Deuce brake woes

[M35fan]

I'm having trouble with my 1972 M35A2. It started with a major air leak that wouldn't let air pressure build past 60 psi at idle. I hooked up my shop compressor to the emergency glad hand and found air rushing out through the slobber tube vent. After doing some research I concluded that my air pack needed a rebuild. I ordered the kit from monkeyboyarmy, removed my air pack, and rebuilt it. Now my air pressure builds to 120 psi and holds pressure for at least 24 hours after shutdown.
After the rebuild I had zero brake pedal, which I'm sure is normal as my system needs bleeding. I built a pressure bleeder following recovery4x4's post and purchased all of the DOT 5 fluid I could find here in town. It is painted on the access panel above my master cylinder "Silicone fluid only." The master was slightly low (about an inch from the top) so I began by topping off with new fluid and then attached the pressure bleeder into the master cylinder cap. So far, so good.
I pumped up the sprayer to ~10psi and began by opening the bleeder on the air pack. After a second, yellow fluid came out along with several large air bubbles. I know that the new DOT 5 fluid is purple, so I was confused by seeing the yellow fluid. Have I done the unthinkable and mixed fluid types, or is older DOT 5 yellow also?
I stopped at that point so as not to cause more problems, but if the fluids are mixed I figure the damage is done and now I will have to replace all of my fluid with the purple DOT 5. Any tips or advice on how I should now proceed? I appreciate any suggestions yall may have for this rookie Deuce mechanic.

 

[doghead]

Dot 5 turns yellow with age.

Go back to bleeding....

 

[Recovry4x4]

Agree with Eric, keep bleeding!

 

[M35fan]

Dot 5 turns yellow with age.

Go back to bleeding....

Well, that's a relief. Thank you, sir.

 

[gringeltaube]

In case of doubt just put a bit of your (known) DOT 5 and about as much of the (unknown) fluid coming out of the bleeder, in a clear glass cup. If both portions readily mixed after just stirring a bit you are good to continue.
Try that same with any ethyl-glycol based fluid (like DOT 3 & 4) and adding silicone (DOT 5): your "mix" will promptly separate in two layers, no matter how violently you shake that cup.

 

[M35fan]

Success! I did try mixing the old fluid with the new, it turned a nice plum color and stayed that way. After bleeding I have a good firm brake pedal once again. Thanks to all who put their in. I truly appreciate the help. Now for a nice long test drive.

 

[Recovry4x4]

Excellent news. I can't tell you how many times that $15 bleeder has helped folks get their brakes restored. Enjoy your victory!

 

[frank8003]

I'm having trouble with my 1972 M35A2. It started with a major air leak that wouldn't let air pressure build past 60 psi at idle. I hooked up my shop compressor to the emergency glad hand and found air rushing out through the slobber tube vent. After doing some research I concluded that my air pack needed a rebuild. I ordered the kit from monkeyboyarmy, removed my air pack, and rebuilt it. Now my air pressure builds to 120 psi and holds pressure for at least 24 hours after shutdown.
After the rebuild I had zero brake pedal, which I'm sure is normal as my system needs bleeding. I built a pressure bleeder following recovery4x4's post and purchased all of the DOT 5 fluid I could find here in town. It is painted on the access panel above my master cylinder "Silicone fluid only." The master was slightly low (about an inch from the top) so I began by topping off with new fluid and then attached the pressure bleeder into the master cylinder cap. So far, so good.
I pumped up the sprayer to ~10psi and began by opening the bleeder on the air pack. After a second, yellow fluid came out along with several large air bubbles. I know that the new DOT 5 fluid is purple, so I was confused by seeing the yellow fluid. Have I done the unthinkable and mixed fluid types, or is older DOT 5 yellow also?
I stopped at that point so as not to cause more problems, but if the fluids are mixed I figure the damage is done and now I will have to replace all of my fluid with the purple DOT 5. Any tips or advice on how I should now proceed? I appreciate any suggestions yall may have for this rookie Deuce mechanic.

I got tired of doing it all over and over again so added a sight glass and the valves as a permanent setup as filler, bleeder, watchful eye king of thing. It was always just Me, No soldier "B".
The best part (my favorite) is the NAPA thingie to put on the wheel bleeder fittin with the one way check valve.