My friend has 2001 ford expedition. She's been complaining that her brakes aren't working as well as they should. I notice an oil puddle around her rear passenger side tire. My immediate thought was brake fluid, but her fluid level was filled perfectly. And when stepping on the brake I do not see fluid seep out.
The fluid was all around the inside & outside the caliper, rotor, wheel bearing, Everywhere. Most notable thing was that when I took the brake pads out, the brake material on both completely separated from the metal. Is that something brake fluid can do? How do I know if it's a caliper leak or axle seal?
You can pull the caliper off and check under the the piston dust boot for fluid leakage. There should be zero fluid leaking past the piston. However if the brake fluid level is not going down the axle seal is the primary suspect. It would not be a bad idea to check the oil level in the differential.
It's a rear axle seal. Probably means the axle bearing is shot as well. The oil you are seeing the gear oil from the rear differential.
gear oil is viscous (thick). It also stinks.
brake fluid is thin.
