TEST OR INSPECTION
AUTOMATIC BRAKE VALVE
21. LARGE CAVITY EXHAUST OF THE BRAKE VALVE LEAKS WITH HANDLE IN RELEASE POSITION.
Step 1. Check to see if there is a light blow of air at the brake valve housing exhaust.
Replace O-ring on emergency valve of automatic brake valve (last O-ring) or replace O-rings on
suppression valve of automatic brake valve (1st, 2nd, or 5th O-ring) (para 4-11).
Step 2. Check to see if there is a heavy blow of air at brake valve cavity exhaust and no brake pipe pressure.
Replace O-ring on cutoff portion of the A-1 charging cutoff pilot valve (bottom O-ring) (para 4-15).
22. REGULATING VALVE EXHAUST (LOCATED IN SPRING HOUSING NEAR REGULATING VALVE HANDLE) OF
THE AUTOMATIC BRAKE VALVE LEAKS.
Step 1. Check to see if the equalizing reservoir pressure approaches main reservoir pressure.
Replace regulating valve diaphragm of automatic brake valve (para 4-11).
Step 2. Check to see if the equalizing reservoir does not register full pressure, and brake pipe charges slowly;
during an automatic brake application, brake pipe exhaust is at the regulating valve.
Replace relay valve diaphragm of the automatic brake valve (para 4-11).
Step 3. Check for a continuous blow at exhaust port on top of the automatic brake valve.
Replace supply valve in the relay valve portion of the automatic brake valve (para 4-11).
INDEPENDENT BRAKE VALVE
23. THERE IS CONTINUOUS BLOW FROM THE EXHAUST WITH THE HANDLE IN RELEASE POSITION.
Step 1. Check to see if there is a heavy blow of air from exhaust.
Replace O-ring on spool valve separating main reservoir supply and line 20 of the independent brake
valve (center 0-ring) (para 4-12).