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Old 12-22-2012, 12:18 PM   #1
seaneddy11
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Member#: 330431
Join Date: Aug 2012
Vehicle:
2005 STI
PSM

Default New brakes gone bad

Just had new brakes and rotors put on the Sti a month or two ago, did a lot of heavy breaking a few days ago, one because of idiots in traffic, etc. once I was home I could smell my brakes, also noticed them get extremely squishy on my way back. Now, three days after, the stopping power is minimal, doesn't feel strong. What happened?
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Old 12-22-2012, 12:34 PM   #2
Thunderpaw
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Join Date: Mar 2010
Location: Dallas
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2009 I don't know
Dirt

Default

What kind of pads?
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Old 12-22-2012, 05:16 PM   #3
Loyale93
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2012 Triumph 1050

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Quote:
Originally Posted by Thunderpaw View Post
What kind of pads?
This. We really need more information than you gave us. What kind of pads, what kind of rotors. Are your calipers stock? Have you looked at them? If so, what do you see? If not... why not?
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Old 12-22-2012, 09:51 PM   #4
Zaya
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1979 Z28 Camaro
Burgundy

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Like Loyale said we'd need more information, could have gotten seized and just burned the brakes out, not bled, brake booster. Plenty of problems that could be caused and have these symptoms. Sorry for the pointless post just trying to help you .
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Old 12-22-2012, 10:24 PM   #5
siadyang
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Chapter/Region: South East
Location: NC
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2012 WRX
2015 WRX

Default

Yeah, more info would be nice. What color is your brake fluid? If its bad, and when you pressed the pistons back in, you may have pushed up the contaminated fluid and messed up the master cylinder. That's the worst case scenario. I'd bleed the brakes if they feel spongy or dark in color. Check the color of the rotors too, you may have burned them up pretty bad and my just need resurfacing. Pads may be gone too, but just need more info. Hope this kind of helps.
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Old 12-23-2012, 09:05 AM   #6
SpamBot
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Quote:
Originally Posted by siadyang View Post
If its bad, and when you pressed the pistons back in, you may have pushed up the contaminated fluid and messed up the master cylinder. That's the worst case scenario.
Worst case scenario would be pushing the pistons back without cracking the bleeder screws, and forcing the brake fluid back too quickly through the ABS unit, which can damage one-way valves inside in the unit. During the "heavy braking" in traffic (too much speed in traffic wouldn't play a part in that, would it? ) the ABS may have activated, and now you have air in the system that is going to required secondary air bleeding to get out.
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Old 12-23-2012, 10:28 AM   #7
ryansx
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white

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If he is getting air in system because his abs activated it would have been soft peddle long before this one incident, they don't just randomly introduce air into the system when activated. Highly unlikely something is damaged from pushing piston back in without opening bleeder. Like they said possible seized caliper, booster, a brake line collapsing inside, leaking mc.
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Old 12-23-2012, 11:15 AM   #8
vision.dynamix
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Location: Boston
Vehicle:
2015 Subaru STI
17Forester / 18Crosstrek

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Quote:
Originally Posted by SpamBot View Post
Worst case scenario would be pushing the pistons back without cracking the bleeder screws, and forcing the brake fluid back too quickly through the ABS unit, which can damage one-way valves inside in the unit. During the "heavy braking" in traffic (too much speed in traffic wouldn't play a part in that, would it? ) the ABS may have activated, and now you have air in the system that is going to required secondary air bleeding to get out.
I have never cracked the bleeders while pushing pistons back in the calipers and have never had an issue.

Many pad changes, many track days, many bleeds. Not one issue.
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Old 12-23-2012, 12:43 PM   #9
Back Road Runner
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2004 Forester STI
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Placebo effect?

I would doubt what little you can do in traffic can harm the car. You just can't generate the heat necessary to do anything. The STI rotor size is pretty substantial and can absorb a lot of heat. You would have to be doing track days on sticky tires to do enough.

The only problem I can see is you buying super, super cheap pads, and they are simply junk. If you skimped out on pads by buying the cheapest junk you could find, then they could have problems with fading during heavy use and potentially glaze some and reduce friction for a period of time. However, your first comments should have been something about your brakes fading in traffic, not my brakes feel weeker days later. You said nothing about fade, so I suspect they never really overheated. In this case, your brakes are what they are, and I would think it's more of a placebo effect than anything else. Maybe they just have a lower friction coefficient than the old ones and your use seems off because they don't bite as hard as you'd expect. Pad friction can also be affected by temp and water.
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Old 12-23-2012, 12:47 PM   #10
Bacon117
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02 Silver Wagon
"Stage 2"

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Did you do a bed in procedure?
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