My brakes seem to lose pressure, especially on hot days.

It's not like when the booster fails and you just don't have power brakes.. As I understand it, a bad booster just takes power brakes away and you are left with a very stiff pedal but working brakes, right?

When I'm coming up on a light if I am on the pedal trying to come to a stop, the pedal sinks almost all the way to the floor. If get off the pedal and step bad down on it, I seem to get (some) pressure back and can stop fine.

The brakes have never gone completely 100% out, either. When I seem to have lost pressure completely and the pedal hits the floor, there seems to be some kind of last ditch system that kicks in (or something) that locks the wheels immediately, BLAM.

Not sure if it matters but the *** **** ****ing ABS light has been on for a month or so.. but the car first had this problem last summer when it was well over 100 degrees outside.... the problem went away though

Now, it has started doing it even when it is not hot outside. It got a little better when I tried bleeding the brakes off, for awhile, and then got worse again.

So now do I need to just throw a master cylinder on it or do I need to try and run down a tiny air leak or is the fluid maybe real old and worn out(maybe boiling, maybe has moisture in it?).... or what??

The most confusing part of this is that the engine RPM being higher seems to help the brakes work better.. pointing me toward the booster... but this CAN'T be the booster, can it???


One more clue, if I read this one article right, I can take the cap off of the brake fluid reservoir under the hood, on the driver's side- and no matter how hard I jump on the brake pedal, no fluid moves in the reservoir-- much less does it squirt out of there as I (think) it should----- does that confirm that it is a bad master?

Any ideas about what caused the ABS light to come on, in the middle of this all?

Thanks!

 

When at a stop. Hold steady pressure on the brake pedal - does it slowly sink to the floor? Eith way it does sound like the master is giving up.

Just the service connector and get the codes from the ABS. Let us lnow what they are.

 

1) Spongy brake pedal that gets better with pumping the pedal = air in the brakes. Bleed the brakes.

2) Nice hard pedal but it slowly & smoothly sinks to the floor when holding at a long red light = bad master cylinder.

Either way, it doesn't hurt to try bleeding the brakes. But if it behaves like my 2nd description (bad MC) then bleeding will probably turn out to be a waste of time.

How about leaking fluid? Are you losing any fluid inventory in the master reservoir? Brake fluid dripping on the garage floor?

 

I'm not sure if I described it properly.. It's not like I can pump pressure back up, it just sort of gives me some pressure back if I get off of the brakes for a second...

Steady even pressure on the pedal while moving OR at a stop = slowly (and sometimes not so slowly) sinking to the floor

Do you mean the OBDII connector you can put a jumper in to read BCM codes? Or is there a different one I can mess with to find out why the ABS light is on??

I'm trying to remember, there's engine control module, body control module and powertrain control module... right?

 

Yeah I don't think I described it too well. I made it sound like I can "pump pressure back up" and I really can't.... I am confused to hell as to why the problem got better for a half of a day after I bled them though

I haven't lost any fluid from anywhere ever, at least that I'm aware of.. Never had to add any thus far and the level stays the same so that is nice, at least!! In another car, I tried pressing the brake with the reservoir cap off, and brake fluid shot out all over the hood and all over hell.... Here on this car I do the same thing and there is NO movement in the reservoir, engine on or engine off. . .. I don't know where I got the idea that means to blame the master though

I'm pretty sure we're all agreed on blaming the master cylinder here.. This guy I know is willing to throw a used one on there for $35 including labor, which ain't too bad. Apparently he has to bleed the thing before putting it on the car and then bleed the whole system.. so I think $35 is pretty good.. plus if it goes out again, he'll probably throw another one onto there for me for free- he's good like that.

 

It does sound like the master cylinder is going out. Sounds like your friend knows something about it. Be nice to him, and help him out. You can learn a lot helping out. He will probably need you to pump the brake pedal for him when he bleeds the brakes.

 

I'll help him if I can, for sure... Do these fail pretty often on accords? He will do the master for $35 which includes a used one and the labor OR he will do the labor for $25 and the cheapest reman I could find is $40 or so ...... I'm really not sure whether it's better to go with a used real one or a reman pos $40 one

Since he would probably put another one on if this used one goes out, free, I think I will go that way