Master cylinder bleeding trick
Thread Starter
Safety Car
Joined: Jan 2004
Posts: 3,759
Likes: 8
Master cylinder bleeding trick
Has anyone performed the master cylinder bleeding trick as outlined in the 101 Corvette projects book?
It says after you have bench bled the master and bolt it down to the booster and hooked up the lines. That you loosen one of the master cylinder line fittings so that a little fluid leaks out. Then have someone push the pedal to the floor. Tighten line. Release pedal. Then do the other line. And then do both lines again a couple more times.
That is so you don't have to flush/bleed the lines at the calipers. Just wondering if that would work? I normally would take that opportunity to flush the fluid. But if you've already flushed it, then had to replace the master. Would be nice to not have to flush it again.
It says after you have bench bled the master and bolt it down to the booster and hooked up the lines. That you loosen one of the master cylinder line fittings so that a little fluid leaks out. Then have someone push the pedal to the floor. Tighten line. Release pedal. Then do the other line. And then do both lines again a couple more times.
That is so you don't have to flush/bleed the lines at the calipers. Just wondering if that would work? I normally would take that opportunity to flush the fluid. But if you've already flushed it, then had to replace the master. Would be nice to not have to flush it again.
Drifting
Joined: Aug 2006
Posts: 1,624
Likes: 2
From: Canandaigua New York
You can actually do both of them at the same time.
If your lines are still fairly full, then just have someone push the pedal down just enough so the fluid 'leaks' out of the lines and then tighten. You don't need to push the pedal to the floor.
If your lines are still fairly full, then just have someone push the pedal down just enough so the fluid 'leaks' out of the lines and then tighten. You don't need to push the pedal to the floor.
Le Mans Master
Joined: May 2006
Posts: 9,226
Likes: 9
From: Irvine Ca
My experience has proven that all these tricks etc. are the result of folks not properly understanding the hydraulics
have a friend sit in the car.....start on the Right Rear caliper.
put a clear plastic tube that fits the bleeder valve onto the bleeder and run the other end down into a clear coke bottle. Miller Genuine draft bottle will work as well.
(Loosen the bleeder valve) Pump, hold (tighten the bleeder valve) release.
if you are smart you'll tighten the bleeder valve just before your friend, GF, Wife, 5 year old son reaches the end of the brake pedal stroke
Repeat this until you see and hear the air bubbles (after the fluid turns clear) come out. You'll see/hear them as they escape the barely open bleeder valve.
Work up some spit in your mouth......now force that spit between your teeth....that the sound the last bit of air bubbles will make when they run through the bleeder valve....turn the Led Zeppelin down so you can hear it.
Now take all the bench bleeding time wasting "tips" and use them for toilet paper.
have a friend sit in the car.....start on the Right Rear caliper.
put a clear plastic tube that fits the bleeder valve onto the bleeder and run the other end down into a clear coke bottle. Miller Genuine draft bottle will work as well.
(Loosen the bleeder valve) Pump, hold (tighten the bleeder valve) release.
if you are smart you'll tighten the bleeder valve just before your friend, GF, Wife, 5 year old son reaches the end of the brake pedal stroke
Repeat this until you see and hear the air bubbles (after the fluid turns clear) come out. You'll see/hear them as they escape the barely open bleeder valve.
Work up some spit in your mouth......now force that spit between your teeth....that the sound the last bit of air bubbles will make when they run through the bleeder valve....turn the Led Zeppelin down so you can hear it.
Now take all the bench bleeding time wasting "tips" and use them for toilet paper.
Racer
Joined: Sep 2009
Posts: 414
Likes: 0
From: Oxford CT
I made one of these and was able to flush my entire system in about under an hour, including the MC. Once it's connected just pump up the tank, open the bleeder screws in order, crack open a cold one, and then watch the magic.
I think it cost me about 40 bucks including the fluid and 12lbs of pressure was all I needed. Plus, you can use it to tackle the master and slave clutch cylinders (if you have a stick car).
I think it cost me about 40 bucks including the fluid and 12lbs of pressure was all I needed. Plus, you can use it to tackle the master and slave clutch cylinders (if you have a stick car).
Thread Starter
Safety Car
Joined: Jan 2004
Posts: 3,759
Likes: 8
My experience has proven that all these tricks etc. are the result of folks not properly understanding the hydraulics
have a friend sit in the car.....start on the Right Rear caliper.
put a clear plastic tube that fits the bleeder valve onto the bleeder and run the other end down into a clear coke bottle. Miller Genuine draft bottle will work as well.
