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Old 11-11-2017, 04:21 PM   #1
DGMSTI
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Member#: 435906
Join Date: Dec 2015
Chapter/Region: W. Canada
Location: Alberta
Vehicle:
2015 WRX STI
DGM

Default Bleeding brakes, non-stop bubbles

Intro
I drive a 2015 STI, I took my calipers off to paint them with G2 caliper paint. When reinstalling I bled my brakes, minimal brake pressure. Bled again, minimal pressure. Bled it a third time with a buddy, spent 3 hours making sure I was not making any mistakes, still only minimal pressure. Each time, every single caliper's line was constantly emitting a stream of tiny, tiny bubbles and sometimes bigger bubbles. Half an hour of bleeding either of the rear calipers or the front left the bubbles would be almost gone. An hour of bleeding the front right and no signs of bubbles slowing down. The front right also would start bleeding with huge air bubbles for a while.
This was my first time bleeding brakes, so I figured I must have made a mistake the first two times. My inexperience led me to believe these tiny bubbles must be normal as they just won't go away. I am sure I did it properly the third time. Master Cylinder never dipped below halfway. I always did brakes in order PR, DR, PF, DF.

Possible reasons for the issues
  1. I got into an accident recently where I damaged multiple suspension pieces. Front right control arm, both rear trailing links. This is the first time starting the car since. Maybe part of my brakes were damaged?
  2. When I took the brakes off to paint, I split the front right caliper before realizing I am not supposed to. I cleaned the surface then put it back together using loctite on the threads. I am betting this is the issue because it is the caliper with the worst air.
  3. When attaching the brake lines into the caliper I did not have new copper washers. I have ordered these and will replace.
  4. While painting, I got a bit of paint on the caliper piston boot.

What I have tried
I tested my brakes at speeds up to 40km/h. Brakes would start to work near the floor, but minimally. Parking brake works perfectly fine to slow me down telling me my rear brake lines are fine.
I have pressure when I pump the brakes with the car off. I lose pressure if I turn the car on. However after the 3rd bleed, if I pump the brake with the car on I will gain pressure, but if I move even 1 inch the pressure will disappear.

Questions
What do you think is the problem
Is there a way for a brake shop to pressurize my lines to see where in my brake system or which caliper is having issues?
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Last edited by DGMSTI; 11-11-2017 at 04:30 PM.
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Old 11-11-2017, 05:49 PM   #2
Charlie-III
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Member#: 30669
Join Date: Dec 2002
Chapter/Region: Tri-State
Location: USA, North NJ, 07456
Vehicle:
1998 Legacy 2.5GT
Silver Sleeper BK, 5MT

Default

You likely have ABS, may be air in the ABS pump.

E-brake on 4 wheel disc is a separate circuit, ignore that. Driving brakes are pads, E-brake is a cable to shoes in a drum within the rear rotors.....totally separate. No relation......

Again, ignore the E-brake in this issue.

Oh, did I mention to ignore the E-brake in this case?!

Ignore the E-brake.......in case you missed it.........

So......you can reuse (here come the flames to me........) the copper washers for the banjo bolts to the calipers.
I carefully flat file them down (if in a pinch, new is much better) on both sides, then torque up the banjo bolt.

If you don't have brake fluid leaks anywhere, you have air in the system.

If you have leaks, then fix them, then rebleed.

To help bleed the ABS pump, bleed the brakes, then go find dirt or gravel, run up the car speed and romp on the brakes to invoke the ABS.
Then go back and bleed the brakes.

In general.......
Fix leaks first.
Fix leaks first (not a miss post, just checking.....)
Keep the master cylinder reservoir topped off.
Bleed each wheel.
Don't forget to compress the piston (with the bleeder open) to push out crud in the bottom of the caliper bore.

Let us know what you find.
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Old 11-11-2017, 05:55 PM   #3
Charlie-III
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Location: USA, North NJ, 07456
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1998 Legacy 2.5GT
Silver Sleeper BK, 5MT

Default

Sorry if I seem to be repeating myself, just really highlighting what are the main concerns here.....
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Old 11-11-2017, 05:58 PM   #4
DGMSTI
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Join Date: Dec 2015
Chapter/Region: W. Canada
Location: Alberta
Vehicle:
2015 WRX STI
DGM

Default

Quote:
Originally Posted by Charlie-III View Post
You likely have ABS, may be air in the ABS pump.

