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Discussion Starter #1
While replacing my brake pads on my 1999 Legacy Wagon w/ ABS I decided to bleed the brakes using the 2 person pedal pumping method. In the process I broke the caliper guide pins on one set, so I replaced those and carried on with the bleed. All I got was super spongy brakes (all the way down), so after bleeding the heck out of all the wheels maybe 5 times without getting any brakes, I replaced the Master Cylinder. Always keeping the MC full of brake fluid.

Bench bleed the new one (getting the correct MC was difficult- for some reason most 1999s don't have ABS with the 2 fluid lines coming out the side rather than one on top), installed it and bleed the brakes using the same method, but still - no brakes. Thinking there was still air in the system, I bleed them over a few days, driving around the block and engaging the ABS, parking it downhill with the rear end up...bleeding and bleeding with no avail.

Mobile mechanic came by today to bleed them with different method -1 person, push pedal to ground and then let up suddenly. Didn't work. Bench bled the old one -just to see-, installed it, still no brakes.

Mechanic thought that I broke both MCs by pushing too hard to the ground to bleed the brakes.

I'm thinking, what are the odds? But what else could it be?:confused:
 

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I've always been a fan of putting a 4" scrap of 2x4 on the floor under the brake pedal to prevent hyperextension during a bleed, but I've only seen one MC ruined because we didn't do that- and it wasn't a subie.

Any chance you damaged a seal on a caliper through all this?

Any chance a bleeder isn't really closing, or has developed a crack?

You didn't mention removing calipers, but just in case you did: did you put them back on the same sides they came off of?
 

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^What Rasterman said. In other words, are the bleeder screws at the top of the calipers?

If you had good pedal feel and reaction prior to replacing the pads, the old MC is good. There is something not tightened or if you removed the calipers all to together and remounted them on the wrong wheel, the air is in the caliper because it can't get out.

How did you break a guide pin? Over torqued? Rusted in the bracket? Just curious.

Mobile mechanic? I also doubt the MC was damaged through bleeding/flushing. The pistons in the MC will only travel so far before they stop.
 

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You have air in the system. Try reverse bleed. Get a squirt bottle with a fine tip. Fill up with fluid. Turn upside down, purge and open the bleeder port. Slowly squeeze and fill while a buddy helps remove excess fluid from the reservoir with a syringe. This works better for me since air travels up. I had a motorcycle and this was the only way to get all the air out.
 

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Discussion Starter #5
I've always been a fan of putting a 4" scrap of 2x4 on the floor under the brake pedal to prevent hyperextension during a bleed, but I've only seen one MC ruined because we didn't do that- and it wasn't a subie.

Any chance you damaged a seal on a caliper through all this?

Any chance a bleeder isn't really closing, or has developed a crack?

You didn't mention removing calipers, but just in case you did: did you put them back on the same sides they came off of?
I didn't take the calipers completely off, just enough to slide the pads in, so they stayed on the same side.

I get a little air just about every time I bleed the brakes. I was wondering if the bleeder might have a tiny leak, especially since I used vise-grip :29: instead of the correct wrench.

But wouldn't I see a leak??
 

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Discussion Starter #6
^What Rasterman said. In other words, are the bleeder screws at the top of the calipers?

If you had good pedal feel and reaction prior to replacing the pads, the old MC is good. There is something not tightened or if you removed the calipers all to together and remounted them on the wrong wheel, the air is in the caliper because it can't get out.

How did you break a guide pin? Over torqued? Rusted in the bracket? Just curious.

Mobile mechanic? I also doubt the MC was damaged through bleeding/flushing. The pistons in the MC will only travel so far before they stop.
Yeah, they're at the top. Also, I had fairly good brakes before replacing pads. Basically I over torqued the guide pins, because I turned them the wrong way. Both. Haha.

But I got new pins and seemed to install them fine. The pins don't seem to be stuck, the caliper has fairly good movement, but since the new pads are in it's pretty limited movement. I read somewhere that a stuck pin could make the brakes spongy. Maybe I should invest in new bleeders. cheaper than a new MC and maybe I'll get lucky.
 

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Discussion Starter #7
You have air in the system. Try reverse bleed. Get a squirt bottle with a fine tip. Fill up with fluid. Turn upside down, purge and open the bleeder port. Slowly squeeze and fill while a buddy helps remove excess fluid from the reservoir with a syringe. This works better for me since air travels up. I had a motorcycle and this was the only way to get all the air out.
Good advice. Is it common for air to become stuck in the system on these? I've bled them about 30 times.
 

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You need to service the calipers. One or more may have a bad seal or a bad cylinder. You mentioned you had the problem after replacing pads but before the master cylinder. Thus it is not likely the master cylinder.
 

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Could also be the unwieldy vise grips- if you aren't closing the bleeder 100% while it is still actively squirting and the pedal is still in downward motion then you are creating opportunity for air to slurp back into the caliper.

Vacuum bleeder tools or a set of speedbleeder fittings make this a lot easier.

You can also improve things by attaching a bit of clear vinyl tubing to the bleeder nipple and collecting the fluid in a jar. keep the end of the tube submerged so that if you aren't quite fast enough closing the valve, the thing will only slurp fluid back in instead of air.
 

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if there's a tiny pin hole rust leak in the brake lines they'll work as if there is air in the system as well. i had it happen on a 97 legacy and it took a long time to figure out because the rusty lines were above the gas tank so the leak never showed until it finally blew out really good and had enough fluid to drain over the top of the tank and down. i replaced the master cylinder on that car too - thinking it was the MC!
 

