Driving Saturday night and hit the brakes, pedal felt soft... hit the brakes again and pedal went all the way to the floor. If I pump the pedal a coulpe times it gives me a little resistance and then the pressure goes away again. pedal also gets stiff when vehicle is shut off. Res is full of fluid; I think its the master cylinder, but I'm not 100% sure. I tried searching to see if there has been anyone with common issues and really couldnt find anything. I have about 130k on the car; I'll get it looked at--at work today.

Thoughts?

 

Brake master cylinder

 

You have a serious problem. Somewhere in your brake system that has been a failure of either a brake line, a fitting, or a seal. It has to be one of those things. First, a brake line may have broken. This will cause an instant loss of fluid when you hit the brake pedal and no pressure at the caliper the line leads to. Fortunately because of some interesting plumbing and such you should not lose your brakes completely when the line breaks, not immediately that is. You may get a few stoops out of the car, but that will be it. The next thing that could be wrong, but almost never is the problem, is that a fitting may have failed - not likely but possible. The effect would be the same as a brake line breaking. The last possibility is that a seal has failed. This is not an uncommon failure at all and its certainly not limited to Acuras. There are seals in the Master Cylinder and in the individual break calipers. There will be fluid loss from failed seals too, but sometimes they lost fluid isn't obvious. In any event the three different things have the same effect when failure takes place. In every case it becomes impossible to pressurize the system and without that pressurization you have no brakes.

Whoops, maybe I should have said this first. This is, at the most basic level, how the system works.

First you press the brake pedal. The pedal is connected via mechanical linkage to the master cylinder. The pressure from your foot is relayed to a rod in the master cylinder that pushes on a piston. The piston has a seal so that pressure is not lost as the piston pushes against the brake fluid contained in the cylinder. The fluid then travels through the lines and fitting to the calipers. If there is a break anywhere in the lines or fitting the pressure will be lost. Finally the lines enter the calipers and there it pushes agains the caliper pistons - each of which also has its own seal. If that caliper seal fails the pressure and fluid will be lost without moving the piston. That piston, but the way, presses directly against the brake pad and moves it into the caliper to effect braking on a working system.

 

It's definitely a hydraulic leak and most likely the master cylinder. Look in under the dash and see if the master cylinder is leaking inside the car.

 

Josh, its not leaking into the car...

 

If the fluid is not going down nothing is leaking. But air is coming into the system. Sounds like a bad booster/master to me. I had a few fail on Fords & that is what happen. Pedal to the floor no stopping but fluid was full.

 

read my thread about a failing MC.
https://acurazine.com/forums/showthread.php?p=12765078

 

this happened to me last weekend. at first i thought it was the caliper seals gone bad but after checking it out it was my brake line leading into the caliper that broke. decided to replace both sides and ordered new brake lines today and gonna go pick them up tomorrow

 

Stainless steel lines I hope.

 

the one that broke was a stainless steel line. i orderered OEM ones since i don't really care about upgrading anything on this car anymore. as long as it gets me to work and back, that's all i need

 

What lines were you running?

 

just like everybody else mentioned already check your brake lines first, if no leaks or rust then it's your master brake cylinder, pretty easy fix

 

Would like to know what lines too as I plan to buy SS lines in the future

 

^head to excelerate

 

they were Russell lines that were on the car for about 5 years. it was the drivers side that got frail and disconnected. put in the new lines today with new rotors/pads and it's like new again

 

Interesting. I think Im running Russell lines. Ill have to keep an eye on them.

 

http://store.excelerateperformance.c.../i-251977.aspx

 

It was my SS brake line that was leaking. I ordered the Wilwood BBK a few years ago and the brake lines were a little bit too long... well, the brake line ended up resting on the CV boot and rubbing thru the brake line.

 

Since the BBK does not accept a banjo bolt, I had to get a line custom made (since the Cl is my only mode of transportation), I could not wait for one to be shipped to me.

 

glad you found your leak.