Q: Brake pedal feels mushy & goes almost to floor.

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Only leak I can see/find is rt. rear axle inner seal. Can differential oil be getting on brake pads. (rear disc brakes). Don't see any oil on pads or rotor.

My car has 192000 miles.
My car has an automatic transmission.

Liquid (oil, water, grease) contaminants on brake pads do not affect pedal travel, although they might increase stopping distances. Most brakes systems are designed and/or located such that leaks from nearby systems can’t contaminate the pads. At any rate, a quick visual inspection by a mechanic would answer that one way or another. Your excessive brake pedal travel is due to external leaks, air in the system, ballooning rubber hoses that have failed, a clogged proportioning valve, and/or a failed master cylinder that is leaking internally. Check the fluid level in the master cylinder reservoir. If the fluid level is above the minimum, you probably do not have an external leak. Initially, a mechanic would try to expel all air from the brake hydraulic lines and re-test pedal height and also check rubber hoses for failure. Once all air is removed, and external leaks are eliminated as a possibility, if pedal travel is still too great, it is possible the master cylinder is leaking internally. If you want these steps performed by a certified Mechanic, dispatched by YourMechanic right to your location, please request a low brake pedal inspection and the responding mechanic will get this resolved for you. If you have further questions or concerns, do not hesitate to re-contact YourMechanic.

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