PontiacBonnevilleClub.com

I need to replace both master cylinder lines. I've never removed the lines from there on any car, only have done brake hoses, calipers and pressure bleeding. My question is will fluid simply just come out or will air be sucked in? I have something to plug the master so as to not lose too much fluid, just trying to be prepared for whatever. Wondering if its possible nothing will come out or be sucked in unless the pedal is pushed. Can someone straighten me out. Go easy on me. lol

If you keep the pedal depressed you will not continue to lose fluid beyond the initial little spill. You'll still have to do a complete bleed on the system.

Sorry I missed your response. I was unable to get the MC lines on the ABS pump free and the weather was not cooperating. This time I relented and had my mechanic do it at the station. Just so I understand, you would push the pedal until it firms up and hold it down with a stick or something? I was thinking the pedal would sink when you removed the lines from the MC but maybe that would happen only if the car was started?

I actually managed to change the master without holding the brake pedal. Did lose a bit of fluid. Used a bench bleed kit on the master from the local auto parts store. Did a quick bleed full system bleed and was on my way. It was a pretty easy job. A set of line wrenches can be really helpful here. I bought a set for this job.

Ditto on the line wrenches. For as often as you'd use them, the cheap Harbor Freight ones work great. I know because I just bought a set and used them on my 57 Chevy.