I have the same problem with my Manual Brakes on my 56. New Cylinders, Shoes, adjusted and bled. Shoes are making full contact with Drum looking at the Pattern. The Master was not replaced but does not appear to be leaking though the back. In order to get high Pedal a quick double Pump is required. I would like to know about this "Residual Valve" that Kultulz has mentioned. Contained in the Master Cylinder I assume? So does the Master require replacement?

  

The MC must be bled before attaching lines (GOOD POINT!).

Shoe arcing is hard to find nowadays as OSHA put a collar on it and today's equipment is expensive.

You can bleed the MC on the car (removes lines and plug or install returns to bowl).  After a few hundred miles the shoes should have seated.

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oldcarmark Posted -

"I would like to know about this "Residual Valve" that Kultulz has mentioned. Contained in the Master Cylinder I assume? So does the Master require replacement?"

In the SGL BOWL MC, the valve (BASIC PN 2178 if you have a catalog) is used to allow gradual return of fluid after brake release (no slamming) and also maintains a steady 10lb. residual pressure on the hydraulic system when brakes are released to  more quickly have the shoes expanded. Without this feature you will have excessive shoe travel.

DUAL RSVR MC have the valve (drums brakes only) in the MC outlet port(s).

The valve was once serviced separately then went to complete kit only. I do not trust vendors sources or off-shore. If I was going to depend on a SGL BOWL MC, I would seriously consider having it restored professionally. Same with wheel cylinders.

   

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If you decide to remove the master cylinder to bleed it properly, there are master cylinder bench bleeding kits you can buy at the local parts store. They are cheap. Basically you are purging the air trapped in the bore of the master. If you do it on a "bench" the easiest way I have found is to put the master in a vice and with the bleeder kit installed, fill the master 1/2 full with brake fluid. Then I use a stout Phillips screw driver to push in the master plunger several times until no more air bubbles are seen. Make sure the tubing remains below the fluid level in the master. You can do this with the master still mounted on the firewall using the brake pedal to pump the master, just make sure all your line fittings on the master are tight or you will spray fluid everywhere.

  Ron Lane,  Meridian, ID

Thanks for the advice on bench bleeding the master cylinder. I find it curious however that the original shop manual makes no mention of bleeding the master cylinder, even after a system overhaul. I'm glad someone else chimed in with the same problem. 3 quick pumps and I get a taller pedal. Scary to drive that way.

I found the Residual Check Valve in the Parts Catalog. Internal in the Master Cylinder. If that's not working correctly that is likely the Cause of the Problem We are both having. I don't know how old the Master is on mine. I had the system repaired with new Wheel Cylinders, Shoes, and Hoses this Spring to pass Safety Inspection after I purchased it.

  

I purchased a new Power Booster and Single Master Cylinder to install on mine this Winter when I have the Motor out. I bought a Single because I have no intention of installing Disc Brakes on this One and I found the Dual Master extends out quite far on the last Car I did with Disc Brakes. I bought this Setup on Ebay.

  

eBay item number:350589822554   The Seller I bought this Power Booster from also has external Residual check Valves that go in the Line from the Master that might solve your problem without going into the Master Cylinder. I have messaged Him to see if I need to ad One with this Master Cylinder because apparently it will work with Disc or Drum which likely means no internal Check Valve is installed.  

  

If you are not going to disc/drum and still using a SGL RSVR MC, why the adjustable proportioning valve?

Also be careful here as using two residual valves in tandem can cause serious problem(s).

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geo56 Posted -

"I find it curious however that the original shop manual makes no mention of bleeding the master cylinder, even after a system overhaul. I'm glad someone else chimed in with the same problem. 3 quick pumps and I get a taller pedal. Scary to drive that way."

A regular system overhaul will not require the MC to be bled separately unless you allow it to drain.          

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