I had a mechanic look at my poor braking. I checked everything myself, but couldn't find a problem so I caved. The mechanic said the left rear axle seal has a slight leak and the gear oil has gotten all over the brake pads. He says I need to replace the pads and the drums. Is this normal, can't they just be cleaned with brake cleaner? Are they permanently contaminated with gear oil?

Secondly, is it common for the seals to go out. I replaced that same seal 2 years ago when it and the bearing went out. I used factory parts to replace. It was far more obvious before, I could see gear oil every where. This time a simple visual doesn't show me anything.

Maybe I just screwed the job up.