Diagnosing Brakes/Air Pack Problem??

[JoeM35]

Need help with brake problem.
No brake pedal - goes to floor.
Master Cylinder is empty. Refilled, empty again.
No visible leaks from MC
No visible leaks from Air Pack
No visible leaks from wheel cylinders (no fluid drips on rims/tires)
Air pressure is normal.

MC is red primer color - replacement?

Does this sound like MC or Air Pack problem - or both?
Should I replace Air pack first?
Who is a reputable supplier of new/rebuilt Air-Packs?
I'm not equipped to work on this deuce, so I have to rely on a local truck shop for repairs.
Thanks for any suggestions.

 

[Heavysteven]

So you refilled and it dissappeared? Did you bleed each wheel? My guess is you have a leak or you have air in the system. Either way brake fuild does not vanish.

 

[bigmike]

agreed with Heavysteven.

I'd do a power bleed and open up the farthest rear tire and keep filling until it quits spitting. You'd be surprised how much fluid it takes to fill all the lines.

 

[Castle Bravo]

If that happened to me, I would think that there was no fluid in the lines to begin with and the fluid that you put into the master cylinder that later disappeared went into the lines.

I'm no expert, but I'd say fill the master cylinder until it stays full and then bleed the brakes according to the TM.

 

[LiqTenEXp]

you want to look and see if it's leaking from a wheel cylinder.

I just went through replacing/rebuilding my whole brake system. The fluid goes from MC to the front section of the air pack. From this point it's either getting into the air side of the air pack or coming out of a wheel cylinder. You can pull the J pipe or the allen on the back of the air pack to check for brake fluid.

Keep going till you put in at least 32 oz. I used 48 oz to bled a new MC and airpack.