[knightrider_916]

Spongy brake pedal when hot

When its hot out side and im driving, when i push my brake pedal it sounds and feels spongy. Anyone else have this problem? I have a 98 gt its got nothing to do with rotors or pads, trust me!

 

[tripleblack]

Brake fluid

Could be your brake fluid. As time goes on, your brake fluid becomes contaminated and needs to be replaced. Enough water contamination and you start to lose function. If your brakes get hot enough, the old, oe fluid will actually boil - creating a bad brake situation. This is also one of those maintenance items hardly anyone ever does. Replace all the fluid with high temp racing juice. Bleed all 4 calipers at the same time.

If this doesn't help with the spongey pedal, you may have a problem with the master cylinder or the vacuum booster. Check all the vacuum lines and ports first. If you are pulling plenty of vacuum, check the master cylinder.

Depending on your mileage, you may be nearing the end of the life span for your master cylinder/booster/calipers, etc.

 

[knightrider_916]

When its hot out side and im driving, when i push my brake pedal it sounds and feels spongy. Anyone else have this problem? I have a 98 gt its got nothing to do with the brake booster, rotors or pads, trust me! Please help its anpying as hell and its been doing it for years now!!!!!!!!!!!!!!!!!!!

 

[Fiat Freak]

Definately sounds like fluid, especially if function appears to be normal at low speed and temperature.

Brake fade should be expected with old fluid. Can expect to absorb water into the fluid, and rust the lines from the inside.

Check the lines to make sure there is no damp spots, even if you've been watching the fluid level. Then assuming there are no leaks....

Go get one of those vacuum pumps and purge all four wheels of the old fluid, making sure to not get air into the lines. Get some help for this to ensure that the reservoir does not run dry. This is your least expensive route to follow, and will most likely cure the symptoms. Additionally, everyone should be doing this every 2-3 years anyway.

Let us know if changing the fluid doesn't work.



I still want to know what a spongy brake pedal sounds like !!

 

[Guest]

How about the brake lines the goto the cal. ?

 

[knightrider_916]

what about them? they are oem and have never been replaced.

 

[knightrider_916]

ok i will try that next week and get back to you thanks!

 

[tripleblack]

Sqwuoosh

Sqwoosha, maybe. Sucking/liquid sound. Not loud. Last time I heard it was in a 1977 280Z whose brake booster was leaking vacuum. Time before that, a 75 Volvo DL with a bad master cylinder. Funky sound. Hope this guy's brake problem doesn't go that far.

tripleblack

I still want to know what a spongy brake pedal sounds like !!