Spongy brakes, 914-4 brakes won't firm up??! Options

[Gearren]

I've had it! I have done everything to the brakes on my car, and I can't seem to get them to stop the car with authority. Best I get is a reluctant coast to a stop. Hardly suitable for street use! I have owned the 73 2.0 since new, and have kept it in the garage since 85. Brakes have always been weak, so as I starterd on the quest to revive the car, the brakes were top on the list. I have rebuilt both front and rear calipers, turned the rotors, new pads, new M/C (17mm), bled the m/c, bled the prop valve, and bled the system at least 10 times! I still have weak/spongy brakes! I want to keep the car stock, however I am tempted to remove the prop valve to see if it is the culprit. Any ideas or suggestions would be appreciated??

[ArtechnikA]

didn't see that you adjusted the parking brake venting clearance; it's critical to good pedal feel. the value published in the Haynes manual is not correct - it's aty least twice too big.

if the venting clearance is too large it will really show up with the sstock 17mm master cylinder. many people mistake the slightly longer pedal travel and increased sensitivity for being spongy. it is possible to use the 911/914.6 19mm master cylinder if everything else has been done correctly and you still don't like the feel.

914's hydraulic system is hard to get bled properly, and the proportioner valve is a major culprit. i don't recommend removing them in an otherwise stock car with otherwise stock brakes, but i know that a lot of people do,

i have used a lot of bleeding techniques and now i've pretty much settled into pressure bleeding while at home and close to the airsource, and using the SpeedBleeder bleedscrews at the track. make sure you're using good fluid -- lots of people alternate between Ate Super Blue and Gold so they can tell at a glance when flushing is complete; i like Valvoline SynPower fluid. just make sure it's a reputable DOT 4 fluid from a fresh container and IMO - especially since you are experiencing sponginess - avoid silicone.