THRUSH AIRCRAFT, INC – MODEL S2R-R1340
AIRCRAFT MAINTENANCE MANUAL
3 - 4
Effective: 01/01/08
BRAKE SYSTEM BLEEDING
Ref. Fig. 3-3
If weak or “spongy” brakes are
experienced, it most likely means that air
has gotten into the hydraulic system for
that side. Air in the brake lines
compresses as the master cylinder is
actuated, allowing less pressure to get to
the brake cylinders.
To eliminate this air the brakes must be
bled, as follows:
1. Ensure that the master cylinder
reservoir is full. Leave the filler cap
off.
2. Have available a clean container of at
least a pint capacity, a length of 3/16”
ID clear plastic tubing, clean rags and
extra MIL-H-5606 hydraulic fluid.
3. Put the clear plastic tubing on one of
the bleeder valves at the bottom of
the brake calipers and open the
bleeder valve with a wrench. Direct
the hydraulic fluid into a clean
container.
4. Have a helper in the cockpit actuate
the brake pedals slowly through a
number of full strokes, ensuring that
the master cylinder reservoir does not
run dry. Refill the master cylinder
reservoir as necessary.
5. Have the helper continue to operate
the brake pedal until the stream of
hydraulic fluid coming out of the
bleeder valve is completely free of air
bubbles.
Figure 3-3: Hydraulic Brakes
