Maintenance mode makes it so you don't need to compress the piston.

 

So, actually this is incorrect. After taking the caliper apart, it is obvious that the EPB is not physically attached to the piston. The EPB actuates a secondary piston that is captured internally by the main piston. This secondary piston is able to extend the main piston body and hold the brake pads against the rotor but is not able to retract the main piston. When the EPB disengages, the secondary piston that is internal to the main piston simply retracts by a threaded rod away from the main piston, leaving it in place. Through some research of my own I have come to understand that the square-cut seal along with a specially cut groove is what performs the retraction of the piston to release the brake pads from the rotor. Although, this retraction is only around 5 thousandths of an inch (0.1 mm). So, even though you engage maintenance mode which retracts the EPB, it does not retract the piston and you still need to compress the piston to allow for the new thicker brake pads.

Here is some information on the operation of the piston due to the square-cut seal and groove:
Checking Caliper Piston Operation
Patent US20090272606 - Triple chamfer seal groove - Google Patents

 

Just a quick update. One of the rear dust boots had a tear so I am rebuilding the caliper on that side. Now that I have the caliper apart I see how the EPB is able to extend the piston. If anyone is curious to see pictures of a tear down of a Mexico build rear brake caliper for a 2017 Mazda 3 sport with an EPB, let me know.

 

May want to do more research..

 

I agree. I did rear pads on my 2019 and I did not have to turn or compress the rear piston after enabling Maintenance Mode to fit the fresh pads and rotor.
The 2019 is a 4th Gen Japan build, but I suspect that the EPB is the same basic system as a 3rd gen Mexico build.

Your information regarding the normal retraction being done by the shape of the seal and groove, however, is correct. Interesting, yes, but irrelevant to this discussion.

 

Maintenance mode did not require additional piston compression on my 2018 the three times I've done it.

 

I go with EBC aftermarkets. Seem to work okay.. I just do a ton of canyon runs that required replacement.

 

Agree completely, I've had the same problem with every set of pads I've put on my car (2016 3 Sport Japan build). My solution is a little different- I grind down the tabs on the pads slightly so they slide more easily. Occasionally I have overdone it and the pads "clunk" a bit when brakes are applied, but performance is not affected.

 

Instead of grinding them down try using the file. You don't need to remove much material. There really is a balance where it'll run smoothly and no clunks.