Bimmerfest - BMW Forums - View Single Post - How to check & replace your BMW front disc brakes and rotors
View Single Post
Old 03-26-2008, 07:22 PM
bluebee's Avatar
bluebee bluebee is offline
Seek to understand,^Value
Location: San Jose, California
Join Date: Mar 2008
Posts: 25,236
Mein Auto: 02 BMW 525i M54 auto 130K
What does the tangental cut in rotor edge indicate?

Thanks for the Final Stage Unit (FSU) "hedgehog" advice (aka porcupine resistor); I'll also look at the fuse deeply behind the glove box according to that article. My fan isn't "posessed" so much as it's just not working ... so I'm not sure if the FSU is the culprit but it seems a commonly failed part based on that article that it might be the cause of my fan stopping all of a sudden and not something I did when I cursed at that horrid air-cleaner box setup!

Back on topic for the BMW brakes DIY, can someone edify me as to why there is a "slit" in the side of the old and new rotors?

This slit seems, upon first glance, to be a wear limit grooved into a tangental slice of the rotor; but, the fact that my clearly worn (as measured by the "inchometer") front rotors still had much metal above the slice, makes me wonder.

Is the slice to indicate a horribly gone you're-gonna-die thickness of the rotor? If not, what does the rotor slice indicate?

Attached Thumbnails
Click image for larger version

Name:	bluebee_slits_in_rotor.jpg
Views:	14779
Size:	48.3 KB
ID:	141375  

Last edited by bluebee; 03-26-2008 at 07:24 PM.
Reply With Quote