I replaced the blades on my LP RCR2560 yesterday morning. I bought the cutter used so the blades were showing some wear and needed to be sharpened, so I decided it was time for new ones. I soaked the bolts in PB Blaster last week and they wouldn't budge. I tried a few days later with a 3/4 inch breaker bar and 4 foot pipe - nothing. So I decided yesterday to heat them cherry red with the acetylene - BAM! I knew that was the trick. Had them changed in about 45 minutes. I also used alot of ant-seize on the new bolts should they ever need replacing again. Best part is the cutter is silky smooth now and can barely hear it behind the tractor. I cut about 6 acres yesterday and it was pure joy...along with sunburn. 