E-brake on 4 wheel disc is a separate circuit, ignore that. Driving brakes are pads, E-brake is a cable to shoes in a drum within the rear rotors.....totally separate. No relation......

Again, ignore the E-brake in this issue.

Oh, did I mention to ignore the E-brake in this case?!

Ignore the E-brake.......in case you missed it.........

So......you can reuse (here come the flames to me........) the copper washers for the banjo bolts to the calipers.
I carefully flat file them down (if in a pinch, new is much better) on both sides, then torque up the banjo bolt.

If you don't have brake fluid leaks anywhere, you have air in the system.

If you have leaks, then fix them, then rebleed.

To help bleed the ABS pump, bleed the brakes, then go find dirt or gravel, run up the car speed and romp on the brakes to invoke the ABS.
Then go back and bleed the brakes.

In general.......
Fix leaks first.
Fix leaks first (not a miss post, just checking.....)
Keep the master cylinder reservoir topped off.
Bleed each wheel.
Don't forget to compress the piston (with the bleeder open) to push out crud in the bottom of the caliper bore.

Let us know what you find.
Didn't know about the parking brake. I know in automatic cars you are supposed to engage your parking brake every once in a while to keep your rear calipers from seizing and that in a manual car, we pull the parking brake every time we park so we don't worry about it. Is it different for manual and automatics or is this just wrong then?

So how would I check for leaks? When bleeding each caliper I checked underneath the car multiple times for any fluid leaks and found nothing. Does this mean I am good?
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Old 11-11-2017, 06:20 PM   #5
Charlie-III
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1998 Legacy 2.5GT
Silver Sleeper BK, 5MT

Default

In "most" 4 wheel disc brake systems, the E-brake is shoes inside the rear rotors. Some have a mechanical linkage to the caliper for the brake.

"In general" the E-brake and foot brake are different systems......so, in general, ignore the 2 systems and their operation.


So, we get back to a "spongy pedal" which sounds like air in the system.

ABS can complicate this by holding air in the pump.

Great is having a scanner that can cycle the ABS pump, crude is to bleed brakes, find a loose surface, invoke ABS, re bleed the brakes.
Work with what you have.

What more can I say unless you come to my house?
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Old 11-11-2017, 06:23 PM   #6
Vancouver98STi
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1998 JDM Impreza STi
White GF8 wagon

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Quote:
Originally Posted by Charlie-III View Post

So......you can reuse (here come the flames to me........) the copper washers for the banjo bolts to the calipers.
I carefully flat file them down (if in a pinch, new is much better) on both sides, then torque up the banjo bolt.
No flames... except for the one from the torch that should be used to anneal reused copper washers.



No, that's not me in the video.

Instead of using forceps to anneal each washer individually, I insert a length of stripped solid copper wire (or a thin steel rod) through all the washers I wish to process and do the whole works of them at once.

Last edited by Vancouver98STi; 11-11-2017 at 06:32 PM.
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Old 11-11-2017, 06:25 PM   #7
Charlie-III
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Join Date: Dec 2002
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Location: USA, North NJ, 07456
Vehicle:
1998 Legacy 2.5GT
Silver Sleeper BK, 5MT

Default

You are at least a few thousand miles from me, not worth the trip.
Better to either follow my suggestions or find somebody local that has a minor clue on brakes.
Really, this does not seem too hard......."if" you have a clue on how brakes work.


Really........
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Old 11-11-2017, 06:35 PM   #8
DGMSTI
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Location: Alberta
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2015 WRX STI
DGM

Default

I was mostly worried that splitting the caliper was the reason for my problem as it is the caliper which always has the most air coming out of it.
What I am getting is that if there was a problem with the caliper, I would see a fluid leak? So the problem I have is there must just be air stuck somewhere, likely in the ABS?

