APRILIA SR 50 Workshop Manual page 46

PERIODIC MAINTENANCE
BLEEDING THE BRAKING SYSTEM
Any air present inside the hydraulic circuit will serve as a
"pad" by absorbing most of the pressure coming from the
brake master cylinder, thus reducing caliper efficiency during
braking. If air is present inside the circuit, the brake control
is "spongy" and braking efficiency is reduced.
DANGER
It is essential to bleed air out of the hydraulic
circuit after the brakes have been refitted and
the braking system has been restored to
standard operating conditions, as it would be
very dangerous for the vehicle and the rider not
to do so.
•
Loosen the two brake fluid reservoir screws.
•
Raise and remove the cover (1).
CAUTION It is recommended to keep the fluid even with the
edge of the reservoir (horizontal) in order not to spill fluid
when topping up.
•
Remove the gasket (2).
•
Top up fluid, if necessary.
•
Remove the bleed valve rubber cap.
•
Connect a clear tube section to the bleed valve.
WARNING
Do not soil brake pads or discs with brake fluid.
•
Put the free end of the hose into a receptacle.
•
Slowly pull the brake lever completely two or three
times, then keep it pulled.
•
Loosen the bleed valve, press the lever and check if air
bubbles are coming out of the tube together with the
fluid.
WARNING
Tighten the bleed valve before releasing the
lever in order to prevent air from getting into
the brake circuit.
• When air is no longer coming out, tighten the bleed
valve and release the brake lever.
CAUTION Repeat the last three steps until the air bubbles
have been completely eliminated.
WARNING
After reassembly, repeatedly pull the brake
lever and check the braking system for correct
operation.
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SR 50