1999 f250 PSD ZF6 306K

Oil is dripping down the caliper and into the inside of the wheel. It is not brake fluid. Caliper, pads, rotor, and parking shoes are all new. Could this be the seal that is on the inside of the hub? Along with that bearing...

 

Sounds like a rear axle seal to me. I had one leak on my 2001 F250 at one point and it contaminated the brake pads and everything else back there. Not sure what the setup is on a 1999.

 

Defiently the axle seal, stop driving ASAP and fix it. Your gonna need to do both sides becase the gear oil soaks the parking shoes, rotor, and brake pads so both sides need replacing. I'd also replace the axle seal on the drivers side due to age of the vehicle. If the backing plates are rotted do them also since so you wont have to do the seals again if your backing plates rot off a year or so from now

 

 

You can use 500 cans of brake clean, the shoes are shot period. Once oil gets on them they are toast, and the parking brake should work properly after adjusting. Mine are original on my 2004 with 165k and they will hold my truck and 18ft trailer no problem at all on any hill