Hyundai Forums banner
1 - 20 of 20 Posts

·
Registered
Joined
·
29 Posts
Discussion Starter · #1 ·
There are a few other discussions about this but I feel like I am missing something. I understand you can complete a pad change by removing the motor and twisting the piston until it opens. However, what do you do when you put it back to make it hold the rotor tight again? Do you just press the brake pedal a few times? Press the parking brake?

I hadn't changed brakes in about 10 years and I foolishly dove into changing these rear brakes. When I pulled the first caliper off I couldn't get the caliper to depress. I went into the car to put it into neutral and accidentally hit the EPB out of habit. It sent the piston on that wheel all the way out and set off the EPB light. I was able to locate a video on removing the motor etc and get the piston back in but there was some fluid bleeding out from around the seal. I cleaned it up, then tightened the piston as much as I could while still being able to slip it back over the new pads. Light turned off, parking brake works. Great.

Now I just can't shake the feeling that something is wrong. I can feel the brake pedal building some pressure when I press it a few times, and the car stops, but when I press the brake while in park I hear a "pish" (think of saying shhh with a p before it). Also, it builds pressure when pressing the pedal once or twice but then when I stop for a moment and press it again it's back to low pressure. I took the wheel off and there does not appear to be any more fluid leaking from the seal around the piston.


At this point I'm not sure if it always made this noise and I didn't notice and I'm just being paranoid, or if something is off...
 

·
Registered
Joined
·
257 Posts
Bleed your brakes, you may have air in the system.
Before you invest any more money, make sure you got good quality fresh brake fluid and no air.
Air compresses, brake fluid does not.
No leak is a good sign.

It's a two man operation, dont believe in any cheapo bleed check valve.
The ones that work cost too much for diy'er.
 

·
Registered
Joined
·
258 Posts
From what I’ve learned, after removing the motor, you can twist the piston to retract it and after your change the pads and put the motor back on, pump the brake pedal a few times until it pretty much becomes solid, start the car (this purges the fluid and gets the pump/booster working) and activate the EPB. Same exact process for a non-EPB pad change except that you have to remove the motor prior to retracting the piston and place it back afterward (shrug)

I definitely co-sign with @FuelSolGood, bleed your brakes and use high-quality fluid (suggestively Hyundai fluid but I’ve heard of guys using “top-tier” DOT3 and occasionally DOT4 fluid too) because while the servo does make a sound when the EPB is engaged, it certainly shouldn’t make a “pishhh” sound AFAIK.
 

·
Registered
Joined
·
29 Posts
Discussion Starter · #4 ·
Pulled the caliper off again today to check and it appears there is a pin hole in the gasket/seal around the piston. Obviously I pinched it at some point in the process.

That's probably why the brakes aren't staying pressurized. I called Hyundai to get a price on replacing the gasket and was told they aren't sure they can get just the gasket and may need a whole new caliper....
 

·
Registered
Joined
·
95 Posts
You should be able to source a brake caliper rebuild kit, which would come with that piston seal, along with new boots for the caliper slider pins. They're usually pretty cheap alternatives to replacing the entire caliper...
 

·
Registered
Joined
·
29 Posts
Discussion Starter · #8 ·
Thanks! I'm going to have to save that website.

I think I came across those and thought they would not work since they are fitted for the 2.4l when I have the 2.0T.

I've already had Hyundai ship in the caliper to do the work. I think the only reason the boot is leaking fluid is because the piston became unseated and let fluid into that area. It's not supposed to have fluid in there, it's just a dust boot right? If I was able to get a kit like that it would take days to get here, and then I would have to get someone to help me replace it and bleed the brakes. I can't take that time off of work, especially at this time of the year.

Lesson learned I guess...with a nice hit to the wallet.
 

·
Registered
Joined
·
258 Posts
Whoops! that’s my bad. Yeah the parts are the same for both the 2.4L and 2.0T as the part numbers are the same, they’re just listed under both sections! If you look to “2.0 L4 Turbocharged” and then “Brake & Wheel Hub”, you’ll see the same parts/items. :)
 

·
Registered
2007 Honda CRV
Joined
·
4,597 Posts
Unless you have great skill level in rebuilding calipers, better off just replacing the whole caliper.
It may cost less to rebuild a caliper. Replacing the caliper is so much quicker.
New calipers (and rebuilt) require bleeding the brakes
If the vehicle has ABS brakes then it may need a higher level scanner to bleed the brakes??

