2015 rear brake disc - Torx screw

[lamuncha]

Can someone help me with the purpose of the Torx bolt brake disc screw that threads through the face of the disc into the hub? I am going to replace a disc - the manual reads - remove the brake disc screw. Thread a M10 bolt into the brake disc removal hole and tighten to press the disc off the hub.
I am not sure how threading in an M10 would force the disc off the hub. Unless the hole in the disc is M10 size and the bolt threads into it and forces the disc off.

I'm aware of thew BF hammer method but not a big fan. I am curious about the purpose of the screw.

Thanks

 

[Adrian Gitch]

I believe that screw was just meant to hold the rotor on during assembly at the plant.

 

[peterk9]

I'm not a mechanic but it sounds like you may have answered your own question. " Unless the hole in the disc is M10 size and the bolt threads into it and forces the disc off ".

Peter

 

[peterk9]

I believe that screw was just meant to hold the rotor on during assembly at the plant.

I think that was just for the front brakes if I read the thread on that correctly.

Peter

 

[Bcizme]

If it is like other cars I have changed the brakes on, when you thread that M10 bolt in it will push the rotor off the face of the hub, which makes removal easier. Just make sure you have a grade 8 or similar bolt to use. Sometimes they pop right off sometimes you need to work it a little. You may need to screw the M10 bolt in and put some tension on it and then use your BFH to tap on the center of the rotor, not the wear surface, and the shock will sometimes help the rotor break free as well, but the bolt in that hole does help when designed for that. In some other cars the torx bolt is there is simply hold the rotor on as other has mentioned. But the rear brakes the BFH method can be difficult due to the brake shields and inability to turn the wheel to get a better angle on it. Also if they are stuck good, as we see in NY due to the rust you can spray penetrating oil in that hole to help.

 

[boominXplorer]

Just like said above. The bolts that hold the rotor on are just that. When you see threaded areas in a rotor hat then you can usually screw a bolt in to push the rotor off the hub face.

If for some reason you strip out or loose the bolt that holds the rotor in place it's not really necessary. It basically helps keep the rotor on when installing pads, the wheel studs / lug nuts hold the rest.

 

[gatzdon]

Depending on where you live, the amount of corrosion fusing the rotor to the hub varies. If you have even a moderate amount of corrosion, threading a bolt through that hole won't do anything but make you more frustrated.

Best practice is to hit the rotor with PB Blaster through the lug stems and around the hub. Let it sit for 15 minutes. Then while someone rotates the rotor, gently/consistently tap the backside of the rotor with a hammer until the rotor breaks free.

If you live in the Midwest, this could take up to an hour due to the massive corrosion, but it will save your bearings from getting damaged.

When replacing the rotor, liberally coat the hub with anti seize compound and you will never need the hammer again.

The torx screw is good for holding the rotor in place during reassembly. Technically it's not needed, but does make it easier.