or by replacing the hub)..
It is annoying putting in the lug bolts in at times, if the rotor is not lined up - but once the lug bolts are tight everything is secure. .