Strange .. rear disc brakes .. seems that some rear brake pistons may need to be turned while depressing back in
Especially if the caliper is used as part of the emergency parking brake system
 

·
Registered
Joined
·
258 Posts
Unless you have great skill level in rebuilding calipers, better off just replacing the whole caliper.
It may cost less to rebuild a caliper. Replacing the caliper is so much quicker.
New calipers (and rebuilt) require bleeding the brakes
If the vehicle has ABS brakes then it may need a higher level scanner to bleed the brakes??

Strange .. rear disc brakes .. seems that some rear brake pistons may need to be turned while depressing back in
Especially if the caliper is used as part of the emergency parking brake system

I agree that replacing the entire caliper is quicker, aside from needing to bleed the brakes lol.

Also as far as I know, almost all Asian cars that have disc brakes in the rear have a rotating rear caliper piston instead of a lateral one like in the front.
 

·
Registered
2007 Honda CRV
Joined
·
4,597 Posts
I agree that replacing the entire caliper is quicker, aside from needing to bleed the brakes lol.

Also as far as I know, almost all Asian cars that have disc brakes in the rear have a rotating rear caliper piston instead of a lateral one like in the front.
The thread starter mentioned there was a problem with depressing the piston back in.
Thought it would help to know that they need to be rotated while being depressed.
Also, if they have ABS brakes then should know that it can not be done just by conventional methods
Needs an upper level scanner to activate the abs unit to allow fluid flow
 

·
Registered
Joined
·
258 Posts
The thread starter mentioned there was a problem with depressing the piston back in.

Thought it would help to know that they need to be rotated while being depressed.

Absolutely and I personally appreciate sharing the knowledge! But OP also mentioned:

Pulled the caliper off again today to check and it appears there is a pin hole in the gasket/seal around the piston. Obviously I pinched it at some point in the process.

The troubleshooting is all done. Now the focus is helping OP resolve the issue, which - as it seems - will involve replacing the caliper itself instead of rebuilding it (replacing the damaged seals, etc.).
 

·
Registered
Joined
·
29 Posts
Discussion Starter · #14 ·
I certainly appreciate all the help - car is in the shop right now having the caliper replaced. I was especially nervous that the piston popping out could have compromised the caliper.

Definitely didn't twist the pistons when retracting them. I dont see how that would be possible as they are notched to fit over a piece sticking out of the brake pad and remain stationary.

Here's to hoping I didn't mess anything else up...
 

·
Registered
Joined
·
1,340 Posts
Normally, when a caliper has a piston that needs to be spun to retract it into the body, the face of the piston will be notched or slotted to accept the tool that will spin the piston back into the caliper body.
I have not seen a piston that did not have some sort of notches or slots that required being spun to be pressed back into the caliper body.
Not that there may be one out there somewhere, but a sure sign that the piston needs to be spun is the slots or notches.
I have also seen pistons with slots or notches that did not need to be spun but I have never seen the opposite.


Good luck with the repair.
 

·
Registered
Joined
·
95 Posts
I have a 2010 Passat with a electronic parking brake on the rear calipers. It's been awhile, but I'm pretty sure there was no notch or groove in that piston, but it did screw in using the motor mounted to the caliper. There isn't an option to do it manually on that car, so I hooked the pins from the motor switch to a 12V battery and operated the motor myself in order to do the brakes for a fraction of the cost the dealer quoted.

You gotta be careful going this route though, if you rotate the piston too far out then you destroy a very expensive caliper!
 

·
Registered
2016 Sonata Limited 2.4 GDI
Joined
·
31 Posts
EPB with scan tool

I have a 2010 Passat with a electronic parking brake on the rear calipers. It's been awhile, but I'm pretty sure there was no notch or groove in that piston, but it did screw in using the motor mounted to the caliper. There isn't an option to do it manually on that car, so I hooked the pins from the motor switch to a 12V battery and operated the motor myself in order to do the brakes for a fraction of the cost the dealer quoted.

You gotta be careful going this route though, if you rotate the piston too far out then you destroy a very expensive caliper!
I think with this type of EPB you need to use a scan tool to retract and reset the caliper and brake pad just as described in the Kia procedure.
 

·
Registered
Joined
·
95 Posts
It's doable without the scan tool, at least on the Passat. I'm going on 25,000 kms since I did that with no issues. Dealer quoted me $500 for rear pads and rotors, partly due to the fancy scan tool they needed to use.

I did it for $125 in my driveway in an hour, plus an extra $20 for the 8-pack that I treated myself to afterwards :)
 

·
Registered
Joined
·
1,340 Posts
I don't like when the parking brake is incorporated into the caliper.
The parking brake should be a smaller drum with shoes in the center of the rear rotor.
Much cleaner and less likely for something to go wrong with the entire system.
 
1 - 20 of 20 Posts
Top