1988 Accord Brake Problem, no stop! fast idle

[SpecV25]

I bought an 88 Accord for a winter car. I have been fixing it up all week and now I am stumped. There is a lack of braking power. With the engine running the pedal goes almost all the way to the floor, but with the engine off there is good hard pedal. While driving there is a lack of braking power, and pumping the brakes seems to make the engine stumble. I replaced the master cylinder, thoroughly bled the system and that was not it. Pads are good all the way around. No leaks in the system either. Any help would be greatly appreciated! Oh the the other issue I noticed was the this car likes to idle at about 2000 rpm, but sometimes it idles at 1000 (still high), it is carbureted, any ideas?

[somick]

If your engine stumbles during brake pumping it points to a defective brake booster since it uses engine's vacuum to boost the power.
The second idea:
I had the simillar things in my old Ford. It was a warn push rod on the master cyllinder.
Or it might be the combination of both.
I hope this will point you to the right direction.

Sam

[jeffcoslacker]

Cap the vacuum line to the brake booster and see if the engine idles down. If so, there is a hole in the line or a blown diaphragm in the booster. Leaning towards internal damage to the booster, as a bad supply would just make the pedal hard...

I've seen a few Hondas where the booster was bad, and it would actually suck brake fluid through the rear seal of the master cylinder under high engine vacuum (like dropping the throttle suddenly at high rpm in low gear on a manual trans model), causing a cloud of white smoke from the exhaust and sudden loss of all brake fluid from the resevoir....you aren't at that point yet, but sounds like you are getting there...

[SpecV25]

Thanks guys, I'll have to do some more investigation this weekend.

[music_freak9728]

ill tell you ive had the same problem. i have an 88 accord and mine does the same thing. i replaced the breaks and mine seemed to stop doing it but sometimes it still does.