Bench Bleeding

[decco]

I believe I have air in my master cylinder because the pedal is very spongy and the brakes barely work sometimes, and sometimes they just grab and I get a low level warning. I wanted to know, should I be able to perform a bench bleed of the cylinder on the car if I disconnect the brake lines and pump the pedal slowly while keeping the fluid in the reservior above half? After that just connect the lines and bleed each line like normal?

[S14DB]

You have to run lines from the outlets into the reservoir.Then pump the cylinder till all the air is gone.

Is this a new MC that you didn't bench bleed? or is this an old one? If an old one it's probably shot and you need a rebuild. Even if you ran dry you only need to bleed the lines not the MC.

[Propaganda]

I've bench bled a brake master cylinder in my dad's Toyota Previa because after we bench bled the MC, we put it on the car and then let the level go down too low so we had to bench bleed again.

[racepar1]

To bleed the master on the car simply crack the lines open at the master, have a buddy press the pedal down and hold it, tighten the lines, have buddy release the pedal, and repeat 3-5 times. Of course after you bleed the master you still have to re-bleed the wheels as well.

[decco]

Thank you for the input. I'll try it out later tonight when I get home.

[s13Carlo]

you dont have to pull the lines off just loosen the bleed screw, when you loosen it pump the brake a few times, have the pedal stay compressed, tighten the screw, then pump the pedal more until it tightens up again

[Def]

Never repump the brakes while a line or bleeder is open. That's how you get air in the system in the first place.

The procedure is pump the brakes a few times to build up pressure, open a bleeder while keeping pressure on the pedal, then close the bleeder(preferably before bottoming out the MC). Release brakes and repeat.

I've never had to bench bleed a MC. Just toss it up there, fill with fluid and proceed to bleed the car front to back. I like to start at the wheel closest to the MC, but I don't think it matters.

[racepar1]

you dont have to pull the lines off just loosen the bleed screw, when you loosen it pump the brake a few times, have the pedal stay compressed, tighten the screw, then pump the pedal more until it tightens up again


WOW, everybody please disregard the above quoted post. That is just completely wrong in every way other than not have in to pull the lines completely off, which nobody said you had to do in the first place.

[lazysk8er2]

it is very important to bench bleed a MC before installing into a car cuz then you are initially putting air into the system even if you do bleed the lines itll take you so much longer.

[Def]

it is very important to bench bleed a MC before installing into a car cuz then you are initially putting air into the system even if you do bleed the lines itll take you so much longer.

I don't have ABS on my S13, but it took me all of 3 mins to completely bleed the system after replacing the MC without doing any sort of bench bleed on it.

You guys are doing it wrong if you're having major problems with this...


Kind of like how no one here can properly bleed their cooling system with it takes all of 5 mins.

[justaKAiswear]

3 minutes to bleed all 4 brakes and 5 minutes for a cooling system?

Jeez you are awesome! I think you have a future in a pit crew somewhere! :rolleyes:

Racepar1 has thrown out all the info you need to make this happen man, do yourself a favor and buy speedbleeder bleeder valves (NAPA #675-1567, 2 per package) and make your life a lot easier when bleeding brakes.

[Def]

3 minutes to bleed all 4 brakes and 5 minutes for a cooling system?

Jeez you are awesome! I think you have a future in a pit crew somewhere! :rolleyes:

Racepar1 has thrown out all the info you need to make this happen man, do yourself a favor and buy speedbleeder bleeder valves (NAPA #675-1567, 2 per package) and make your life a lot easier when bleeding brakes.

Only an idiot is going to pay NAPA's markup for Speedbleeders. But given your dipshit response, I'm guessing you work there. :ghey: