Honda Car Forum

I was at a red light and the brake pedal just went down. Then I heard some kind of air sound coming from under the pedal when I pressed... I took it to the shop.... what do you think the problem is....The mechanic said he had to change both the front rotors, brake pads, and a caliper and a hose... he said only after he did this would he be able to know if the master cylinder needs replacing or not.... WHat do you think... is this an honest mechanic... thanks again...Alex, nyc

I think it's the master cylinder,unless you have a leak on the ground from one of the brakes or a brake line.the problem is purely hydraulic. if you have a firm pedal then the pressure will be put on on the caliper to the brakes. the hydraulic system can get air in it and the pedal will be lower than normal. but since the pedal went to the floor instantly, you had a leak in the caliper or hose or fluid bypass thru the master cylinder.if you check your brakes on schedule you shouldn't need to replace the brake pads or your rotors at this time. He should show you how much wear the brakes had and the rotors and if they should be replaced.sounds like he's trying to get the hydraulic system from leaking and then see if the master cylinder is leaking, which is right.

Bullcrap... get out of that place ASAP. This sounds like the classic master cylinder issue. Should be around $400 to fix, but the other parts you mentioned will probably run $900 and they'll just come back and say it's the master cylinder.

It's the vacuum booster. The air you're hearing is a leak in the boosters diaphragm.Quick way to check.Is there any fluid leaks? noIs the fluid level low? noWith the engine off, do the brakes work? yesTurn the engine on, then turn the engine off, apply the brakes, is the pedal hard to push? If you push on the brakes again, does it get harder"Do you only hear the air sound when stepping on the brakes? yesThese are all symptoms of a bad booster.If you need to change the booster and you have a lot of miles on the car and the brake fluid hasn't been regularly flushed, you might want to change the master cylinder at the same time. They shouldn't charge you any extra labor, since it has to come off to get to the booster. The labor charge just to change the master is probably equal to the cost of the part itself. If the pedal goes to the floor while keeping pressure on it, the master cylinder has an internal leak and need to be replaced but that wouldn't make any air sound

Go to another mechanic, this one wants you to fix everything then troubleshoot? That's not right. Go to a mechanic that will "troubleshoot" the problem first then give you a list of the problems. Not the other way around. It could be a brake line, brake booster, or master cylinder. You might've just left the fluid and got air in the lines and all you need to do is bleed the system.