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Do you have to bench bleed the master cylinder or not??
I bought a Hastings master cylinder earlier this year for my 78 resto. At some time I removed the shipping plugs and threw them away.
I go to install it now and the instructions state... Remove the plugs and wait for fluid to start to drip out and reinstall the plugs. Take a bleeding tool and start to stroke the piston in 1" strokes. Continue until it will move only 1/8th of a inch and no air bubbles are visable in the reservoir.
I am still in the middle of the restoration and the vette is up on jacks and all the brake system is new..lines,calipers and all. So I go ahead and install the master cylinder and hook up the lines and gravity bleed the sytem. When I first fill up the master cylinder I get air bubbles coming up from the holes in the bottom. I let them play out and then start to pump the pedal some. Seeing how the calipers are all closed the system is basiscally close up like the plugs are in it is my guess. I then pop open a bleeder screw and start to gravity bleed the system using a baseball bat to pump the pedal to get things going until I have no air coming out of the tube in the jar at each caliper.
The pedal is pretty firm and has very very little travel. The motor has not been started to bring the power booster into play yet and will be a week or so out before I can do that due to dropping the headers to modify my rocker panels for the Hooker sidepipes.
Question is...Am I going to have to bench bleed my master cylinder anyway or on the vehicle with tubes or may I not have to do anything else??
Any and all suggestions and comments are welcome...
It was my first time gravity bleeding a vehicle and it was pretty simple and cool to do.
Neil in Tenn
Re: Do you have to bench bleed the master cylinder or not?? (Nomad78SA)
I just bench bled a new M/C last night. I have one of those syringes called an EZE Bleeder that you use to push fluid into the M/C. After that I used some steel line bent into each reservoir and slowly pushe din the piston. I still ahd small bubbles from the smallest bottom hole so I continued only switched to a long brass rod for leverage. It took longer then expected this time but the piston finally became difficult to push in. I installed it and let the fluid weep out a second then installed the lines. I didn't get a chance to bleed the system yet because we got yet another rain filled Sunday. If you decide to use the line into the M/C for bleeding then they are metric,not standard fittings. Avoid the plastic M/C bleeder kits in see in the parts stores the fittings don't work- I was sucking air in every time I pushed the piston in.