18-09-18, 10:47 PM
Quote:Anyone know the purpose of said marks? Do they need to align with the slit in the disc?
No, the bobbins are there because of the "floating brake discs" which allow the actual disc to move in relation to the inner to stop it warping if it gets hot due to serious use.
The bobbins should actually be able to revolve, it's a good idea to check them occasionally. Get a nut and bolt that will fit through the hole, tighten it enough that it grips the bobbin, then try to get the bobbin to revolve. If it doesn't, spray it with some brake cleaner (DON'T use anything lubricating, unless you want to risk your brakes not stopping you at all!) and it should eventually shift.
Here's a video that may help. The useful bit starts at 2'30"
https://www.youtube.com/watch?v=1qoPqN2GBdw
If you're going on a track day and going to be doing heavy braking, this is well worth doing, rather than risking warping a disc!