[Kimble1986]

I have a 2019 Pacifica sport and when I started to retract the brakes in the LCD screen the caliper wouldn’t retract. The screen told me the caliper was retracted and that was not the case. The screen also mentioned to get out of service mode, press the brake and push the parking brake. So I did so and my entire caliper piston shot out with brake fluid everywhere. I’m not a certified mechanic by any means. I Do however learn fast and need some serious help. This is my family’s only means of transport. Is my caliper done? Do I need a new one? I’ll try and post a picture with this.

 

[PacDave]

I have a 2019 Pacifica sport and when I started to retract the brakes in the LCD screen the caliper wouldn’t retract. The screen told me the caliper was retracted and that was not the case. The screen also mentioned to get out of service mode, press the brake and push the parking brake. So I did so and my entire caliper piston shot out with brake fluid everywhere. I’m not a certified mechanic by any means. I Do however learn fast and need some serious help. This is my family’s only means of transport. Is my caliper done? Do I need a new one? I’ll try and post a picture with this. View attachment 50898

You will likely need a piston rebuild kit if there is one. You should replace the piston seal and the dust boot. There may be no damage and you could just carefully reassemble it as is but as cheap as these are, you might as well just replace them. You should never apply brakes with no pads/rotor in place unless your intent is to extract the piston (which you’ve done).

And by the way, there normally is no way to retract a brake piston without mechanical persuasion. That would require negative hydraulic pressure (suction). What you have done is to extend the piston beyond its normal operating limits because you disassembled the caliper and left the pads behind. When you applied the brakes there was nothing to keep the piston from simply pushing out of the caliper.

 

[PacDave]

Another thing to keep in mind. The brakes on your car are “life safety” items. In other words, if they don’t operate correctly it could kill you. There is nothing wrong with working on brakes yourself if you know what you’re doing. Don’t simply experiment or say to yourself, “I think this is the way it’s supposed to be”. Lives are at stake. Make sure you know the job and you do it right. Ask someone who’s done a brake job before to look over your shoulder.

 

[PacDave]

And just another thought: the retraction of a brake cylinder is normally done to make room for new brake pads that are being installed. If there is some option in a service menu for retracting them I can only assume that it simply releases some sort of check valve somewhere and allows you to then manually retract the piston. I usually do this with a large screwdriver as a lever to put pressure against the piston and make it retract back inside the caliper. Most cars allow you to do this without any special preparations.

 

[Kimble1986]

You will likely need a piston rebuild kit if there is one. You should replace the piston seal and the dust boot. There may be no damage and you could just carefully reassemble it as is but as cheap as these are, you might as well just replace them. You should never apply brakes with no pads/rotor in place unless your intent is to extract the piston (which you’ve done).

And by the way, there normally is no way to retract a brake piston without mechanical persuasion. That would require negative hydraulic pressure (suction). What you have done is to extend the piston beyond its normal operating limits because you disassembled the caliper and left the pads behind. When you applied the brakes there was nothing to keep the piston from simply pushing out of the caliper.

Lesson learned! I thank you kindly for your wisdom. I see where I made my mistake and will go ahead and buy a new caliper. I wasn’t used to the retractable spinning piston. I’ve always have changed pads on my vehicles. These new ones have a lot more to them. Thanks again and thanks for this forum. 😎

 

[Kimble1986]

Lesson learned! I thank you kindly for your wisdom. I see where I made my mistake and will go ahead and buy a new caliper. I wasn’t used to the retractable spinning piston. I’ve always have changed pads on my vehicles. These new ones have a lot more to them. Thanks again and thanks for this forum. 😎

P.s is the actuator still useable?

 

[CANADAHYBRIDGUY]

There are tools that allow you retract the pistons after you’ve removed them from the rotor . Just also keep this in mind , brakes are t that hard to do these days just keep in mind the torque settings for the caliber bolts , brake clips if so required or the brake adhesive . And also be careful of the caliper seal as that’s the make or break of buying a new one . When I’m doubt let a certified tech do it , somebody with brake knowledge . Good luck

 

[freddief73]

Service mode retracts the parking brake actuators so that the rear brakes can be serviced. It doesn't do anything with regard to the hydraulic part of the brake system. You should be able to carefully reassemble the caliper without replacing any parts provided there's no visual damage. You will need to bleed the brake fluid after everything is reassembled. It's also important to note that the rear caliper pistons need to be twisted as they are compressed.

 

[thclimer]

It's also important to note that the rear caliper pistons need to be twisted as they are compressed.

On our 2019 I thought you had to twist the rear caliper as well and almost purchased a tool to do so as I had seen some YouTube video's showing this. However, once I had disassembled it there were no holes for the tool to twist the caliper piston and to my surprise it was pretty easy to compress as compared to some front calipers where I have used a large C-clamp.

Maybe the twisting is required on 2020 and newer Pacifica's?

 

[PacDave]

On our 2019 I thought you had to twist the rear caliper as well and almost purchased a tool to do so as I had seen some YouTube video's showing this. However, once I had disassembled it there were no holes for the tool to twist the caliper piston and to my surprise it was pretty easy to compress as compared to some front calipers where I have used a large C-clamp.

Maybe the twisting is required on 2020 and newer Pacifica's?

You should be able to tell if the piston needs to be twisted in by looking for notches on the part of the cylinder that makes contact with the pad. If there are notches on the piston then it will likely need to be twisted when it’s retracted so that it can engage correctly with the parking brake mechanism.

 

[Cpowell24]

Service mode retracts the parking brake actuators so that the rear brakes can be serviced. It doesn't do anything with regard to the hydraulic part of the brake system. You should be able to carefully reassemble the caliper without replacing any parts provided there's no visual damage. You will need to bleed the brake fluid after everything is reassembled. It's also important to note that the rear caliper pistons need to be twisted as they are compressed.

I have a question. I believe my actuator may be having problems. but im not sure what exactly. I put my Ebrake on the other day and it wouldn't release the driver rear side. so stupidly i tried to turn the put the Ebrake in service mode hoping that would retract the piston. it did not. I had to unscrew the back of the caliper (the motor i believe? or actuator?) off for the caliper to let go of the rotor. could this be a problem with the motor on the back not sensing the pressure? or could i have to take a screw driver to the part i had to pull off of the caliper to make it think that the parking brake is in service mode?

 

[BennyRT]

You will likely need a piston rebuild kit if there is one. You should replace the piston seal and the dust boot. There may be no damage and you could just carefully reassemble it as is but as cheap as these are, you might as well just replace them. You should never apply brakes with no pads/rotor in place unless your intent is to extract the piston (which you’ve done).

And by the way, there normally is no way to retract a brake piston without mechanical persuasion. That would require negative hydraulic pressure (suction). What you have done is to extend the piston beyond its normal operating limits because you disassembled the caliper and left the pads behind. When you applied the brakes there was nothing to keep the piston from simply pushing out of the caliper.

My friend recently acquired this 2019 Pacifica. He tried to retract the brake and it didn't retract. It seems it also needs a piston rebuild. We'll just finish installing the brake pads and gear wheels on the truck tomorrow and we'll work on it.