One more question. I noticed on my calipers there are 2 bleed valves, one on each side. I have been using the outside side, is there a difference?
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Old 11-11-2017, 07:16 PM   #9
Plecain
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You have to do both. Inside first.
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Old 11-11-2017, 09:29 PM   #10
08OBS
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Default

You may be opening the bleeders too much. When I first learned how to bleed brakes I would open the bleeder a lot so more fluid would come out. There was always air bubbles and then I learned that air was coming in past the threads of the bleeder. Now I just open them a little to let a small amount of fluid out and wait until there are no bubbles.

Now I use the Motive Power bleeder and I go around all four corners twice, then I start the car with the bleeder still attached, pump the brakes and then shut the car off. I do the final bleed on all the calipers and I am good. Nice solid brake pedal. Hope this helps. Good luck!
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Old 11-12-2017, 03:54 AM   #11
MedicDG
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Quote:
Originally Posted by Plecain View Post
You have to do both. Inside first.


What he said!
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Old 11-12-2017, 04:02 AM   #12
MedicDG
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WRB

Default

Quote:
Originally Posted by DGMSTI View Post
Intro
I drive a 2015 STI, I took my calipers off to paint them with G2 caliper paint. When reinstalling I bled my brakes, minimal brake pressure. Bled again, minimal pressure. Bled it a third time with a buddy, spent 3 hours making sure I was not making any mistakes, still only minimal pressure. Each time, every single caliper's line was constantly emitting a stream of tiny, tiny bubbles and sometimes bigger bubbles. Half an hour of bleeding either of the rear calipers or the front left the bubbles would be almost gone. An hour of bleeding the front right and no signs of bubbles slowing down. The front right also would start bleeding with huge air bubbles for a while.
This was my first time bleeding brakes, so I figured I must have made a mistake the first two times. My inexperience led me to believe these tiny bubbles must be normal as they just won't go away. I am sure I did it properly the third time. Master Cylinder never dipped below halfway. I always did brakes in order PR, DR, PF, DF.

Possible reasons for the issues
  1. I got into an accident recently where I damaged multiple suspension pieces. Front right control arm, both rear trailing links. This is the first time starting the car since. Maybe part of my brakes were damaged?
  2. When I took the brakes off to paint, I split the front right caliper before realizing I am not supposed to. I cleaned the surface then put it back together using loctite on the threads. I am betting this is the issue because it is the caliper with the worst air.
  3. When attaching the brake lines into the caliper I did not have new copper washers. I have ordered these and will replace.
  4. While painting, I got a bit of paint on the caliper piston boot.

What I have tried
I tested my brakes at speeds up to 40km/h. Brakes would start to work near the floor, but minimally. Parking brake works perfectly fine to slow me down telling me my rear brake lines are fine.
I have pressure when I pump the brakes with the car off. I lose pressure if I turn the car on. However after the 3rd bleed, if I pump the brake with the car on I will gain pressure, but if I move even 1 inch the pressure will disappear.

Questions
What do you think is the problem
Is there a way for a brake shop to pressurize my lines to see where in my brake system or which caliper is having issues?


First like what has been said. You must bleed inside first then outside. If you don't do it in that order you will have air in your lines.

What you described sounds like there is air in your lines. I would rebleed calipers you painted again starting with inside bleeder first. I also recommend using a Motive pressure bleeder and a harbor freight bleeder kit to suck out brake fluid. I have used this method for many year with zero problems.
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Old 11-12-2017, 11:10 PM   #13
Doxparadise
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GBP

Default

Did you put the calipers on the wrong sides? I.e. are they upside down with the bleeders facing down instead of up? If so that's the problem because you can't get all the air floating to the top of the caliper.
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Old 11-12-2017, 11:42 PM   #14
DGMSTI
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Member#: 435906
Join Date: Dec 2015
Chapter/Region: W. Canada
Location: Alberta
Vehicle:
2015 WRX STI
DGM

Default

So I did it again but did the inside lines first and only opened the valves a tiny bit and it fixed the problem. Actually saw no air bubbles. All the instructional videos I saw showed brakes with only one bleeder valve per caliper and I didnt know to do both. Still a little soft so I will rebleed after Ive driven it a bit and activated ABS a few times

Thanks for the tip Plecain
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