Brake pedal after first application

[Bill Mc]

question on my brakes for ya: 91 SHO. When I first hit the brakes, there is the normal feel. When I hit them again about 2 seconds later, it feels like the brakes grab quicker, like the pedal has no travel before the brakes are applied. I don't think it is a vacuum booster issue - the brakes feel like they are power assisted the whole time. I just lose any extra pedal travel, which feels weird. Perhaps the pedal isn't coming back up as far, but I'm not so sure about that. This car had sat for a while and I had bled everything and replaced the rear hoses. It brakes very well in terms of stopping when I need to. thanks for any thoughts.

 

[zak]

I thought the 91's and 92's had master cylinder issues? Never owned either year.

 

[OG-SHOguy]

question on my brakes for ya: 91 SHO. When I first hit the brakes, there is the normal feel. When I hit them again about 2 seconds later, it feels like the brakes grab quicker, like the pedal has no travel before the brakes are applied. I don't think it is a vacuum booster issue - the brakes feel like they are power assisted the whole time. I just lose any extra pedal travel, which feels weird. Perhaps the pedal isn't coming back up as far, but I'm not so sure about that. This car had sat for a while and I had bled everything and replaced the rear hoses. It brakes very well in terms of stopping when I need to. thanks for any thoughts.

Try changing out the fluid with new in the entire system... i bet either the fluid is old and bad or it has a little air or contaminates in it... either way a fluid flush wont hurt... good luck!

 

[rubydist]

If I understand what you are saying, its normal. When the brakes are released for a while, the pads get pushed away from the rotors a little, so the first application of the brakes takes more pedal travel. If they are reapplied a second time in short order, then the pads have not moved away from the rotors much, so there is less pedal travel to get the same braking force.

 

[OG-SHOguy]

If I understand what you are saying, its normal. When the brakes are released for a while, the pads get pushed away from the rotors a little, so the first application of the brakes takes more pedal travel. If they are reapplied a second time in short order, then the pads have not moved away from the rotors much, so there is less pedal travel to get the same braking force.

Brakes inadvertently work on friction as well, so a cold pedal would feel dramatically different than any pedal after that because of the friction build after the first "cold application" ...I agree, sounds like a normal cold pedal feel.

 

[Bill Mc]

Thanks guys! Yeah, it feels different than any other car I drive. Like I said, this car sat a while, so I wonder if you guys are right and also the piston is taking longer than normal to retract a bit further. It doesn't feel like the brakes are hanging up or anything. Rock has Morse calipers on clearance.: 4311A....hmmm: http://www.rockauto.com/en/moreinfo.php?pk=2755590&cc=1138665&jsn=10516

I don't think it is related, but I have an ABS code of 26 RH valve body input. The valve body isn't cheap to replace!