Rear Brake Piston Will not retract - any suggestions?

[rldhs]

Today I was changing the brake pads on 2018 RTL (60k mi). Front replaced without issues

I have changed brake pads twice before without problems.

I cannot get the rear brake piston to retract. It rotates but does not retract. I did press pedal and it extracts without a problem so the piston does move. I have used brake piston tool sold by Lamonster and BajaRon and also tried needle nose pliers. I am pushing in to apply pressure as I turn the piston clockwise. I searched the forum and saw a similar issue from 2020, but thought I would ask if information for an update.

I have been at this for hours and decided to call in a night.

Any suggestions from the group on how to get the piston to retract? Or is it just time to get a new caliper?20220820_214403.jpg

[trikermutha]

I think you over extended the piston. Trick now is to get it to seat back into the thread while you turn it. Apply pressure while turning it until you can get the threads to catch again. Take your time

I just don’t remember with direction to turn but want to say counterclockwise.

[Mikey]

You got to push harder, while turning, hate to say it you may have to take it off and put it in a vice so you can get your weight into it. Good luck sometimes there a PITA!

[FlyBoy2121]

I Guys, yes remove the disconnect the Oil pipe but in a vice and you push the piston but by turning it a little, but not too much you will take the piston out of the seal, I did that but I wondered make a tool to do the job.
FlyBoy2121

IMG_007.jpg

[rldhs]

Thank you.

I have been applying pressure but trying to find a way to apply more and turn at the same time.

The youtube videos I have seen show turning in a clockwise direction to retract the piston.

[rldhs]

Yes I thought about disconnecting and putting in a vice. Just a pain since that then require brake flush or bleed. But as you said I may have no other option.

I have been thinking about taking a C- Clamp and welding the BajaRon Retractor to the end of the clamp. I think this would allow much more pressure and also allow me to rotate the piston as the clamp closes. Since it is Sunday, I will have to wait until tomorrow when a welding shop is open to try this test but I think it could work. If I end up trying this option I will post back the results.

Thank you for responding.

[rldhs]

Yes I thought of the same and may end up having to do just as you suggest.

Thank you for your suggestion.

[BLUEKNIGHT911]

Thank you.

I have been applying pressure but trying to find a way to apply more and turn at the same time.

The youtube videos I have seen show turning in a clockwise direction to retract the piston.

The currant " Brembo " brake system ( according to this forum ) is a " screw in to retract " ..... forcing it in will cause damage and require a new caliper assembly ..... good luck .... It's possible that when you applied pressure after it was OFF the rotor you need to RESTART threading it ...... Mike

[K80Shooter]

Maybe use a C clamp or any type of clamp to apply pressure just a little bit while turning.

[BertRemington]

I had same situation with rear brake caliper. Gave up after trying BR tool in bench vise and bought a used caliper on eBay. BR tool quickly retracted piston allowing me to install EBC pads.

The old rear pads were worn almost to the base plate while the front pads were about 50% so I think the previous owner had tried to retract the piston, damaged the threads and gave up on new pads.

I've read where some people said they rotated the parking brake lever in the reverse direction but mine didn't allow that.

[Peter Aawen]

I had same situation with rear brake caliper. Gave up after trying BR tool in bench vise and bought a used caliper on eBay. BR tool quickly retracted piston allowing me to install EBC pads.

The old rear pads were worn almost to the base plate while the front pads were about 50% so I think the previous owner had tried to retract the piston, damaged the threads and gave up on new pads.

I've read where some people said they rotated the parking brake lever in the reverse direction but mine didn't allow that.

That's what you needed to do on the earlier version of Spyder Brakes, but not on the Brembos that've been in use since 2013!

[FlyBoy2121]

I Guys !!
Go to this address you will see how the inside of the caliper is made, it is not that of the Spyder but it is identical, because I have a caliper that comes from a spyder of a friend of mine, and it is identical to that of this address, it is complex.

https://wiki.seloc.org/a/How_to_Rebu...Brembo_Caliper

FlyBoy2121

[Isopedella]

Thats awesome. Thanks Flyboy2121.

[BajaRon]

A more common problem than would be expected. Once the piston detaches from the threads, it's a bear to get it to re-engage. As you have discovered. You have to apply a good deal of pressure to collapse the very strong spring behind the piston. Unfortunately, this is difficult to do with the caliper attached to the brake line. The threads are fine so the piston needs to be perfectly mated, flush with the threads to avoid cross threading them.

It seems that the adjustment has little if any reserve run-out. So that when the pads are worn too much, the piston disengages on its own.

As discussed, you may need to remove the caliper to give you the ability to apply the needed pressure. If you do. Raise it up so that you drain as little as possible from the system. This will make bleeding easier.

Good luck.

[UtahPete]

Great thread for gear-heads. Thanks.