When installing a new master cylinder, it needs to be bench bled to get all of the air out of the cylinder bore. Most people do this by filling the reservoir with fluid and pumping the pushrod. Some people insert tubes into the ports to direct fluid back into the reservoir, or sometimes they just squirt the fluid into a container. Master Power Brakes has a simpler solution for this process, and it works on the principle that air travels upwards. So instead of pushing the fluid down, they provide you with a syringe that you can use to push the fluid up through the master cylinder bore and into the reservoir.
This process fills the ports with fluid, and when the fluid squirts out of the holes and into the reservoir, the air is pushed out with it. We filled one reservoir about half-way with fluid, then inserted the needle into the fluid to draw it up into the syringe. Then we inserted the needle into the outlet port and squeezed the syringe.
Forcing fluid up through the ports and into the reservoir also pushes the air out of the the piston bore, a quick process that takes little effort.
When the front reservoir was done, we inserted a plug and did the same process to the rear reservoir. Within a matter of minutes, the master cylinder had all of the air bled out of it. We didn’t need to activate the pushrod at all, which can sometimes be a little difficult because it requires a lot of pressure, repeatedly, to get all the air out of the system. Pushing the air up through the cylinder bore is effortless, and takes less time to do. The master cylinder can then be installed on the car with the fluid in the reservoirs, and you can connect your brake lines and bleed your brakes from the furthest wheel cylinder or caliper to the closest.
Be sure to check out the Master Power Brakes web site to see all of their brake performance products, and be sure to contact them for any questions about brake performance or disc brake conversions.