This is a 2002 Workhorse W22 chassis, 22.5 inch rims. Black plug is definitely not clogged. I have used a mobile mechanic in Florida who worked on rigs his whole life. He used the Napa part. I then used a very well-reviewed commercial truck shop on the Chesapeake Bay and they used the National part equivalent, said the seal went on just fine. Drove it 100 miles today to the next campground and ALL of the oil had leaked out by the time I arrived. Nobody nearby can work on it so I have ordered the original STEMCO seals to a place in Boston to get them installed there. It is a 7.5 hour drive and I will just pull over a lot and continue to put more oil in. I don't really have any other choices at this point, but I am beyond frustrated and it is costing a small fortune for a stupid $40 part.
BTW, the oil is leaking on the inside all over the rim and caliper. It is not leaking on the outside at all.
