Brakes: do I need to bleed the master cylinder?

[hungt1999]

When exactly do you need to bench bleed the master cylinder?

I recently burst one of my rear brake line and I changed both lines. I did the bleeding for all 4 brakes.

Obviously when I removed the old lines, the fluid level in the reservoir emptied out. The question is did I need to perform the bench bleeding of the master cylinder first before bleeding the other 4 brakes?

As I understand, bench bleeding requires to recirculate the fluid from the 2 output ports of the Master Cylinder back into the fluid reservoir using two temporary tubes. But when you remove the temporary tubes, fluid will be pouring out again right? so back to square one?

[Rip The E Brake]

Remove your old master cylinder before you bench bleed and install the new one. The brake master cylinder of a Toyota Corolla is generally located up against the driver's side firewall, next to the strut tower; this differs slightly between models, so just look for the brake fluid reservoir to find the master cylinder.

Step 2

Set your new Toyota Corolla master cylinder in a bench vise; if you don't have a bench vise, you can use a clamp-on vise and an old table. Clamp the cylinder firmly into place, making sure that it's level. Open up the bench bleed kit and have it close by.

Step 3

Put the old reservoir into the new master cylinder, if you're reusing it. Be sure you clean and dry off the reservoir completely, since brake fluid absorbs water and can damage your brake system. Then, install it into the top of the new master cylinder. If a reservoir came with your new Toyota Corolla master cylinder, you can skip this step.

Step 4

Find the two fittings that came with your bleeder kit. Thread them onto the outlets located on the cylinder; if you're not sure where they are, look on the top and sides of the cylinder for threaded outlet holes.

Step 5

Take the two lengths of hose that came with your kit and insert them into the fittings. Bend the hoses up, so they're aimed into the fluid reservoir.

Step 6

Cut the hoses if necessary so they stick point-down into the reservoir and extend about halfway into it. Use a clip to secure the tubes to the side of the reservoir and keep them in place. You don't want them to come loose and allow air into the system or spray brake fluid around.

Step 7

Fill the Toyota Corolla's reservoir with fresh brake fluid. Pour enough into the reservoir to fill it just shy of the maximum fill line. The plastic hoses will extend down into the fluid, creating a closed hydraulic system.
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Step 8

Pump the piston on the brake master cylinder to move the fluid through the unit and into the hoses. Use a Phillips screwdriver to do this; put the screwdriver into the cylinder and push it firmly against the piston to start pumping.
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Step 9

Watch for air bubbles coming out of the hoses and into the fluid in the reservoir. Keep pumping until all the air is out of the cylinder and you don't see any more bubbles. Consider buying clear hoses if the ones that come with your kit are black, so you can see the air bubbles better.
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Step 10

Leave the two hoses in the reservoir and slowly remove the cylinder from the vise. You can now install the primed master cylinder into your Toyota Corolla.