And this must be done off the car so that the m/c is level. 
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bleeding brakes - need quick help
Thread Starter
Racer
Joined: Apr 2007
Posts: 357
Likes: 0
From: Porters Lake Nova Scotia
bleeding brakes - need quick help
im attempting to bleed my brakes this afternoon and im having troubles. The front 2 are bleeding fine, but the back 2 are not. When i pump the pedal there are some bubbles that come out, and then when i let go of the pedal it suck the fluid back up into the line. Probem is that the fluid on the master cylinder isnt going down at all. Im not dripping any fluid on the floor either, and there is fluid is rear line port at the main block. What does this mean?
Race Director
Joined: Jul 2004
Posts: 12,696
Likes: 329
From: Scottsdale Arizona
Are you closing the bleeders between braking cycles? You can only do without if you're using speed bleeders.
You need two people to do the job with regular bleeder screws. Have someone behind the wheel that listens. Tell him/her to press the brake pedal. Open the screw. Close the screw. tell the person to let the pedal back up. Repeat until no more bubbles.
Also remember the order in the back. Drivers inner, drivers outer, passenger inner, passenger outer.
You need two people to do the job with regular bleeder screws. Have someone behind the wheel that listens. Tell him/her to press the brake pedal. Open the screw. Close the screw. tell the person to let the pedal back up. Repeat until no more bubbles.
Also remember the order in the back. Drivers inner, drivers outer, passenger inner, passenger outer.
Team Owner
Joined: Aug 2006
Posts: 24,125
Likes: 15
From: Columbia Missouri
It means you're not bleeding right. To properly do it without check valve bleeders, you need two people. Someone manning the pedal to pump and HOLD when it's firm, and someone to release the pressurized fluid and quickly close it again before the pedal is released.
If you have check valve bleeders, you can do it by yourself because the check ***** keep air from getting sucked in and the fluid can only escape when under pressure.
If you have check valve bleeders, you can do it by yourself because the check ***** keep air from getting sucked in and the fluid can only escape when under pressure.
Le Mans Master
Joined: Apr 2005
Posts: 6,349
Likes: 419
From: Seattle Area WA
Also when bleeding the rears, bleed the inside portion of the caliper first, then the outer half of the caliper to get all the air out.
Is this a new master cylinder too, if so, did you bench bleed it first?
Is this a new master cylinder too, if so, did you bench bleed it first?
Race Director
Joined: Sep 2001
Posts: 10,560
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From: Wellington, FL
St. Jude Donor '11 thru '25
Thread Starter
Racer
Joined: Apr 2007
Posts: 357
Likes: 0
From: Porters Lake Nova Scotia
alright, yes it is a new mc, and yes i did bench bleed it, off the car. I have pwr brakes if it matters or not.i got a buddy, i opened the valve, he pushed the pedal down and held, i closed the valve, and he let the pedal up. The bubbled came out for about 3 times then they stopped coming, but i could see the air in the lines. As he would push down, i could see the air coming down the tube and as it was about to go into the jar, my buddy ran out of pedal room. Am i still doing this improperly.
Team Owner
Joined: Aug 2006
Posts: 24,125
Likes: 15
From: Columbia Missouri
Standard bleeding 101:
With the bleeder valve CLOSED, have someone press pedal repeatedly until pedal becomes hard, and have them HOLD IT IN while hard applying constant pressure on the pedal. While that person is holding the pedal, release the pressure from the bleed valve and QUICKLY close it again.
Do this, PER CALIPER, five to ten times, starting with the rear circuit and the furthest caliper from the master.
With the bleeder valve CLOSED, have someone press pedal repeatedly until pedal becomes hard, and have them HOLD IT IN while hard applying constant pressure on the pedal. While that person is holding the pedal, release the pressure from the bleed valve and QUICKLY close it again.
Do this, PER CALIPER, five to ten times, starting with the rear circuit and the furthest caliper from the master.
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Advanced
Joined: Dec 2006
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From: mobile alabama
anybody ever try gravity bleeding? aftre several attemps to bleed my new calipers my son a tech at the mercedes just filled the m/c and opend the rear bleeder screws and let them drip for several hours. added some fluid to the m/c and then it only took 5 minutes to bleed the system by pumping. ya better wear your seatbelts or you are going thru the window.
Team Owner
Joined: Aug 2006
Posts: 24,125
Likes: 15
From: Columbia Missouri
anybody ever try gravity bleeding? aftre several attemps to bleed my new calipers my son a tech at the mercedes just filled the m/c and opend the rear bleeder screws and let them drip for several hours. added some fluid to the m/c and then it only took 5 minutes to bleed the system by pumping. ya better wear your seatbelts or you are going thru the window.
Gravity bleeding is hit and miss in Corvettes. Air bubbles high in the rear system and in the calipers can cause problems.
Race Director
Joined: Sep 2001
Posts: 10,560
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From: Wellington, FL
St. Jude Donor '11 thru '25
anybody ever try gravity bleeding? aftre several attemps to bleed my new calipers my son a tech at the mercedes just filled the m/c and opend the rear bleeder screws and let them drip for several hours. added some fluid to the m/c and then it only took 5 minutes to bleed the system by pumping. ya better wear your seatbelts or you are going thru the window.
Race Director
Joined: Sep 2001
Posts: 10,560
Likes: 439
From: Wellington, FL
St. Jude Donor '11 thru '25
Race Director
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From: Duvall, WA
Team Owner
Joined: Jul 2001
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From: Here to make friends
St. Jude Donor '11, '16-'17
The bold part is your problem. Before the pedal is released, you MUST close the bleeder valve.
Le Mans Master
Joined: Apr 2005
Posts: 6,349
Likes: 419
From: Seattle Area WA
Hi Jud,
I have the Pro model which comes with adapters that cover most of the cars I have. I use Denatured Alcohol to clean it out. A large C clamp is the best method to hold the Chevy adapter in place rather than the goofy chains they supply.
I have the Pro model which comes with adapters that cover most of the cars I have. I use Denatured Alcohol to clean it out. A large C clamp is the best method to hold the Chevy adapter in place rather than the goofy chains they supply.
Thread Starter
Racer
Joined: Apr 2007
Posts: 357
Likes: 0
From: Porters Lake Nova Scotia
Update
I tried to take another try at bleeding the brakes again tonight. I had the m/c cap on, all bleeders closed. My buddy started pumping the pedal for about 5 mins, and the lines didnt go hard. So we tried it the way where you depress the pedal open and close the bleeders, then let the pedal up. This was, there was some bubbles coming out, but the m/c fluid didnt go down at all, and we were bleeding for about 5-7 mins. Any help
