spongy brake pedal

[Niko97RS]

i checked out my pads today....they have like 1/2 inch left so its not my pads being worn down.

what else could cause a spongy brale pedal?

could it just be fluid? or does the master cylinder have anything to do with the pedal response?

[Daviselk]

Re: spongy brake pedal

spongy pedal is casused by air in the brakes... bleed your breaks properly and you should be fine

[Camaro Dom]

Re: spongy brake pedal

and by properly, he means dont forget to get a tech tool to activate the ABS motors. As long as you're going to be bleeding and getting the tool... just drain and refill the whole system. might as well...

[ssms5411]

Re: spongy brake pedal

Top off your brake fluid, make sure your not leaking any where. As your pads wear down you will have to add more fluid to maintain the pressure in the lines, since they are compressing more.

[zlexiss]

Re: spongy brake pedal

As your pads wear down you will have to add more fluid to maintain the pressure in the lines, since they are compressing more.

Huh?

As the brakes wear down, the fluid from the reservoir makes up for the extra fluid sitting in the caliper piston cylinder. Unless you have a leak, there's usually enough that if the fluid was topped off to the right point when the brakes were new, there will still be enough fluid left to make sure no air gets into the master cylinder.

If the reservoir was so low on fluid that he was getting air into the system, the brake light comes on in the dash as a warning, though I'm not sure what year this became effective in.

Yeah, there will be a little more compressibility in the pedal due to the extra fluid in the calipers from worn pads, but not enough to create a bad feel. Unless the fluid is real bad.

I'm with Dom that a proper flush is needed. I don't think you need a drain and refill, but make sure you get all the air out and all new fluid in. I use ATE Super Blue and Type 200, they're excellent fluids and come in two colors (blue and gold), so you can alternate the two and easily see when you've gotten all the old fluid out.

[RyanAndyBob]

Re: spongy brake pedal

It's either bad fluid or bad brake lines. I bet its the break lines though This is from the modifications section of this awesome web site:

"During heavy braking the pressure of the brake fluid inside these rubber hoses builds up tremendously. Again, because most people brake heavily only rarely, this is not an issue for average drivers. However, during high-performance autocross or road course racing, the brakes are applied again and again, causing consistent high pressure buildup inside the rubber hoses. As a result, the hoses expand slightly, alleviating some of this pressure. This pressure loss results in a spongy feeling on the brake pedal and mushy braking performance. An effective and relatively inexpensive solution to this problem is to install braided stainless steel brake hoses. These are far stronger than rubber and do not expand during heavy application on the pedal, yet are flexible and work fine even when all four wheels are jumping up and down on bumps. The noticeable result is a stronger, stiffer feeling on the brake pedal."

Hope that helps!

[Niko97RS]

Re: spongy brake pedal

thanx guys

btw i accidentally mixed reg with synthetic brake fluid lol

stupid guys at autozone and me being up at 8am i bought the wrong ish.

seems to be fixed now though :)

[DAS BOOT]

Re: spongy brake pedal

yep swap the fluid...


I thought my brakes were done, 60k on the rotors, 30k on the pads... I bought all new stuff looked at it and thought, might be cool. looked at fluid, green/black


swapped the fluid, my brakes feel stronger/better then any other car I have driven with exception to my dad's vette.

lasted another 20k so far still feeling strong... but rotors are getting thin, brakes fade alot faster.

[v6mOtOrhEAdftOp]

Re: spongy brake pedal

thanx guys

btw i accidentally mixed reg with synthetic brake fluid lol

stupid guys at autozone and me being up at 8am i bought the wrong ish.

seems to be fixed now though :)

Just FYI, most fluids as long as they are DOT 4, are compatible, synthetic or non. Just something to remember