i did a quick seach but nothing jumped out at me...

on my 92 ex 4dr 5spd 217K on the ticker. i have noticed something that worries me a lil. when it gets warm outside my brake pedal will occasionaly go almost to the floor upon application. not every time but somtimes. and only when its warm. when it fades i am able to pump the pedal a couple times and the "fade" goes away. i noticed it last year when the ambient temp was in the high 80's and up.

for example i work 2nd shift so i go to work in the heat of the day, and on my way to work once or twice the pedal will fade. this is without aggressive driving, just normal application. now when i get off work in the evening i notice that this brake fade does not happen, or at least i can't remember it happening. i never had it occur all winter.

well last week with the temp only in the high 70's my problem returned. im almost certain that it's temp related.

now i don't know a whole lot about this sort of thing(just enough to be dangerous.) i do know that brake fluid is hydroscopic, it absorbs water over time which lowers its boiling point. now i'm thinking that that would cause my pedal to fade.

your thoughts? opinions? would a good brake bleed to flush out all the old fluid have any affect? could that damage my MC, flushing that much volume of fluid through it in one sitting? or is this somthing else entirely?

on a side note ever since i have owned the car when it's been really really hot (upper 90's) the ABS light will sometimes (maybe once a month) come on. but once the car is turned off and restarted the light does not come back on.

the MC and ABS reservior's are both full to the marks. and the pads appear to be in good shape.

thanks for reading and any help you may have to my situation.

 

brake master is leaking internally,, you need to replace it

there is a write up on our DIY section ...

 

Flush/bleed with fresh fluid might fix it but only for a little while. The real solution is a new master cylinder.

 

i don't doubt your opinion, yall know alot more about this stuff than me. its just odd to me that it only happens when its warm. i have had a MC go out on me b4 on my old civic, it would just fade randomly. im gonna look into it. thanks.

 

I wish I could completely understand the temperature thing, but that's exactly how it happened to me ('95 Integra); itonly screwed upwhen it's hot outside.

 

i was talking to guy at work and he put out the idea that when it warms up and causes the fluid thin out more, along with the age and absorbed water causing it to leak by and fade? could just be complete jibberish but it almost makes sence to me.

 

It's not jibberish, but it is ageneralization that doesn't make me feel like its a complete explanation.