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Whats wrong with my brakes??

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Old Oct 6, 2007 | 11:53 AM
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Whats wrong with my brakes??

Yesterday i replaced my front rotors and pads as the original fronts were warped. The rotors i used to replace mine were OEM w/ 10k miles on them (got them from a forum friend). They sat in a garage for couple yrs so they had some rust build up. I used wire brush as well as steel wool and scratched the rust off prior to installing. Obviously i was unable to get that smooth/mirror surface that the old rotors had due to the rough surface from sitting, but, i figured once the new pads squeezed that rotor for a few miles it would eat through that grit and smooth them out. After changing everything out, the warped feeling is gone but the brakes are REALLY soft and the stopping grip is way worse than before i started. Also, that gritty surface on the rotor has yet to rub off. Maybe i just need to drive it much more, i dont know. Also, the brake fluid prior to the install was on the low end, now it shows just over max. Is this the problem? Did the brake fluid not make it back through the plumbing causing the brake system to be weaker? Any help is appreciated. Thanks
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Old Oct 6, 2007 | 01:54 PM
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What kind of finish did you put on the rotors when you cleaned them up? Generally, you should use fine or medium emery cloth and polish with a circular scrubbing motion, leaving a visible whirly texture. If you tried for a polished surface, the new pads won't bed in properly.

Not too late - just get in there with some emery cloth.

Brake fluid deal is normal. As pads wear, fluid moves from the reservoir into the calipers. Push the pistons back so the new pads will fit, and the fluid goes back. Should not have come out higher, unless you had added some fluid at some time.

Ken
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Old Oct 6, 2007 | 02:35 PM
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Yeah the fluid is right back at the max line, that makes sense. I go back and give them a good wipe down with emery cloth. I just took fine steel wool to get the rust off and smoothed it out. I thought the pads would eat through the rest and smooth it out, guess not. Thanks, appreciate it
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Old Oct 6, 2007 | 04:05 PM
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Maybe you managed to get some air in the brake lines i would check that out
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Old Oct 6, 2007 | 07:26 PM
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Originally Posted by invasion08
Maybe you managed to get some air in the brake lines i would check that out
You know what, i had heard this from someone else as well. I am thinking this may be it because i went back and polished off ALL the grit on the rotors and the braking still feels soft/weak.

....Invasion, i have your avatar tattoed on my shoulder
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Old Oct 6, 2007 | 08:05 PM
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if you know how to bleed your brakes i would try that.
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Old Oct 6, 2007 | 08:55 PM
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as with any brake swap you need to bed everything in. just romp on them and it should be fine. meaning you should slam the pedal to the floor.
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Old Oct 7, 2007 | 12:04 PM
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....yeah fellas i think they just need broke in a bit. After 2 days they seem to be getting better and better. Not quite there yet, but they are getting better. I probably should have waited a week or so before i posted Oh well, thanks anyway.
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Old Oct 9, 2007 | 04:54 AM
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i hope you were joking about the romping the brakes...

break in the pads to rotors nice and easy. apply even pressure. and if brakes can be fully warmed up without coming to a full stop, the better. this process can be done easier on the freeway when changing new pads and rotors.

if you haven't got to measure the thickness' of those rotors, here they are.

--min. front plate thickness: 22.8mm on lathe, 22mm minimum
--front disc runout limit(if a dial indicator is accessible): 0.05mm
--thickness variation 0.015mm.

just at least a simple check of rotor thickness to make sure you're not at least running a thin rotor. use whatever thicker rotor you got and run down to any shop and see if they have any off-car lathe(cutting) service available...it shouldn't run you more than $10 per rotor.

good luck on ur new brakes.
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Old Oct 9, 2007 | 08:21 AM
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I would recommend maching the front rotors and verify they are within specs, then take some emery cloth to the pads to remove any glaze that might have formed and check it from there.
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Old Oct 9, 2007 | 10:55 PM
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http://www.zeckhausen.com/bedding_in_brakes.htm

do it!!!!


beers
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