We're told in the videos that the spacer keeps the pistons the exact distance apart during the bleeding process.
Was just going to make one out of something in the garage, but don't know how thick it should be? Any ideas?
The yellow spacer that came with mine is 10mm wide.
Too narrow.
I prefer pads set closer to discs than the Spacers allow
I made a narrower one out of a piece of wood. Panel pin in the top to aid putting it in / pulling it out works a treat.
I've got the spacers that came with the brakes, but they're only the thickness of the rotor.
The one in the video looked a lot thicker.
I would put a link to the video but I'm useless.
The ones the thickness of the rotor (thin red ones) are for using with the brake pads still in when the wheel is removed to protect from applying the brake accidentally.
The thicker one (yellow) used in the bleeding video is the 10mm wide one which is used with pads out to set the distance in the space between the calipers.
Definitely 10mm, which is why you can just drop a 10mm Allen key in the slot to do the job.