[jocko]

I've had trouble finding an original OEM type, they aren't something you can grab at NAPA. Having said that, since you mentioned very little flow to the front circuit, it sounds as though the shuttle valve may have been tripped (is your red brake light on on the instrument panel?). The valves are usually centered or fully engaged front or rear (to isolate a low-pressure, leaky front or rear circuit), haven't seen one that is partially engaged, but I suppose it could be possible. Anyway, you may want to take a stab at resetting the shuttle valve for the brake warning light. The easy way (which seems to seldom work for me anyway) is to slam on the brakes full force (not when moving) a time or three. If you don't have any leaks it could/should recenter the valve. There is also a proper way to reset it with tools, but who doesn't want to just stomp on the brake pedal? If it doesn't work, and it probably won't, it's worth breaking out your shop manual and reading the procedure for properly resetting the valve.