To bleed the old DOT3 in the clutch line and reservoir I need to undue the clutch slave cylinder bleeder screw. Unfortunately, I probably over tightened the thing in the summer of 2018 when I put in the new aftermarket slave cylinder. Yesterday, I managed to strip the bleeder screw. I even tried to use a vice grip on the stripped bleeder screw but to no effect. By the way, I did apply rust penetrant to the target area and waited for 10 minutes but that didn't do the trick. The housing of this slave cylinder is very rusted up from the outside (carbon steel casting). I now wish I had bought an OEM salve cylinder back in 2018 because I think those are made of aluminum, thus I would not be having the problem now with a stuck bleeder screw.

It's interesting to note that even though the clutch DOT3 was completely bleed in the summer of 2018 it's black colored right now and this is the only reason I want to bleed it. I do not understand what would cause the DOT3 to look so visibly black after only about 2 years of service. The black appearance it evident when looking into the reservoir.

Seems like my only choice now would be to leave it as is since everything works fine, except the fluid is black, or buy and install a new slave cylinder just so that I can bleed it and that's a lot of work I don't wish upon myself.

Thinking some more, maybe the black contamination of the clutch DOT3 comes from the black colored hose that I put in back in 2018 to connect the clutch reservoir to the clutch master cylinder? If this is the case then I wonder if this is doing any harm?

 

Clutch fluid can turn black in as little as rwo weeks. It gets pumped much more often than brake fluid, and changes color much sooner. I wouldn't think the hose would change the color, that would seem to me it was deteriorating if that happened. I would leave it alone if it was me at this point.