Bench Bleeding the MC

[bmcgc]

The instructions that came with my new booster/MC:

NEW AND IMPROVED MASTER CYLINDER BECH BLEEDING PROCEDURE

1. Tighten supplied plugs into ports
2. Fill reservoir half way.
3. Install reservoir cap.
4. Slowly press in and release the master cylinder piston (3/4-1in).
5. Repeat this step until piston moverment is firm.


Has anyone ever tried this?

[Greg D]

I always bench bleed mine.
I however mount it in place in the vehicle, attach the fittings & the lines and use the brake pedal to do it.
You aren't trying to shove fluid through the lines with the MC seals starting out dry (yea they won't seal well with just air).
Reduces the pressure til you get the piston bore filled with fluid.
The thing they don't tell you, every time you depress the pedal, give the air bubbles a moment to escape before pumping it again.
Gravity bleeding is the best IMHO anyway.
I sometimes use my vacuum pump too.

[LM14]

Had to change one this fall. Bench bled as you described and bolted in place. Never had to bleed it on the truck, worked great from the get go. Clamp it in a vice, used a big punch. No problems.

SPark

[BigMike]

Yep, two ways to do it.

Either block ports and pump slowly or use return lines to the master. I do mine on the truck. Be careful because some masters will shoot brake fluid like a porn star.

[cwindsor]

LOL Mike....

[Toyz]

I still prefer bottle bleeding just in case I should get the rare contaminated master cylinder.
Paul