Brakes don't work consistently

[Galland1928]

I searched this forum and the internet but didn't find anything specific to the issue I'm having.

I have an '04 Honda Pilot with 102,000 miles on it. When I press the brakes, they are solid until the rpm's of the engine drops. When the RPM's drop, the brakes depress further which causes the vehicle to slow down much faster.

If I rev up the engine while doing this, the brakes stiffen back up and then depress again when the RPM's drop back down.

Any idea's what this could be?

[94eg!]

Sounds like it might be a bad brake booster. I've not personally seen a booster go bad, but the fact that the rate of power-assist changes with rpm points to the booster.

A bad master cylinder would have the pedal drop like you described, BUT the car would not slow down faster. It would slow down less. You would then have to pump the pedal to build pressure again to keep the vehicle slowing.

Look into getting the brake booster checked out...

Its the large round thing (#6) bolted to the fire wall behind the brake pedal:

Part prices & numbers: Part Detail)

[hkellogg]

Boosters do go bad, but not so common, I had one go bad on my 96 jimmy, a common diagnosis of a bad booster is a very hard pedal and very little brake. Your car would also stall when you brake.