99 Saturn SC2

I was bleeding my brakes and accidentally let some air into the master cylinder because I didn't refill the reservoir. I was going to take the master cylinder out and bench bleed it but the first nut that I tried taking off began to strip. I didn't try moving it much and went and bought some flange nut wrenches to see if they'd do the trick. Sure enough it didn't work. I decided to try using a vacuum on the reservoir to get the air out. I was slowly increasing the pressure and it actually seemed to be working. Until I believe I may have put too much pressure on it and ruined the master cylinder. I brought it up to about 25inHg (12-13 psi) and after that my brake pedal would go all the way to the bottom. I was really confused as to why this was happening and thought that maybe I had sucked up some air from the line that had gotten air into it, so I decided to bleed it. This helped a bit with the pressure, the brake is a bit more stuff but it is still going all the way to the bottom. I also notice that after pumping it it'll get more stiff then when the brake is released some brake fluid will shoot up in the reservoir(not a lot), it's similar to when air bubbles come up in the reservoir but I know it's just liquid since they're are no bubbles and I just see the surface move around a bit.

Thanks for any help! This is quite frustrating as I'm not sure how I'll replace the master cylinder with the but starting to strip. Any suggestions about max psi of vacuum on the reservoir in the future?

https://youtu.be/dQ5yntvc5C0 This is the video I was following although I was doing it in the car, I should have looked at the pressure that he used.

  • 1
    No, that would not ruin the MC. Start over and bench bleed the MC, install and bleed the system, do not let the fluid get low this time.
    – Moab
    Aug 26 '16 at 21:20

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