Dual Master Cylinder Bench Bleeding

[geordie]

I have a new dual brake master cylinder which I got from the PO when I bought the car about 5 years ago.
It came with a small bag with two threaded plastic male plugs, different sizes, and two plastic female plugs.
The bench bleeding instructions say to clamp the cylinder on a bench, install the bleeder plugs, half fill the reservoir, put the reservoir cover on and pump the plunger in .75 to 1.0 inch strokes until resistance is met.
I'm more familiar with the old tube method of bench bleeding. Is the method described above going to work?

 

[Tim65GT]

geordie
I'm more familiar with the old tube method of bench bleeding. Is the method described above going to work?

I've only done it with the tubes fed back into the reservoirs also. With plugs in there, you'd think that some air would not make it out.

Either way, when you remove the plugs or tubes, air goes into the port openings

Once you feel resistance, i guess that means the air is out and the fluid is in.

 

[Rusty67]

I've done it this way and it works perfectly fine. I actually like it better except the fact that it is messy. Put a rag or a catch pan under the MC. You can actually do this in the car if you install the MC and jack the rear of the car so that the MC sits at a proper level for bleeding but again, with the mess its better to do this out of the car.

 

[geordie]

Why so messy?
Both ports are plugged and the cover is on the reservoir.
Does the fluid squirt out of the plastic plugs under pressure?

 

[wild70stang]

When I bench bled my new master cylinder it didnt leak, so not its not messy unless you dont tighten the pluggs and wave around the MC with the cover off. Also when pushing in the plunger, do this procedure while slightly tilting the MC up and down to get any remaining air bubbles out that might be caught.

 

[Rusty67]

I've done 3 MC's this way. They have all leaked passed the plastic threads. I was only willing to tighten the plastic so much but I'm sure if it had been a brake line fiting it would not have leaked on me. Also, you have to remove the plugs. When you remove the plugs there is going to be some fluid to deal with.