My master cylinder blew - so I purchased a new one, bench bled it, installed it and power bled the whole system. My pedal goes to the floor first pump but then gives me brakes on the second and third. I am leaking no fluid at all. I have had all the wheels off to clean and inspect the cylinders and the adjusters are up - any ideas why it still seems like air is in the line somewhere? Is it possible to have gotten a faulty master cylinder??

 

if there's air in the line , the pedal would be spongy, you said its hitting to floor ??

Either the fluid is bypassing the piston in the master cyl... or there's not enough brake fluid in the system ..

And BTW what was the problem, with the old one ...?

 

The old CB master cylinders can be a bugger to get all the air out, because of the design. An air pocket stays under the large cap on the end of it. Raising the front of the vehicle so the cap is no longer the highest point can help. The CV cylinders are easier.
Also, it will help if you back off the brake adjusters as far as they go, getting it all bled, then adjusting the brakes when done.

 

Thanks Tom I think that may be it. I have been thinking somehow the master did not bleed all the air out somehow.

 

I forgot to mention, it might help to locate the circuit with the actual problem.
Clamp off all three flex lines. Ideally with Girling brake line clamps.


Or you can use needle nose mole grips with small diameter steel pipe or heavy duty rubber hose over the jaws to protect the brake hose.


With all three hoses clamped off, check the pedal. If it's rock hard, then the problem isn't in the MC, if it goes down and all, there's air in it, or in a line before the flex lines (check for leaks).
If the pedal is hard, remove one clamp and try again. Any more pedal travel and you have a bad circuit there. Bleed that one until all the air is out. Reattach the clamp and repeat for the other circuits.
Once you've done that, remove all the clamps, readjust the brakes and check.

 

Also, how old are the flex lines? If older than 15 years or so, I'd definitely replace them. As they age they swell inside and when you press the pedal, a lot of the volume is used to get them back to the original ID before the wheel cylinder pistons start to move.

 

Tom, all the lines are fairly new. I had the whose system power bled and that is why I am really leaning towards air is still trapped in the cap of the mc. I will be looking into it today. Thanks for the great help guys and I will keep you updated or yell for more help.

 

BINGO!! Raised the front of the vehicle and slowly bled the mc and now I have great brakes. Air bubble in the mc cap was it. Thank You for a great call and all the input here - much appreciated.