Dodge Repair: Cant bleed R Front & L Rear brake lines

Question
1999 Chrysler Concorde. (does not have ABS)

Background: Bought car, noticed L rear wheel (possibly emergency brake) was getting extremely hot, and wheel was binding. Removed emergency brake parts, which stopped the binding. Then started to drive car, and it lost brake pressure. Looked under hood, and one of the rusted brake lines from the Master Cylinder was leaking profusely.  Replaced bad line with new line.  Fixed leak, and have not had any more leaks since.

Was able to bleed the L front and R rear, but not R front & L rear. Then tried vacuum bleeder on R front and L rear and after much time, and multiple attempts, could get no fluid to bleed, and reservoir stayed full.  Left the brake bleeders for both wheels open overnight, to see if anything would drain, and it didn't.

Brake light only comes on momentarily, like rest of lights, when car is started.  Afterwards, the brake light NEVER comes on, whether I pump slowly, hard, repeatedly, etc.  And, the car is not throwing any codes.

QUESTION:  Do you think it is the Master Cylinder?  If so, what is the easiest way to test, before I buy and replace the cylinder?

Thank you very much.  Gary

ANSWER: Hi Gary,
Given split design and the history of rust in the brake line I would first suspect that there is rust in the half-system between the master cylinder and the R Front L Rear ports of the system. It could be in the junction block which is located behind the forward half of left inner fender shield. You will find 2 inlets from the master cylinder and 4 outlets there and so you could check whether the outlets for those 2 pathways that won't bleed are clogged up. If so you could either clean out the junction block or replace it. The inboard  inlet port of the junction block is what brings the brake fluid from the master cylinder which supplies the output pathways that won't bleed.
The master cylinder itself is unlikely to fail in the manner that you describe.
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Thanks for doing that.
Roland




---------- FOLLOW-UP ----------

QUESTION: I checked the two outputs at the Master Cylinder (MC). One had fluid coming out, and the other didn't, but gurgled a little when I first loosened the nut, and then the brakes started to stiffen up some, and the R front, and L rear started to bleed, and we were able to complete the bleeding.

But then after starting the car to try to check the brakes, the pedal went to the floor. And, we discovered the L rear brake line had sprung a leak (new problem).  It had a lot of rust around the place it started leaking.

Now, I am planning on replacing the line. But, I don't understand why the one MC output never had any fluid come out when we checked it.  We were pumping, holding the pedal down, and then loosening the nut.  With one of the outputs, the fluid gushed, but with the other nothing came out.

Thanks again for your help.

Answer
Hi Gary,
Due to previous leaking that half of the MC might have been virtually drained of fluid and although you put fluid in the reservoir it may still have air inside of it. You can try bleeding both ports of the MC, recycling the fluid back in the input opening and do that sufficiently until you would believe that trapped would be bled out. Then see how the outputs compare, or try reattaching the lines to the MC and bleeding at the wheel cylinders.
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Thanks,
Roland