over did it

[brent]

In trying to bleed my brakes I drained the master cylinder. (I started getting lots of bubbles as my first clue). Do I now need to do a bench bleed on the master cylinder to get it right, or can I add more fluid to the thing and bleed all the brakes until the lines are clear of bubbles. If I can do the latter, how much fluid should it need to do the job? This is a 66 dodge Monaco. I'm wondering if the bubbles might be from somewhere else.

 

[Mike66Chryslers]

I've done that a couple times before. You need to bleed the system until all the bubbles come through. I can't tell you how much fluid it will take, but you'll be at it awhile.

 

[forzav12]

When I've done that, I've just cracked the master lines and done a bleed with it on the car, connect them up and bleed the rest. It took an entire quart of fluid before there were no bubbles.

 

[67Monaco]

I usually bench bleed on the vehicle. Just pop down to napa get the appropriate fitted line as short as you can, disconnect one fitting at a time, bend the line so it dumps back in to the reservoir and pump the brakes until there's no more bubbles. Usually very quick.

 

[live4theking]

I usually bench bleed on the vehicle. Just pop down to napa get the appropriate fitted line as short as you can, disconnect one fitting at a time, bend the line so it dumps back in to the reservoir and pump the brakes until there's no more bubbles. Usually very quick.

I'll second this or they make a little kit with plastic lines for doing the same thing. It's a generic kit. I've had one for years.

 

[rags]

When I've done that, I've just cracked the master lines and done a bleed with it on the car, connect them up and bleed the rest. It took an entire quart of fluid before there were no bubbles

i'll second this because this is how professional mechanics bleed masters. crack 'em, push the pedal half way to floor, close 'em, let the pedal up, repeat as necessary.

 

[CBODY67]

OR . . . you can rig something to do it like they do at the assembly plant. Fill the master cylinder and then pull a vacuum on the cylinder reservoir. "Air" comes out, fluid goes in. Making the necessary "board" to seal the cylinder with might be an issue, or just put a fitting in an old reservoir cap/seal?

At the plant, they put a fixture on the master cylinder, pull a vacuum. When it stabilizes (indicates "no leaks"), then the fluid goes in. Same with coolant and possibly power steering fluid.

The times I've changed a master cylinder, I'd fill it after it was on the car, with the lines connected. Then I'd "punch" the brake pedal quickly several times. Enough to compress the fluid. On the "decompress" side of things, "air" usually came out. Not much, though. Not too much unlike how the GM Tech II "bleeds" the system, with everything still hooked up, by cycling the system with pressure/non-pressure pulses, except much faster.

Just some thoughts,
CBODY67

 

[LocuMob]

I bench bleed the master, in the car. Then bleed the system. I get to do this soon going from single to dual circut master, pulling the pedal off the floor gets old. Remember to start at the right rear and go to the next wheel furthest away from the master.