(Loosen the bleeder valve) Pump, hold (tighten the bleeder valve) release.
if you are smart you'll tighten the bleeder valve just before your friend, GF, Wife, 5 year old son reaches the end of the brake pedal stroke
Repeat this until you see and hear the air bubbles (after the fluid turns clear) come out. You'll see/hear them as they escape the barely open bleeder valve.
Work up some spit in your mouth......now force that spit between your teeth....that the sound the last bit of air bubbles will make when they run through the bleeder valve....turn the Led Zeppelin down so you can hear it.
Now take all the bench bleeding time wasting "tips" and use them for toilet paper.
have a friend sit in the car.....start on the Right Rear caliper.
put a clear plastic tube that fits the bleeder valve onto the bleeder and run the other end down into a clear coke bottle. Miller Genuine draft bottle will work as well.
(Loosen the bleeder valve) Pump, hold (tighten the bleeder valve) release.
if you are smart you'll tighten the bleeder valve just before your friend, GF, Wife, 5 year old son reaches the end of the brake pedal stroke
Repeat this until you see and hear the air bubbles (after the fluid turns clear) come out. You'll see/hear them as they escape the barely open bleeder valve.
Work up some spit in your mouth......now force that spit between your teeth....that the sound the last bit of air bubbles will make when they run through the bleeder valve....turn the Led Zeppelin down so you can hear it.
Now take all the bench bleeding time wasting "tips" and use them for toilet paper.
I flushed it not long ago. Then found I had to replace the rotors and pads. So, after cracking the bleeder open to push the piston back, I decided to go ahead and flush it again while I was there.
Not long after that I figure the MC needed replacing, and then read in that 101 project book about the trick on bleeding the master and not having to go to all the calipers. As I figure it would be nice not having to flush the fluid again in such a short time.
Thread Starter
Safety Car
Joined: Jan 2004
Posts: 3,759
Likes: 8
I went ahead and bought new reservoirs. They are only $5 each. As I'll have to put the reservoirs on the rebuilt Master. So, that would save me from having to pull the old reservoirs, and hoping I don't run into a snag installing them as the car wouldn't be driveable with missing reservoirs. I see the service manual says to use a 26 OD and 22 ID pipe to place inside the reservoir when you install it.
Drifting
Joined: Aug 2006
Posts: 1,624
Likes: 2
From: Canandaigua New York
Do you have the lines off the master when you have someone push the brake pedal? Or do you tighten the lines down, then back them off till they start leaking then have someone push the pedal?
I went ahead and bought new reservoirs. They are only $5 each. As I'll have to put the reservoirs on the rebuilt Master. So, that would save me from having to pull the old reservoirs, and hoping I don't run into a snag installing them as the car wouldn't be driveable with missing reservoirs. I see the service manual says to use a 26 OD and 22 ID pipe to place inside the reservoir when you install it.
I went ahead and bought new reservoirs. They are only $5 each. As I'll have to put the reservoirs on the rebuilt Master. So, that would save me from having to pull the old reservoirs, and hoping I don't run into a snag installing them as the car wouldn't be driveable with missing reservoirs. I see the service manual says to use a 26 OD and 22 ID pipe to place inside the reservoir when you install it.
It really doesn't take much pedal travel before the fluid starts to flow.
I usually make sure there is fluid in the lines before I bleed the Master cylinder to avoid trapped air.
I know there are some that don't like this method. But it has worked pretty well for me in the past with no problems.
Last edited by Keystring; Sep 11, 2010 at 07:34 AM.
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Thread Starter
Safety Car
Joined: Jan 2004
Posts: 3,759
Likes: 8
Connect the lines snuggly. Have someone push the pedal slowly and then loosen the lines just enough until fluid starts to come out. Tighten them back up before the pedal reaches the floor. You can do it a couple of times if you want to be sure.
It really doesn't take much pedal travel before the fluid starts to flow.
I usually make sure there is fluid in the lines before I bleed the Master cylinder to avoid trapped air.
I know there are some that don't like this method. But it has worked pretty well for me in the past with no problems.
It really doesn't take much pedal travel before the fluid starts to flow.
I usually make sure there is fluid in the lines before I bleed the Master cylinder to avoid trapped air.
I know there are some that don't like this method. But it has worked pretty well for me in the past with no problems.
