Trying to bleed brakes, but nothing comes out?

[BoldUlysses]

Hi guys.  Hoping for some insight into what's going on with my left rear drum brake.  So my car is a 7/72 build, right on the cusp when the brake system was updated.  It has the older-style wheel cylinders (with the line coming off at an angle rather than perpendicular to the backing plate) BUT it has the newer-style brake line routing, with the proportioning valve in the engine bay:

The older-style wheel cylinders are very hard to find replacements for, but I was able to find rebuild kits and rebuilt both.  New steel drums and all hardware on both sides. 

The problem is that although I'm able to get fluid to come through the bleeding screws on all 3 of the other brakes, nothing comes out of the left rear with the screw open and an assistant pumping the pedal.  Do I have a blockage?  Is something else going on?  Has anyone else experienced this issue?

Thanks for any and all help.

 

Edited July 2, 2020 by BoldUlysses

[heyitsrama]

You might have blockage inside the line. In the past I’ve cleaned out lines by using compressed air. I would remove the brake cylinder off the line to avoid getting debris inside the cylinder. 

[Yarb]

Have you tried cracking the line loose at the junction block to see if you have pressure there? Either way you’ll find out if it’s the line or the block.

[BoldUlysses]

1 minute ago, Yarb said:

Have you tried cracking the line loose at the junction block to see if you have pressure there? Either way you’ll find out if it’s the line or the block.

That's a good call—undoing the line further up to try to find out where the blockage is.  Will do it and report back.  Thanks!

[cgsheen1]

Pull the bleeder screw all the way out and stick a bit of solid wire (something stiff and very small diameter) in there. There may be some corrosion just beyond where the bleeder seats.