Are u saying your rears last 242K miles.?I did this about a month ago to my rear brakes and the slide pin was also the problem. It was frozen to the caliper, after Brake cleaner, PB Blaster, a BFH and then an air hammer the caliper finally came loose. So definitely lube the slide pins or you're gonna have a headache next time. Also, my 2001 HL has 242,000 miles on it which could also be a factor as to why it was so stubborn.