I changed bthe master cylinder and both rear lines, they twisted and rear wheel cylinders. The front are new a year or so ago. I tried pushing a bunch of fluid through the front brakes, still stuck. I then pulled the switch and tried moving the combination through that port, no go. I even tried the original master cylinder because it has bleeder ports and this one looks a bit different, chrome lid doesn't fit😁, still no go. The new master cylinder is going back on, had the pedal go down randomly, probably is 50 years old, so it is probably shot. My plan according to this diagram is unscrew the switch, remove the rear outlet line and push the valve back with a small screwdriver to reset. Thoughts?

 

If you still have the original cast iron combo valve, it's likely there is rust in the bore that is causing the piston to stick. Unless you are doing an optically correct resto, consider replacing it with a brass unit.

 

Cast iron, pretty sure all the brake parts were orginal. From what I can tell it is centered, thin part of the spool is under the sensor, can see a beveled edge on each side. I have flow with brake clean through the inlet to the outlet on both sides Not sure why no fluid is coming from the rear port on the master cylinder on either master cylinder.

 

When you say no fluid from the rear port of the M/C, is that verified by disconnecting the hard line right at the M/C? Or are you really saying that you don't have flow at the outlet of the combo valve? If the latter, I'd check for rust or debris blocking the outlet port. I've seen this before. Try poking in the port opening with a piece of copper wire (to avoid scratching the cast iron parts). If you really do mean there is no flow from the rear port on the M/C, that could be a pushrod adjustment problem.

 

Yes, right at the hard line off the master cylinder. From what I can tell the combination valve is in the proper position.

 

So when you bench bleed the M/C, there's no flow from the rear port?

 

Now that you mention it, there wasn't any amount. I did the plug in method, what came with it, did quite a few strokes. I may try my old master cylinder to see what flow I have from it.

 

Original is the same, there is some flow out it. With the plug in, just a few bubbles bleeding with the plugs in. It make take a **** ton of bleeding to get brakes. I think there was some flow with the new master cylinder, did so much this week.

 

I am getting some flow out of the combination valve, thinking this the route I am going.
https://www.google.com/url?sa=t&sour...OigyZvInXVd_ZH I never had this bleeding issue before.

 

To finish this thread, the Motive power bleeder put fluid at the rear bleeders instantly. I bled them twice, brakes work Ok, I set the rear brakes nice and tight and the fronts may need set tighter against the drums or there is still a bit of air in the system.