Trouble Shooting -Gyros - Cessna 150 Series Service Manual

15-26. TROUBLE SHOOTING--GYROS.
TROUBLE PROBABLE CAUSE REMEDY
HORIZON BAR FAILS TO Central filter dirty.
Check filter. Clean or replace
RESPOND.
filter.
Suction relief valve improperly Adjust or replace relief valve.
adjusted.
Faulty suction gage.
Substitute known-good suction
gage and check gyro response.
Replace suction gage.
Vacuum pump failure. Check lump. Replace pump.
Vacuum line kinked or leaking. Check lines for damage and leaks.
Repair or replace damaged lines,
tighten connections.
HORIZON BAR DOES NOT Defective mechanism.
Substitute known-good gyro and
SETTLE. check indication. Replace
instrument.
Insufficient vacuum or leaking
Adjust or replace relief valve. Tape
gyro.
seal horizon gyro case.
Excessive vibration. Check panel shock-mounts.
Replace defective shock-mounts.
Change 1 15-10A/(15-10B blank)