MBWorld.org Forums - X166 2013 GL450 Unusual Brake Wear 10k Miles

X166 Owner. 2013 GL 450. I have a problem that is not normal brake wear.

Front pads have 36k miles on them and look like they are less than 50% worn. 1st set of rear pads lasted 30k. Found OUTSIDE right rear passenger pad was down to metal. Wear sensor was mounted on INSIDE right rear passenger, inside pad was 60% worn while it's outside partner was down to metal. Replaced all rear pads and rotors (Textar OEM Pads, Zimmerman Rotors), all premium parts.

10k miles later, rear passenger OUTSIDE pad was toast again, down to metal. Inside pad 50% on same wheel. I noticed the rear rotors are both noticeably hotter than front pads after only driving even 10 mile. I've read on this forum that the world of auto engineering has changed, and the rear now wear faster than front. Ok. Replaced pads AGAIN at 10k with clear uneven wear. Extra careful to clean calipers, caliper pins, boots, brackets, slide groves, and properly lubricate all with high quality brake part lubricant.

Decided to keep electronic parking brake DISENGAGED in case it was causing a dragging on the rotor. Noticed less heat on rotors with electronic parking brake disengaged, but still noticeably hotter than front rotors. When I turn electronic parking brake back on, not set to park of course, rear rotors are noticeably hotter after short drive. This is aggravating.

Can be one of 3 things, or combo:

1) Both rear brake calipers sticking? Somehow passenger rear is worse than driver rear, not sure why it would stick and wear outside pad, but not inside?

2) Brake hoses bad and not releasing back pressure to brake master cylinder, keeping brakes engaged/touching? Hoses 5 years old, fresh looking, proper shape and form, not collapsed or worn in any way. Applied pressure to rear brakes and released, then loosened brake bleed nipple, no high pressure spray or spurt typically means hoses are working correctly - therefore not blocked or holding pressure between caliper and hose.

3) The electronic parking brake is not fully releasing and is someone dragging/touching pad constantly? Again, why passenger only outside pad getting eaten up? Does it use the passenger side rear exclusively? Again, noticed less heat on rear rotors with electronic brake completely disengaged, standard braking function still works.

Any input welcome. I've been working on cars most of my life. I'm not Mercedes Certified for sure, but I fully understand how to use the electronic engage/disengage feature via onboard computer - in part thanks to contributors to this forum. I own two Mercs, a 2003 W211 185k, purchased new in Summer 2002, yes I've owned it for 16 years. And a 2013 GL 450 purchased as local Certified Preowned with 30k miles on lease turn-in.