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]

Why hasn't anyone recommended specific pads?

because the "right" pad is highly dependent upon specific application, and the intended use of the vehicle in question has not yet been mentioned.

i'm using MetalMasters on my street car; i'd recommend them for a street application. there are other pads that are okay on the street.

but this is definitely a place where counterintuitively, "race brakes" don't stop well on the street. they achieve their high performance only at high temperatures and are little better than blocks of ice for that first stop sign on cold brakes in the morning... once hot they work great - but some of them achieve their high friction levels by being extremely abrasive on disks. good disks are expensive and i don't like replacing them any more often than necessary, even if i -can- do it without a bearing change on my car. (actually, bad disks are expensive too, because you'll use up 3 bad disks in the same usage as one good one ...)

IMO - go with the softest pad that won't disintegrate in its intended use.

i thought it was interesting to hear a NASCAR crew chief say the same thing about one of their short-track cars. while the total energy dissipation is the same, a soft pad will slow you faster, which means you can stay on the gas longer, and because it will slow faster to cornering speed, it means you can get -off- the brakes sooner, giving them more time to cool.

but 30 yrs ago, endurance cars were changing brakes about every 6 hrs - 3x a race, and now they MIGHT change pads once, at half distance - and the cars are going faster and stopping shorter than they did back then. the technology has come a long way...