"Spongy" Brakes?

trickdriller · 10-13-2009, 09:56 AM

I have an 03 GT. For as long as I've owned it, my brakes have had this weird sound when you listen closely to them. "Spongy" is the best I can describe it. It happens when I step on the brake pedal once the car has been warmed up and running a while. The hotter it gets, the more weird it sounds. Almost sounds like there is air in the lines. Kinda like bubbles running through a hose with liquid. Anyone got an idea on this one?

And as a side note, I bought Duralast Gold Ceramic brake pads and got a decrease in stopping power. I have stock brakes on this car and turned rotors, but really? Should it have gone down that much? Just wondering.

Thanks gents.

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WannaBeGearHead · 10-13-2009, 10:48 AM

When you pushed the rear caliper pistons back in did you line up the notches on the piston so that they were at the clock location of 12 and 6?

You could have got air into the system but I wouldn't think you did unless you pulled the brake line off the caliper. You could always try and bleed the brakes to check if there is air in the lines.

Does the brake pedal feel the same as it did before you put the new pads on?

trickdriller · 10-13-2009, 11:11 AM

Yeah, it really does feel the same as it did before. MAYBE a bit softer, but not much. As for the notches, no, I didn't even notice them. I have never done that on any brake job of my Mustangs. What is the purpose of doing that?

And yeah, I could bleed the lines. But it is such a PITA that I would rather not if I can get away with it.

EDIT: I just re-read your post. I didn't work on the rear calipers that time. Just the front.

Brute03 · 10-13-2009, 11:31 AM

does the sound you're hearing sound like rushing air? the brakes on my old silverado sounded like that but it was normal

trickdriller · 10-13-2009, 11:43 AM

No, not like rushing air. Almost squeaky, but not that high pitched.

Xemeth · 10-13-2009, 12:27 PM

The hydroboost on these cars make the braking feel weird. They use hydroboost on some of the bigger GM trucks, and customers complain that the brakes feel soft sometimes, but it's a normal feeling on the hydroboost systems.

cliffyk · 10-13-2009, 12:32 PM

Quote:

Originally Posted by Xemeth

The hydroboost on these cars make the braking feel weird. They use hydroboost on some of the bigger GM trucks, and customers complain that the brakes feel soft sometimes, but it's a normal feeling on the hydroboost systems.

+1, it took me a while to get used to it--I bled the brakes 3 times before realising that was just the way the hydroboost system feels...

945LSTANG · 10-13-2009, 12:55 PM

Quote:

Originally Posted by trickdriller

Yeah, it really does feel the same as it did before. MAYBE a bit softer, but not much. As for the notches, no, I didn't even notice them. I have never done that on any brake job of my Mustangs. What is the purpose of doing that?

And yeah, I could bleed the lines. But it is such a PITA that I would rather not if I can get away with it.

EDIT: I just re-read your post. I didn't work on the rear calipers that time. Just the front.

just head over to ACE and get a couple feet of their silicon tubing to slip over the bleeder valve. it makes the job a breeze and only costs 40 cents.

Hangwire · 10-13-2009, 04:42 PM

When I bought my car 14 months ago I dont....recall.....it doing this. But it does EXACTLY what you are describing now. It feels and sounds very "spongy." That is the best way to describe it....but I still have great braking power even though my rotors are shot.

cliffyk · 10-13-2009, 05:55 PM

Quote:

Originally Posted by Hangwire

When I bought my car 14 months ago I dont....recall.....it doing this. But it does EXACTLY what you are describing now. It feels and sounds very "spongy." That is the best way to describe it....but I still have great braking power even though my rotors are shot.

I didn't notice it until I the changed rotors and pads. I never broke the lines, but when it got back together the brakes seemed spongy when stepping on the pedal--vehicle stopped. I bled it 3 times before convincing my self it was just something I hadn't noticed before...

BTW--I had to change the front rotors because I warped them shedding 55 MPH (the 55 MPH between 125 and 70) in response to a threat detector alert--late one night on I-10 between Tallahassee and Lake City, I bet those rotors were glowing red when I passed by the radar gun...