Hi Everyone
When should the discs be replaced. I have no braking issues except brake wear warning on my ML500.
Thanks

 

Normally the rotors (discs) are replaced at the same time as the pads. The warning, however, just indicates worn pads. There is no warning for rotors, just visual inspection. It's pretty easy, too, to visually inspect the pads. The friction material when new was pretty thick, about 1/2 inch or a little more.

With cool components, use fingers to check for lip at edge of rotor. This indicates how much metal has worn off the rotor. New rotors have no lip. The same lip will exist on the other side that you cannot access to feel. Any lip at all will probably indicate at least 1 mm wear. The wear limit is 2 mm ... remember the other side. There is no refinishing ... the material is gone.

New pads can be installed with old rotors. However, new rotors must be installed with new pads ... so best to do it all. Note: if warning light happens, it means you need new wear sensors, too. When replacing rotors, the caliper carriers are removed from the hub to gain access. New bolts are required when remounting the carriers ... bolts not reusable.

 

Thanks for the advice. Would you say the caliper bushings need to be replaced too?
I've had this car since 2010 and never had to replace any brake part during this time while braking power was perfect all the time. I just changed the brake fluid last year. Ain't it amazing?

 

When the Brake Wear Warning appears it means you must replace the rotors/disks.

 

Would you say the caliper bushings need to be replaced too? Only if they are damaged.

Whether they are damaged or not, lubricate the slide pins with lube.

 

Thanks Major for your guidance.

 

Just the last question Major, are the caliper bolts meant to be one time use and have to be replaced once they are undone? Thanks again.

 

Read steps 6.1 & 6.2 PDF #1..

 

Thank you Major

 

Would you please let me have same information for the rear brakes. I'm planning to replace the rear rotors and pads.
Thanks Major.

 

Here it is.

 

Thanks Major