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To the OP did you bleed the MC before putting it in the car? I have found you need to bleed the MC before it goes anywhere near the car or it will be impossible to get air out of the system.
To bleed the MC just fill the MC resevoir with brake fluid and put tigh fitting plastic tubing in the open ports of the MCl, run the other ends of the tubing back into the resevoir. Once the fluid is in the res push the shaft the peddle would be attached to, you should get bubbles going through the tubing. Keep doing it until the bubbles stop. keep the tubing in the ports until you are ready to connect the brake line to the proper port. Then go through what ever method you prefer to bleed the brakes. i prefer the pressure method. Using the two person method has lead to too many problems for me.
 

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Discussion Starter #13
Could also be the unwieldy vise grips- if you aren't closing the bleeder 100% while it is still actively squirting and the pedal is still in downward motion then you are creating opportunity for air to slurp back into the caliper.

Vacuum bleeder tools or a set of speedbleeder fittings make this a lot easier.

You can also improve things by attaching a bit of clear vinyl tubing to the bleeder nipple and collecting the fluid in a jar. keep the end of the tube submerged so that if you aren't quite fast enough closing the valve, the thing will only slurp fluid back in instead of air.
Yeah, I used the vinyl tubing with jar, and closed it before she let up, so I I know I wasn't adding air in the system.
 

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Discussion Starter #14
You need to service the calipers. One or more may have a bad seal or a bad cylinder. You mentioned you had the problem after replacing pads but before the master cylinder. Thus it is not likely the master cylinder.
You might be right. Any way to check this before having them serviced or getting new ones?
 

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You might be right. Any way to check this before having them serviced or getting new ones?
Fluid gets pushed past the seal and will end up in the rubber dust boot - which is the part you see when replacing brake pads. That rubber boot around the piston is a dust seal and should not be wet at all behind it. If it looks full of fluid then it's leaking internally.

There are rebuild kits that cost a few bucks and rather simple to do. If the caliper bore and piston aren't corroded (which happens, but i haven't seen it yet)- then there's really nothing to it - there's a seal around the piston and the dust boot, that's it.

or of course buy another caliper.
 

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Discussion Starter #16
Fluid gets pushed past the seal and will end up in the rubber dust boot - which is the part you see when replacing brake pads. That rubber boot around the piston is a dust seal and should not be wet at all behind it. If it looks full of fluid then it's leaking internally.

There are rebuild kits that cost a few bucks and rather simple to do. If the caliper bore and piston aren't corroded (which happens, but i haven't seen it yet)- then there's really nothing to it - there's a seal around the piston and the dust boot, that's it.

or of course buy another caliper.
If fluid was in there wouldn't I see a leak on the ground?
 

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Okay, backtrack time.

Brakes worked fine before the pads replacement.
Calipers were removed from the bracket but not disconnected from the hydraulic hose.
Broke two caliper guide pin bolts due to looking at the bolts backward.
After pad installation, system was flushed and brake pedal started going to the floor.
Repeated "bleed" sequences accomplished naught.
New master cylinder brought identical results.
Used open bleeding, hose bleeding methods. No change.

Car is ABS equipped.

How long since the last brake system flush?
What color was the fluid that came out the first time?
Will the pedal pressure increase with repeated pumping and all bleeder valves closed? Engine off and engine on? There is a reason I request engine on.
Did you go over all lines, hoses and joints in the system from the MC to the wheels and check for leaks? Including the portion of the rear brake lines that run inside the car and exit under the right side back seat, as well as the brake line that runs through the rear diff support.
Can you clamp off all the brake hoses at the wheel and check the pedal pressure? Does the pedal get hard? If yes, remove one clamp at a time and while someone is on the pedal. When the pedal drops, that would be the offending wheel. If no, then it rules out the calipers and leaves the MC, ABS or a leak.

Yes, if the caliper seals were leaking, the boots would be wet with fluid, as would the pad on the interior of the rotor.

I don't think pressure is getting passed the ABS control unit. I think the unit has a dump valve stuck open.

.
 

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Discussion Starter #18
How long since the last brake system flush? 2 years
What color was the fluid that came out the first time? light brown -Pale Ale
Will the pedal pressure increase with repeated pumping and all bleeder valves closed? Yes
Engine off? Yes
Engine on? No

Did you go over all lines, hoses and joints in the system from the MC to the wheels and check for leaks? NO leaks

Including the portion of the rear brake lines that run inside the car and exit under the right side back seat, as well as the brake line that runs through the rear diff support. Will do.
Can you clamp off all the brake hoses at the wheel and check the pedal pressure? Does the pedal get hard? If yes, remove one clamp at a time and while someone is on the pedal. When the pedal drops, that would be the offending wheel. If no, then it rules out the calipers and leaves the MC, ABS or a leak. Will look into it.
 

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If fluid was in there wouldn't I see a leak on the ground?
Yes, if the caliper seals were leaking, the boots would be wet with fluid, as would the pad on the interior of the rotor
Not always. Fluid can seap past the piston seal but it still needs to also leak past the dust boot before what cardoc said happens. I was thinking maybe all this exercising of the system compromised the seal....but if you "bled it 30 times"...or a fraction of that, then that is way beyond what dust boots could retain and you'd certainly see fluid loss.

Few people have seen a Subaru ABS pump failure so I'd follow cardoc closely on that.
 

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Will the pedal pressure increase with repeated pumping and all bleeder valves closed? Yes
Engine off? Yes
Engine on? No

OKay, this is narrowing it down. With the engine running, you should have an increase in pressure on the system due to the action of the brake booster using less pedal effort. Since the pedal stiffens when pumped engine off and holds pressure, that negates the hydraulics unless if after a minute or so leaving the engine off you try again and the pedal is soft again until pumped, then you would have a leak in pressure.

If you don't find a leak in the lines, and the clamp test results in no pedal drop to the floor, because the pedal will move a little with each removal of the clamp, then you need a brake booster.
 
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