I have had an intermittent problem with my brakes on my 94' si. Occasionally the brake pedal will sink down to the floor while driving then upon release of the pedal, the pedal would regain normal pressure, only to begin sinking again. This symptom points to a failing brake master cylinder, however, after buying a Helms manual (best money ever spent on the car) I applied the master cylinder test which is to depress the pedal while the car is off a number of times until the pedal is stiff then to depress hard and hold for 15 seconds. Sinking of the pedal indicates master cylinder/brake line/caliper failure. My pedal did not move at all. I then proceeded to do the brake booster/check valve test, which is to start the engine with the pedal depressed and see whether the pedal sinks slightly, which mine did. There is no fluid change in the master cylinder, which points to no leaks, and since this is an occasional problem, it doesn't point to air in the brakes. However, I bled the brakes and regreased the rod seal which is between the MC and the brake booster with silicon grease, which stayed the problems for a while but they return. If anyone has any suggestions or a perfectly good master cylinder/brake booster for a 94 si WITH abs that they want to ship to Dallas , then please respond.

Thanks in advance


[Modified by Draco, 2:38 AM 2/12/2003]

 

Also, what are the differences between the master cylinders for the 92-95 civics?

 

Get a Teg brake booster and MC...

 

but won't that provide an imperfect pedal travel due to it not being proportioned correctly for my stock brake system?

 

bump...

 

Yes, and your point is?

But seriously - you have to remember that all of us have upgraded our brake systems to begin with, already throwing some parts out of balance.

If you're going to stay stock, get OEM replacements.

My $0.02 on your problem? Intermittent brake booster failure. I'll bet if you replace the booster your problems will go away.

Master cylinder problems do not "come and go", but because vacuum boosters are made with some rubber pieces, they can have intermittent failures.

No guarantee, but I'll bet this is the problem.

Shawn

 

thanks for your reply, but i am sticking with the oem 4 wheel disk brakes that came with my car. Will i have to use abooster from an ABS EG/EH or will any of the 92-95 civic boosters work?

 

Understood, and they're good. Many of us have upgraded from drums to what you have.

Any of them can be MADE to work if you get the master cylinder that matches, but since you have an original Si, get the Si booster replacement. I believe it's the same as the ABS booster, but I cannot swear to that. All you have to do is ask for the booster for the Si (warning, from Honda, that suckers expensive - you could find a good used one).

Shawn

 

hi, i have the same problem.....

the problem is the little rubber rings inside the master cylinder, they are leaking....

i will try to explain the problem with my bad english ( i am from brazil )

wen you light press the brake pedal, they will go down very slow, but will go till the end.... ( the rubber is not sealing is leaking inside the master cykinder)

but when you press the pedal a litlle hard the ******* rubber ring seal with the pressure applied to it....

so or you have to change the master cylinder or change the rubber seals.....

is anyway were i can buy these seals???

rely sorry about my english...

 

Brake master cylinder. My 2 cents.