The Stovebolt Site Forums The Shop Area Engine Shop Breaks

Bench bleeding the Master Cylinder is always a good idea.

How do you do it?

Holding the mastercylinder level, say in a vise, run hoses from the outputs back into the resevoirs. Then using a rod/stick/broom handle, depress the cylinder. This will force fluid into the spaces inside the mastercylinder 'valve/pump'. At first, bubbles will flow from the outlets (where your brake lines or lines to the proportioning valve are usually attached) into the resevoir.

Eventually, the bubbles will stop showing and all you'll see is fluid when you pump the master cylinder. once it is bench bled it is ready to go in. Be careful to keep it as level as possible until you bolt it in lest more air finds its way into the cylinder/valve.

When I bought my master cylinder it came with a kit containing plastic fittings that attach to hoses to put into the outlets of the mastercylinder. Those kits (bench bleeding kits) with the fittings and some pieces of hose are available at places like NAPA.

Best of luck!