Brake pedal stiffness?

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Fosty
Posts: 107
Joined: Sun Aug 05, 2018 8:01 pm
Car: 2001 Infiniti QX4 2WD

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How stiff are your brake pedals?

I just swapped out my shoes and pads, then replaced the brake fluid and I don't know if my pedal is sinking more than it used to.
It always was a bit softer than other cars I've driven, but it wasn't really a problem. But it's been a couple weeks since I drove it, and I just don't know if it's the same as before or worse.


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VStar650CL
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Joined: Thu Nov 12, 2020 1:25 pm
Car: 2013 Nissan Altima 2.5 SL
2004 Nissan Altima 2.5 S

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See if the pedal slowly goes all the way to the floor with constant pressure. Master cylinders often develop a "crud ring" at the base of the bores from the seal always stopping at the same spot, and the crud can sometimes tear the seals if you push the pedal to the floor during bleeding. The torn seals then cause "bypassing" under constant pressure. I always tell people to never push all the way to the floor when doing a bleed, go about halfway and then stop so that the seals never reach the crud. If your master isn't bypassing, then you might have just missed some air in the system.

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Fosty
Posts: 107
Joined: Sun Aug 05, 2018 8:01 pm
Car: 2001 Infiniti QX4 2WD

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Damn, I hope that ain't the problem. I did push it pretty low because it always did sink a bit lower than others but not really enough to concern me.
I read that air might be trapped in the ABS module so tried bleeding the ABS yesterday by pushing the pedal and loosing the nuts on the ABS module but it still sinks.

I'm going to try a few other things, but if those fail it might be time to look into repairing the master cylinder.
Thanks for the help!

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Fosty
Posts: 107
Joined: Sun Aug 05, 2018 8:01 pm
Car: 2001 Infiniti QX4 2WD

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I've also noticed this air sound when I press on the pedal since I've started doing all this work.
I read that a hissing noise could be a leak in the brake booster, but wouldn't that result in a stiff pedal?

It may have always been there but I never noticed.
Here's a video: https://www.bitchute.com/video/L8ToLezN1c13/

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VStar650CL
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Posts: 11929
Joined: Thu Nov 12, 2020 1:25 pm
Car: 2013 Nissan Altima 2.5 SL
2004 Nissan Altima 2.5 S

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Hissing when the pedal isn't pressed would indicate a leak. If it only happens when you press it, you're probably just hearing compensating air on the back side of the diaphragm.


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