First time I am ever replacing a master cylinder on my 75 malibu. I bought the new one from advanced auto, it is not a rebuild. It is sitting on the bench and is bled for the most part. I put the plastic adapters and rubber hose on to do this. I snugged the plastic adapters, they are leaking a little, but when I pump it slowly there is not air in the lines anymore. The only place I continue to get bubbles that wont go away is in the rear reservoir where when I push the piston in just slightly and let it out a bubble will come out of the rear hole rear res. It wont stop doing this. Is it ready to go onto the car? Also any advice on bleeding some of the old stuff out of the system? I also remember when doing the wheel cylinders when I had the 69 chevelle that I re-cracked the bolts to its master cylinder during the process cause was told air can get trapped there.
Just do your best to get all the air out you can but once you take out the plastic adapters and hook up the hard lines you will most likely get a little air in it. I use a bleeder that creates a suction and start from the rear wheels and work my way to the front. I have noticed that you have to let it sit for a while so all the little air bubbles combine and bleed out properly. Steve
As for that little bit of bubbles still there, i always get that too. Install in car and tighten lines on master. Before bleeding on all 4 corners have someone pump the brake pedal then hold it to the floor. crack open the line going to the master so the fluid seeps out. Do both both lines going to master but one at a time. That usually gets rid of the remaining air. now you can bleed on all 4 corners. Allen
Make sure the tubes are submerged in the reservoirs when pumping the piston. Air will backtrack up the tubes. Keep pumping until no more air bubbles appear. :TU:
OK, was success. Seemed like got rid of little bubbles that wanted to keep coming up through the reservoir. Installed on the car, had wife pump pedal three times and hold it, cracked nut and let air out. Did this twice for front and rear. It is fine. I am taking the malibu to Ocean City next week, so I will bleed the brakes after that. Hopefully next year the Buick will be ready to go. As usual thanks for the help.
i'm southeast of Balt... Mine isn't ready yet.. Where do you take your Buick in Baltimore? Any recomendations on Buick people?
