brownish brake fluid in rear barrel

[Pops]

It's probably a no-brainer, but discolored brake fluid in the rear barrel of dual master is not a good sign. The fluid is full, but color is off - like someone stirred in a little cocoa. I also hear a little chirp coming from rear brake. Sound familiar? Wisdom and experience welcomed.

What's been changed from all appearances:
1. Drums and shoes
2. Dual master (not sure when)
3. Power booster (not sure when)
4. Brake lines
Note: overall restored vehicle sometime in last 10 years.

I haven't pulled rear wheels lately, but as I recall, the wheel cylinders looked older than all other brake parts. Especially in rear.

I'm looking forward to the day when I can just drive this doggone truck. Ya know what I mean?

[Pops]

LOL. Forgot this dumb question was still out there. Anyway, one of the PO had put a glob of jb weld or something on the front vent hole (67 dual barrel MC) within the front barrel of the MC. This was compromising the re-circulation of the brake fluid going to the rear. I'm not sure the reasoning for this but for future readers, I believe it was the PO attempt to modify fluid pressure similar to what a proportioning valve would do. As for now, putty stuff gone.
Added to the above, the truck sat for years even though restored. I assume moisture, etc. Hence brownish fluid.
So there. I finally got a response. Unfortunately I think Im talking to myself.

[AZKen]

Don't know if you still have a question or not, but here is the answer to the 2014 post:

Sorry to bring bad news. You need all new stuff. Master, all lines, wheel cylinders. I think you probably know that. Now I've said it. I know you can say "new lines already, blow them out, clean this, clean that". But telling you what I would do, and have done. Brakes and steering can't be anything but right. You have bad fluid circulated everywhere and possibly residue from the fit-it putty. You can't sleep with that. Good night.

[Pops]

AZ. I changed the fluid a few times and that seems to have corrected the problem. I did make some other brake improvements but I did not change wheel cylinders. It's been about 1500 miles on new fluid. Perhaps I caught it in time to avoid consequences. Brakes are working much better than when I purchased the truck.

[AZKen]

Sounds good. Probably no harm after flushing.