Reverse bleeding rear drums

[1stgen68]

Replaced master cylinder due to brake fluid being rusted. Pulling in air at the new master after air bubbles appear even after bench bleeding. Was going to try a reverse bleed from the passenger right and cannot push the fluid through and only comes gushing out of the bleeder screw no matter if it's barely cracked or almost all the way open.  The fronts are bled and only have the back wheels that i cannot push the fluid through. Makes me wonder if i have a corroded line somewhere not allowing the fluid to pass. The steel line coming off the master is taped off and have it attached to a bottle (catch) can if i ever get it to flow correctly.  Would the only option that i have is to start chasing which line or lines contain the blockage starting from both rear wheels and on up to the master?

[z28z11]

Rebuild the distribution block and/or proportioning valve (if so equipped) ? Rusty fuid is not a good sign for whatever you haven't rebuilt downstream - you might disassemble and refresh everything just to be safe. Including flushing the lines - 

Regards,
Steve

[1stgen68]

Yea it has a proportioning valve and maybe that good ole rust has seized the piston inside and needs to be replaced.

[KurtS]

Rebuild. There's a guy that makes quality rebuild kits for all the valves.

[z28z11]

Check this out and I believe you'll find your solution(s). I've got several to do myself -

https://www.musclecarresearch.com/

Regards,
Steve

[x66 714]

I just did one on my 69. Not too bad. Lots of clean up. Had lots of junk in it. Only 3 little seals in their kits.....Joe

[z28z11]

I just did one on my 69. Not too bad. Lots of clean up. Had lots of junk in it. Only 3 little seals in their kits.....Joe

And the right seals, and seal materials. Friend of mine sent his out to a known rebuilder, leaked like a sieve when he installed it, went back and forth a couple of times to get right. I'd rather not trust the import look-alikes, master cylinders, either.

Regards,
Steve

[x66 714]

I just did one on my 69. Not too bad. Lots of clean up. Had lots of junk in it. Only 3 little seals in their kits.....Joe

And the right seals, and seal materials. Friend of mine sent his out to a known rebuilder, leaked like a sieve when he installed it, went back and forth a couple of times to get right. I'd rather not trust the import look-alikes, master cylinders, either.

Regards,
Steve

The kit I used was from the link you provided.
I had to get some brass brushes to get the tarnish off. Need good light & rinses really good with brake cleaner. Maybe I will put a little air to mine now that it's rebuilt. I don't need any leaks...Joe

[KurtS]

https://www.musclecarresearch.com/

Thanks! That who I was thinking of!

[sabino56]

I just went thru similar on my 68 drums all around.  It sat and got rust in MC, rears would not flow. 
You may want to consider reverse flushing brake lines.  In my case, a rear brake cylinder leaked while sitting so there was flow into lines going to rear over time.  I had to reverse flush lines until clear with a pressure bleeder to get them to flow freely.  Also good time to replace soft line if you’re in that far.
I sent my MC and distribution block to Whitepost and they seem to have done a good job.