At the end of the day this is a standard MC and CSC or Slave.
An even more simplistic approach, this is just a hydraulic system.
The reason why folks have a hard time with these:
- The shape of the line tends to trap air
- The clutch softner main culprit (circular piece that attaches to the hard line) all that it is is a chamber that restricts volume by using a restrictor like turbos.
- This chamber does not like debris at all and once debris enters it's really difficult to clean just by fluid exchange.
- Incorrect shaft or pedal lenght
- Lack of bench bleeds
- Deteriorating CSC will make bleeding difficult as well
I recently did a VHR swap on a 350z using 370z pump, CSC and line.
16k mile donor and a brand new CM, had bleeding issues. Little to no fluid coming out of the bleeder. Better flow coming out the CM but not enough.
I deleted the clutch softner and was able to get better flow to the CSC but it barely moved.
In the process of trying to bleed the new CM with the bad line/sofner I killed it. Exchanged the CM for a new one. Bench bled it and installed the cover nipple on the CMC to prevent fluid or air to go into it.
Once installed I set rod length to max and loosened all of my fittings and started pumping. I would get small bubbles as I would pump and once they would disappear I would tighten. Clutch bleeding was a success
Now the next issue was my engagement was about 1/8th of the way from the top and felt like it would work however I would get some stickiness when I would pump all the way.
The issue ended up being that now the rod length needed to be scaled back a few turns and she is golden now.
I took the opportunity of this to make that hardline as straight as possible.
I realized that in all of my MT cars almost all of my clutch hydraulic problems would disappear when I would install a direct braided hose and ditch the softner.