#8 – Hydraulic Reservoir Servicing

Many aircraft coming into our facility show evidence of reservoir over-servicing. The proper procedure is given in the Maintenance Manual, Ch. 12-10-03, page 201. Be sure to observe closely the requirements to:

1. Bleed off the hydraulic pressure with the manual release valve (hiding forward and below the pressure gauges at the access panel).

2. With electrical power off or Emergency Pump C/B pulled, pump the brake pedals until the emergency pressure is zero. (Note: The pressure gauge should "hang" at a value above zero for several pumps. This pressure is the charge on the accumulator. If the gauge doesn't "hang", you've lost the nitrogen charge and should have it serviced as well.)

3. With your fingernail, open the relief valve on top of the reservoir to bleed off the air pressure.

4. The sight glass should show the fluid level to be between ½ to ¾ of the glass. Do not service above ¾ of the glass.

NOTE: The thrust reversers and lift dumps must be in the stowed position during this check, and we sincerely hope the gear is down and locked.