[chrisd0729]

I tried replacing my rear brakes today and had issues returning the piston. I have the tool to turn it back in and turned it clockwise about 5-6 turns while pushing in on it. It didnt collapse at all. I turned it another few turns and it tightened a bit.... still not collapsing at all. I had to put it back together and leave the old pads on it.

Anyone have ideas on whats wrong and how to fix it? The dealer wants $999 to do rear brakes with rotors but i can easily do myself if i can collapse the piston.
Thanks

 

[Jmpacker]

Did you set the car to e-brake service mode?


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[chrisd0729]

Did you set the car to e-brake service mode?


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The few threads i read on here said we didnt need to do that for 2014 rear replacement. Do I need to do that?

 

[Jmpacker]

I just completed a front and rear brake change on my 2016 L494 RRS. I put the car in e-brake service mode first so I can’t answer whether you can complete or not without setting this mode. I think not. One side I had to turn back and compress the other side compressed easily. FYI- I came across the e-brake service mode purely by accident as there is little info on DIY fir this model. Good luck.


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[383vett]

I just completed a front and rear brake change on my 2016 L494 RRS. I put the car in e-brake service mode first so I can’t answer whether you can complete or not without setting this mode. I think not. One side I had to turn back and compress the other side compressed easily. FYI- I came across the e-brake service mode purely by accident as there is little info on DIY fir this model. Good luck.


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Can you elaborate on how to set the e-brake service mode. Thanks.

 

[GPS]

You have to activate an e-brake service mode... Procedure is as follows:
- Turn the ignition ON (not the engine) by pushing the start/stop button without stepping on the brake pedal
- Push the e-brake button down for 2 seconds and hold it (release the e-brake)
- Push the accelerator pedal down for 2 seconds and hold it
- Push the start/stop button twice (turn the ignition off and on)
Now the e-brake service mode is active.. you will hear a noise from the rear e-motors, when its releasing the e-brake to the service mode. Still hold the e-brake button and the accelerator pedal.
After the e-motors stops there will be info on the dash that the e-brake service mode is activated.


To deactivate the service mode is the same procedure, the only change is that you have to pull the e-brake button

 

[383vett]

That's good info. Thanks

 

[chrisd0729]

Great info, thanks! Would the car NOT being in ebrake maint mode cause the issue I had? Would that prevent the piston from turning in?

You have to activate an e-brake service mode... Procedure is as follows:
- Turn the ignition ON (not the engine) by pushing the start/stop button without stepping on the brake pedal
- Push the e-brake button down for 2 seconds and hold it (release the e-brake)
- Push the accelerator pedal down for 2 seconds and hold it
- Push the start/stop button twice (turn the ignition off and on)
Now the e-brake service mode is active.. you will hear a noise from the rear e-motors, when its releasing the e-brake to the service mode. Still hold the e-brake button and the accelerator pedal.
After the e-motors stops there will be info on the dash that the e-brake service mode is activated.


To deactivate the service mode is the same procedure, the only change is that you have to pull the e-brake button

 

[GPS]

Yes, correct.
The piston will not move, you need to create heavy pressure at this point to make the piston going in.

 

[RangeR-Over]

I did all 4 corners on my 2015.5 MY and they turned in easily. I am just hearing of the "E-brake service mode" for the first time. Hope I didn't hurt anything... though it's been 2 months so i think I'm ok.

 

[drrange]

Recently replaced my rear brake pads on my 14 HSE. Turned the passenger side in twice after receiving the wrong pads initially (once w/o and once with the service mode engaged) and did not notice any difference. The pistons on both sides were difficult to turn in even with the correct caliper compression tool. Not sure if later years are different, but the piston compression resistance was the same in both modes on my 2014