I top the car off with fluid and press the brakes. The peddle stops, and seems to sink slowly to the floor. My question is, could there be a leak inside the cylinder itself, cause the fluid to not leak out onto the ground? Should I just spend the money and replace the Cylinder, even though I don't know if this will fix the problem? Thanks for taking the time to read and comment on this.
Another Question about Break Master Cylinder.?
First let me say that brake fluid does not evaporate and if you are having to add to the reservoir, you have a leak. From what you have said so far, I tend to think that your leak might be wash by. Let me explain, when a master cylinder ages the seals allow fluid to slip past and we refer to this as wash by. This fluid ends up in the power brake booster and eventually causes it to fail as well. Remove the master cylinder without removing all of the lines and look for fluid inside the booster. If this is the case, go ahead and replace the master. Remember to bench bleed the new master cylinder prior to installation. Good Luck
Another Question about Break Master Cylinder.?
i hope you mean brakes not breaks (sounds like they are already broken).
IF there is nothing leaking out of the rest of the brake system including the slave cylinders on the axles then it must be the master cylinder.
The system may be leaking onto the exhaust system, and the heat would evaporate any liquid.
If you can not find any visible leaks I would try to bleed the brake system start at the wheel farthest away from the master cylinder (right rear) and work your way forward. If nothing is leaking it has to be air in the system. Also check the diaphragm in the lid of the master cylinder if so equipped for cuts or holes.
Fluid can leak into the rear drums from the wheel cylinders and be hard to detect unless you pull the drums off. Also there is a seal at the back of the master cyl and brake fluid can leak into the power brake booster, you can unbolt the master without pulling off the brake lines and peek at the seal to check it. Good luck! A sinking brake pedal can sometimes be cause by a master cyl leaking internally but in that case you would not be loosing fluid.
