It was super cool to get behind the wheel, even though I'm sitting on a 6x6 piece of wood.

so bleeding the master and front went OK; we got nothing on the backs.

I suspect the brake pressure regulator needs to be wacked or something.

Please advise before I do something stupid.

Some videos show a different BPR, this is a 75'

Click to view attachment

I would get a GOOD flare nut wrench and try to bleed at the line going IN to the regulator, then once the air is done "popping" at that location, pick an outlet line and try it there...then if all goes well move to the caliper. If at some point you are not succesful, then your restriction is between that point and the last one that you were able to bleed.

Have a water hose ready to rinse off whatever brake fluid spills on painted surfaces

The first time my dad showed me how to bleed brakes, I spent more than 30 minutes pumping the pedal until my leg went numb as he cursed from the back of the car that no fluid was coming out. Something must be wrong. Could the mc be completely bad? Clogged lines? Getting nothing but a dribble out of the bleeder and the pedal is still soft going all the way to the floor. After nearly an hour of pumping the pedal, I looked down and realized I had been pumping the clutch the entire time. It wasn’t funny at the time, but we laugh about it now.

Sorry this probably isn’t constructive, but thought I’d share.

Are your rear soft hoses expanded closed/clogged?

That reminds me of a time we had a VW and the starter died when we were on vacation. Mom was in the drivers seat and me and dad had pushed this POS up and down the street 15 times trying to bump start it before my dad went to check if the key was turned on. Lol. And it wasn’t.

that's f'ng hilarious. Thanks for sharing. I remember holding wrenches and holding the light the wrong way with my dad a long, long, time ago.

We put new SS hoses on.

OK, thanks. We'll get on that on Monday.

So is the BPR adjustable??

the alien screw and nut on the left indicates it should be, but it was not possible to move without rounding off the nut.

Regulator is set at at a specific brake pressure knee point. It is not meant nor should it be user adjusted. It’s operation and operational set points (914/4 vs 914/6) are outlined in the factory service manual. I don’t have the chart with me at the moment but it is a straight pass through of rear brake pressure initially.

Adjusting the regulator will not help you bleed the rear brakes.

Get Speed Bleeders (PMB?), a long length of clear tubing that fits the SBs (long enough to reach the floor outside the driver’s side door from the right rear) and a catch jar. Makes bleeding the brakes a one person job as you sit in the driver’s seat with the door open. No telling the helper ‘pump, pump, pump, hold, release’ repeatedly. Right rear, left rear, right front, left front. That order. You will see air bubbles going down the line. Get a big bottle of brake fluid. Don’t bleed the reservoir to empty.

All of this and a Motiv power bleeder will make short work of it.

I'm the helper. My son, an ASE certified mechanic, is doing the bleeding.

We are not getting fluid to the rear calipers.

Fronts are fully bled.

You might have better luck using a pressure bleeder to move fluid through system. You either have blockage, a leak, or not enough fluid in the system.
Did you install a new MC? If you haven't removed the belly pan/mc cover yet (or put it back after installing the MC), remove it and check there for a leak.

Have you checked to see if the line is blocked going into or out of the regulator yet?

When bleeding brakes on a 914, I've always read to start with the right rear (furthest away from the MC).

If the MC is oldder the piston can get stuck in the end of MC , if you fully stroke ..while pumping...

We didn't put a new MC. The car was completely disassembled, painted, and now being reassembled.

there is fluid coming out of the feed line. we did start with the rears but when no fluid went to the fronts. they bled fine.

OK, we'll check this out