My goal for this weekend was to get the clutch master cylinder apart. After 24+ hours of soaking in the PB'laster the cap wasn't any looser so I tried to soak it in brake fluid, brake fluid is pretty corrosive so I was hoping that it would corrode or revitalize the crystallized brake fluid that was gluing the cap stuck. No luck there either. We threw the whole cylinder in a vice, nailed the vice down to prevent slipping and cranked on it with a pair of channel-lock pliers. Still no movement. So we tried an old mechanic trick to breaking loose rusty parts: temperature cycling.
The idea is that metals (like all matter) expand at higher temperatures, so you heat the metal so that the hole opens up more and you can break the piece loose. I cycled the cylinder by letting it air cool a little after it got blasted by the heat gun (at up to 1300 degrees Fahrenheit) then dunked it in warm water in an attempt to quickly contract the expanded metal to break the oxidization loose. After three or four rounds of 15 minutes of heating, then 5 of air cooling then dunking it in the water, I left the heat gun on the cylinder for 45 minutes, grabbed it with a pair of pliers and dunked the cylinder body only in the water , making sure to keep the cap out (I would not recommend this unless all else fails, the temperature shock can crack or shatter the metal you're working with).
After it cooled in the water for a few seconds I threw it on the vice, tightened down on the cap and turned. Finally I got some movement, a few more cranks and it was loose enough to remove with just my fingers (after cooling the cap of course).
I left the cap off and soaked/sprayed the whole cylinder with brake cleaner and set it aside to break down anything inside so when I go to rebuild it I won't damage it when pulling out the push-rod.
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