Air in clutch lines/hydraulics?

[bsn]

The silicone grease on a new unit is only to protect the seal from dry operations, once its filled with brake fluid the brake fluid is the lubricant and the only lubricant needed.

[J35Y2]

Originally Posted by bsn

The silicone grease on a new unit is only to protect the seal from dry operations, once its filled with brake fluid the brake fluid is the lubricant and the only lubricant needed.

That's what I was thinking as well. I mean, the way the lubricant made it's way into the CMC, isn't that normal? It also seemed like that was the only other thing that could've made the seals inside fail as well, so I'm not even sure anymore.

The main plunger shaft that was also lubricated with the same silicone stuff, seemed to move like crap once I had it on the car long enough, for it to dry out. The hydraulic pressure was enough to push it back to return, as well as me pushing on the pedal to move the plunger shaft; it just simply felt like crap when taken off of the car.

This is why I was concerned with adding extra silicone lubricant on my most recent CMC that I installed. As for all of the other previous failed ones, I never touched them and they still failed, so I was thinking it was related to maybe a particular part number that was defective. I updated my Amazon reviews, but am not sure if the AC Delco CMC that I had issues with (with the opaque colored plunger attachment), posted it on their listing yet.

[J35Y2]

So… if my new clutch master cylinder hasn’t failed, and my clutch pedal keeps getting softer and softer after a few weeks of driving… I can only think that maybe my bone stock clutch slave cylinder might be faulty..? The CSC is the bone stock, original one from the assembly line, and I haven’t touched anything else on the hydraulic clutch system, besides the numerous failed CMC’s, and the upgraded stainless steel braided clutch line and Pontiac GTO remote clutch master cylinder fluid reservoir.

I sometimes bleed the CSC again after a few days or so of driving, after it’s “broken in” (most people probably won’t bother), just out of my paranoia and experience with my current clutch hydraulic issues… It will feel like a brand new car, with a super hard pedal, where engaging all the gears with the shifter actually feels like a brand new car. And then after driving for a few weeks, the clutch pedal gradually gets softer, and you can tell either air has gotten in, and the shifting quality has decreased, probably because the clutch isn’t disengaging 100% from the lack of full clutch hydraulic pressure…

I mentioned before how I would always bleed the clutch, have a perfectly functioning transmission, and then end up with a notchy, sloppy feeling gearbox within weeks to months of bleeding the clutch slave cylinder… At this point, I think replacing the clutch slave is the only other thing I can do, so I don’t constantly change my transmission fluid early (been seeing more metal shavings than typical manual transmission servicing).

I hate how the clutch assist spring gives the clutch pedal extra pressure, as kind of a “fake” hard clutch pedal feel. If you take the spring out, it feels like one of the most basic clutch pedals. I rigged up my own return spring since I didn’t wanna pay $90+ for the Lingenfelter one, and with what has been going on, I didn’t feel safe enough to let the clutch pedal function all by itself, with no return/assist clutch pedal spring. Even with the return spring in place now, you can press it a little and notice not actual dead pedal, but a much softer pedal and lack of hydraulic pressure, all the way through the clutch pedal’s travel.