Bleeding a new master

[Rock]

I am trying to bleed my new master and it seems I am having trouble getting all the air out. I have it attached to the booster and I am bleeding the fluid back into the master. I know they say bench bleed but I already had it attached to the booster. If it needs to be level than I can remove it. Is it necassary to. E level when bleeding?

[cny first gen 71]

Yes it needs to be level. Pull it back off and do it in a vice.

[Rock]

One more question. Is it easier to bleed the whole system using a vacuum pump? The kit is only $50. Is it worth buying?

[dejh22]

I just put new brake lines and porpotioning valve on my 71. The master cylinder and the whole system was bone dry. I filled the master and had a helper pump the brakes 5 times and hold it. I opened the bleeder starting on the right rear. I would close the bleeder and tell my helper to let up on the pedal. Then pump 5 more times and repeat. I did this until I got a straight stream of brake fluid. Then I moved on to the left rear, then the right front and then the left front. I would make sure the master stayed full of fluid. The brake pedal is firm, brakes work good. I did not bench bleed the master. Had I bench bled the master I would of save some fluid.

 

Dale

[dejh22]

One more question. Is it easier to bleed the whole system using a vacuum pump? The kit is only $50. Is it worth buying?

 

I did buy this but did not use it. I bought it just incase I had issues bleeding the system. I happy to say I did not.

 

http://www.ebay.com/itm/231887233843?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

 

Dale

[Rock]

I will bleed the master a little better. Then just use the pump the pedal method to bleed the brakes. I have done this before just never with a new master.

[dejh22]

I will bleed the master a little better. Then just use the pump the pedal method to bleed the brakes. I have done this before just never with a new master.

I have done it many times with a new master. Never bench bled. Maybe if I had, it would of been easier.

 

Dale

[Rock]

I did buy this but did not use it. I bought it just incase I had issues bleeding the system. I happy to say I did not.

 

http://www.ebay.com/itm/231887233843?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

 

Dale

I know some have had problems trying to bleed and found these pumps save a lot of time and hassle and some don't. I have all winter. I will see if I can get away without the added expense.

[dejh22]

Good luck. Just make sure you keep the master full of fluid. Which I'm sure you already know.  

[MCfan]

Glen, for what it's worth, my photo journal on replacing a master cylinder includes several slides on bench-bleeding the master cylinder and bleeding the brake lines and wheel cylinders.  Here's the LINK.

 

I held the master cylinder level in a simple temporary fixture clamped in my bench vise while I used an  assortment of small parts I had on hand (didn't have to buy anything special).  As usual, I improvised to make a simple tool to manually pump the cylinder to bleed all of the air bubbles out.  There are probably easier, quicker or more sophisticated ways to do this, but I can tell you it was infinitely better than trying to fill and bleed the master cylinder while on the car (I actually did that once - which was enough).

 

One important thing to remember when you bleed the brake lines is to block the proportioning valve open by holding the little plunger (on the back side) in with a wedge of some kind (I used a couple of wooden door shims).  Good luck.

 

PS Hope Lucy is continuing to improve since returning home from Mexico - please give her my best wishes.

[Rock]

Glen, for what it's worth, my photo journal on replacing a master cylinder includes several slides on bench-bleeding the master cylinder and bleeding the brake lines and wheel cylinders.  Here's the LINK.

 

I held the master cylinder level in a simple temporary fixture clamped in my bench vise while I used an  assortment of small parts I had on hand (didn't have to buy anything special).  As usual, I improvised to make a simple tool to manually pump the cylinder to bleed all of the air bubbles out.  There are probably easier, quicker or more sophisticated ways to do this, but I can tell you it was infinitely better than trying to fill and bleed the master cylinder while on the car (I actually did that once - which was enough).

 

One important thing to remember when you bleed the brake lines is to block the proportioning valve open by holding the little plunger (on the back side) in with a wedge of some kind (I used a couple of wooden door shims).  Good luck.

 

PS Hope Lucy is continuing to improve since returning home from Mexico - please give her my best wishes.

