Toyota electric parking brake screwup--help!

[supton]

I think I blew it...

So I followed the procedure to unlock the parking brake, so I could lube sliding surfaces. Took apart and found I need new pads. Got a set. Went to put in, and... can't push the piston in. Google it. Ok, have to start the car, pull up on the parking brake 3 times, push down 3 times, then hold down, and it's supposed to pull the piston all the way.

It decided to push all the way out...

and one piston is now out.

One side has a board firmly clamped and won't let go, the other side, well I think it's screwed as the board fell out and so did the piston. New caliper time on both sides? time to have it towed? what do I do now?

Why is this so complicated??? I just wanted to lube the frickin pad ears, only to have now bricked the car.

 

[Chris142]

Was the caliper unbolted when you pushed on the pedal?

 

[supton]

Was the caliper unbolted when you pushed on the pedal?

Calipers were out, but I never touched the pedal. Was trying to use the "service brake" after getting pads in, as I did not realize that this car has a fancy procedure to wind the pistons back in. Somehow I must have screwed up the procedure, and told it to push the pistons out, and one side didn't have something to stop the piston from overtravel.

Edit: video link.

 

[Slick3914]

I think you were to do that with the caliper still attached.

 

[supton]

I think you were to do that with the caliper still attached.

Yeah I got that message now... I was *not* planning to do brakes when I started. Apparently the right way to do this is, always wind it all the way back in, that way if you wind up doing brakes, then you're all set. Otherwise you're potentially screwed...

 

[spackard]

I’d go through the procedure to retract them again, to get the motors to think/move to full retraction.
Next, get the pistons back in the bores and bleed the air.
Third, get the stuff back onto the car.
Fourth, return parking brake system to normal.
Then retract again, and then do the job you originally wanted to do.
Bleed air again.

 

[Warstud]

Just loosen the bleeder screw as you turn the piston . If you look inside the caliper you'll see that it looks like a bolt and the piston screws onto it like a nut .

 

[mk378]

You just needed to slap it back together with the old pads. In situations where the piston is retracted without rotating it, I like to clamp or pry on the old pads to push the piston back before removing the caliper.

 

[supton]

Got it to go into service mode, and on the "good" side I was able to push the piston in by the usual caliper tool (no winding required). EXCEPT it's 1mm not enough. Won't fit over the Carquest pads. Piston does not look like it wants to go the last bit in. Don't expect a 2 yr old caliper to have issues, but who knows. Reluctant to give it all I've got, I guess I could take out an old old pad that is half worn and use that.

On the bad side, the piston spins but I don't feel any threads for it to engage into? Feels like something there, but spinning in either direction doesn't yield the end of a thread. Will crack the bleeder and see if that helps.

Sounds like I need to give in and order a set of rotors, pads and calipers. And a computer so I can get Techstream (don't have a laptop to use in the garage), as I am not sure if I need that to bleed brakes or whatever. But it sounds like I need to give in and get one.

Last time I screwed up a brake job... well I wrecked the car, so it's not that bad yet. Still not happy though.

 

[supton]

After spinning the popped piston a bunch of times... it went in? odd. On the other side, the one that wouldn't push in far enough... I elected to try spinning that piston too. Shock of shocks, in it went. All bolted together.

Time to toss on the wheels and see if it goes and stops I guess.

 

[MSCH]

After spinning the popped piston a bunch of times... it went in? odd. On the other side, the one that wouldn't push in far enough... I elected to try spinning that piston too. Shock of shocks, in it went. All bolted together.

Time to toss on the wheels and see if it goes and stops I guess.

question... I have no specific knowledge of what Toyota is doing, but if you unplugged the wiring to that electric parking brake, should you not be able to retract the part in question?

 

[Dan55]

This will give you some insight into how it works! https://www.clublexus.com/forums/at...acement-nx_rear_brake_service_qtg_outline.pdf

 

[supton]

question... I have no specific knowledge of what Toyota is doing, but if you unplugged the wiring to that electric parking brake, should you not be able to retract the part in question?

I’ve seen posts about applying 9V to the motor, to spin in or out. Didn’t want to try try that just yet.

Survived a quick 5 mile jaunt, up to 60, no hot brakes, no brake issues. Will monitor and go from here.

 

[Slick3914]

Might be time to call a tow truck

 

[Dan55]

When you park the car can you hear the parking motors engage?

 

[supton]

When you park the car can you hear the parking motors engage?

I don't--yet I think they are working. Will check more closely tomorrow.

 

[atikovi]

And a computer so I can get Techstream (don't have a laptop to use in the garage),

Why not print out the relevant pages.

 

[supton]

Why not print out the relevant pages.

That's no help if I need it to tell the ECU to cycle the ABS pump or to read codes or whatever. Bound to toss a code someday.

 

[atikovi]

That's no help if I need it to tell the ECU to cycle the ABS pump or to read codes or whatever. Bound to toss a code someday.

You mean you have the $1500 Techstream interface but don't have a laptop to use it?

 

[supton]

You mean you have the $1500 Techstream interface but don't have a laptop to use it?

Have neither. I've been winging it for years with just a Scangauge to read codes, sometimes Torq. Use to have a cheapo Techstream on an old Win7 laptop but might be time to step up in life.