JAB

Hi: Trying to replace rear brake pads. Can't get the caliper piston to retract far enough to permit reinstallation over the new pads. Have opened the bleed screw. I believe I have the parking brakes off - red light off, correct? Please Help!!

Lexuswiz

iTrader: (1)

During rear brake pad replacement you need to put the electronic E-brake into a sort of service mode. Stupid but I went through it. I used techstream to release the electronic E-brake, but here's a way to do it without. Give this guy a like and follow, he's here on this forum and his videos are CLUTCH.

JAB

What is the key to whether my DOC3 is upside down or not? Is it simply the rounded edges? If the rounded part is 'up' does that mean that my terminals 4 & 12 are measured from the left, and if the rounded part is 'down' then terminals 4 & 12 are measured from the right?

Lexuswiz

iTrader: (1)

So the true top of the OBD2 port is typically towards the widest part, with PIN 1 being top leftmost like the paper diagram in the video. I recall the OBD2 port on the NX is upside down if you look directly at it.

JAB

So 4 & 12 are 4th from the right?

n0v8or

My connector is oriented this way when viewed from the drivers position. Some wire colors may be different in pre-2017 models.

LexMan2003

If you believe the brake is OFF, and you're just short a little bit of room, and cannot get the NEW pad(s) on, then what you could do is:

1 - take the cover/cap off of the brake fluid reservoir in the engine compartment
2 - place the cap on top of the reservoir so that it will allow some of the air to come out of there, but protect against any dirt dropping in
3 - go back to that caliper and take the pads off
4 - uncompress the caliper so that the caliper is fully retracted, which should give you the room you need to install the NEW pad(s)
5 - go back to the reservoir and re-install the cap completely

JAB

LexMan: Does your method work without electrically contracting the parking brake servo?

LexMan2003

I was simply responding to the OP trouble with "can't get the caliper piston to retract far enough".

I understand there are some steps to take to 'disable' the electronic parking brake, but I assumed he was already aware of this and took those steps already and STILL couldn't get enough retraction !

JAB

Is it possible that once the rear brake pads become too worn down that the electronic parking brake becomes 'unavailable' and generates 'malfunction' and 'see your dealer' messages?

chas410

Did you complete your rear brake change? Just wondering if you learned anything that may help when I try to do it.

Lexuswiz

iTrader: (1)

I have done a 2015 NX200t F Sport AWD prior to my own but finally did mine using all OEM parts this weekend. Compared to the last one I did, OEM Lexus pads includes new bolts for the caliper that comes pre-thread-locked, I like this and recommend OEM. The aftermarket Akebono's on the last NX I did not come with any but had new shims which OEM sells separately (you can re-use old ones if they're in good shape). Also the slide pin bolts love to spin, be aware of that before you twist and rip the boot.

I will say, having a OBD2 tool that can put the electronic ebrake into service mode is far more convenient than manually releasing the electronic portion of the brake.

Shermang

Doesn't seem like a solution was reached so I'll throw in my 2 cents. When I did my rear brake change, I disabled the parking brake inside, piston still wouldn't depress with C-clamp, so there is a 6 point star torx connection behind the caliper that you can loosen to depress the piston and fit in the brake pads. Once done and brake pads are in, tighten back to the original tightness or as close as possible. Since it's an electronic brake, I don't know how essential it is for it to be the same exact torque specification, but I tried to get as close as possible to avoid messing anything up. Hope this helps.

chuyrobles

Victor Automotive seems to have a good video on placing the rear brake in service mode. It retracts the piston fully so you can replace the pads. I replaced the pads on my sister's NX before this video came out and I did the method shown in bottom video, where you manually retract the piston.

Roscol

Using the Victor YouTube video and placing the rear brakes into service mode to fully retract the piston is the only way to go.

A simple paperclip and watching the video will make quick work of replacing your pads and/or rotors on the rear with not much fuss.

Just remember to re-connect the piston electrical connection when completing the work or you’ll get a bunch of error messages, lol.