Bench Bleeding - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

decco · 12-05-2008, 09:16 AM

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*** · 12-05-2008, 09:44 AM

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 · 12-05-2008, 10:39 AM

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 · 12-05-2008, 10:43 AM

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 · 12-05-2008, 11:09 AM

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

s13Carlo · 12-05-2008, 04:49 PM

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 · 12-06-2008, 04:27 PM

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 · 12-06-2008, 05:09 PM

Quote:

Originally Posted by 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

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 · 12-06-2008, 05:36 PM

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 · 12-07-2008, 07:44 AM

Quote:

Originally Posted by 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.

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 · 12-07-2008, 09:01 AM

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!

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 · 12-07-2008, 09:05 AM

Quote:

Originally Posted by 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!

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:

12-05-2008, 09:16 AM	#1
decco Join Date: Feb 2007 Location: Richardson Age: 37 Posts: 42 Trader Rating: (1) Feedback Score: 1 reviews	Bench Bleeding 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?

12-05-2008, 09:44 AM	#2
*S14DB* AFC #1 Join Date: Oct 2003 Location: 昨晩あなたのお母さんの家 Posts: 20,181 Trader Rating: (3) Feedback Score: 3 reviews	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. __________________ Comments should be taken as Opinions not as Statements of Fact

12-05-2008, 10:39 AM	#3
Propaganda Zilvia Junkie Join Date: May 2005 Location: Charleston, SC Age: 38 Posts: 451 Trader Rating: (10) Feedback Score: 10 reviews	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.

12-05-2008, 10:43 AM	#4
racepar1 Post Whore! Join Date: Jul 2007 Location: Simi Valley, CA Age: 42 Posts: 9,006 Trader Rating: (106) Rides Gallery: racepar1 Feedback Score: 106 reviews	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.

12-05-2008, 11:09 AM	#5
decco Join Date: Feb 2007 Location: Richardson Age: 37 Posts: 42 Trader Rating: (1) Feedback Score: 1 reviews	Thank you for the input. I'll try it out later tonight when I get home.

12-05-2008, 04:49 PM	#6
s13Carlo Leaky Injector Join Date: Feb 2008 Location: 805 Posts: 105 Trader Rating: (0) Feedback Score: 0 reviews	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

12-06-2008, 04:27 PM	#7
Def Post Whore! Join Date: Apr 2004 Location: Houston, TX Posts: 2,701 Trader Rating: (16) Feedback Score: 16 reviews	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.

12-07-2008, 09:01 AM	#11
justaKAiswear Zilvia Member Join Date: Feb 2007 Location: FLA Age: 40 Posts: 194 Trader Rating: (1) Feedback Score: 1 reviews	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! 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.