There is another valve attached to the frame below the booster. Does that have a plunger on it also?

[lastss]

I let it gravity bleed to fill most of the system to r rear then forward. If you want the best firm petal.? Take a large plastic syringe & draw the fluid out. Did on the race cars worked awesome.

[MCfan]

There is another valve attached to the frame below the booster. Does that have a plunger on it also?

 

I think I know the one you are speaking of, Glen, but I'm pretty sure that is just a manifold block and not a valve.  In any case, I did not have to mess with it to do any system bleeding.

[dejh22]

There is another valve attached to the frame below the booster. Does that have a plunger on it also?

I think what you are asking about is the proportioning  valve.

 

http://www.getdiscbrakes.com/knowledge-base/GM_Classic_Car_Valve_Configurations

[Rock]

Pretty sure I have the master bled, now I need to find an assistant to get the air out of the lines.

[71 MONTE 4 YA]

Pretty sure I have the master bled, now I need to find an assistant to get the air out of the lines.

Glen when I'm working by myself I usually get a long bar or something and pump the brakes up and use the bar against the front of the seat and on the brake pedal. It takes awhile but the job gets done.

[dejh22]

Pretty sure I have the master bled, now I need to find an assistant to get the air out of the lines.

If you were in my zip code. I would give you a hand!  lol

[Rock]

If you were in my zip code. I would give you a hand!  lol

you have around 6 months before the car sees day light

[bigtankjones]

I have always bench bled my master cylinders in the vice. You can always do a gravity bleed.

[Rock]

I have always bench bled my master cylinders in the vice. You can always do a gravity bleed.

I pulled it back off and bled it in a vice. Pretty sure the master is good but there is massive air in the lines. I think I will start a gravity bleed tonight. Should I do one line at a time or should I do both rears at the same time?

[dejh22]

I pulled it back off and bled it in a vice. Pretty sure the master is good but there is massive air in the lines. I think I will start a gravity bleed tonight. Should I do one line at a time or should I do both rears at the same time?

I tried to gravity bleed mine. I opened all the bleeders. It sat all day and nothing! It might of been because I did not bleed the master? From what I have read you open all bleeders and wait and wait a long time. 

[lastss]

One at a time, after the first one it goes quick. need to leave the lid off master. Don't walk away stay & watch & attch a tube into a bottle. RR LR RF LF your done.

[TAG429]

Gravity bleeding did not work for me.  I used a Pneumatic Brake Fluid Bleeder (this one: http://www.harborfreight.com/brake-fluid-bleeder-92924.html) to get fluid flowing to the calipers.  I would run the fluid down in the master (but not dry) 2 or three times which pretty much removed the air.  I would then ask my lovely wife to pump the brakes to finish with a pressure bleed.  

[TAG429]

A good practice to ensure you have a good master is to plug the ports to ensure you have no air in the system after bench bleeding with the tubes.  Mount the master to the booster with the plugs still in the ports and press the brake pedal and hold for 30 seconds.  The pedal should be firm and no movement the entire length of time.  

 

I just recently did the above mentioned steps and still had a bad NEW master cylinder.  The new master bench bled fine and held pressure when plugged off and on the car.  I connected the lines to start the line bleeding and it would only spurt minimal amount of brake fluid.  In the end the New master had bad internal seals therefore pushed more air then fluid.  I had to return and get another new master which solved that problem.

[Rock]

A good practice to ensure you have a good master is to plug the ports to ensure you have no air in the system after bench bleeding with the tubes.  Mount the master to the booster with the plugs still in the ports and press the brake pedal and hold for 30 seconds.  The pedal should be firm and no movement the entire length of time.  

 

I just recently did the above mentioned steps and still had a bad NEW master cylinder.  The new master bench bled fine and held pressure when plugged off and on the car.  I connected the lines to start the line bleeding and it would only spurt minimal amount of brake fluid.  In the end the New master had bad internal seals therefore pushed more air then fluid.  I had to return and get another new master which solved that problem.

I read your nightmare when I did a search. My luck I will have the same problem. Nothing seems to go smoothly for me.