APRILIA SR 50 Workshop Manual page 41

PERIODIC MAINTENANCE
BLEEDING THE BRAKING SYSTEM
The air, if any, present inside the hydraulic circuit will serve
as "pad" by absorbing most of the pressure coming from the
brake master cylinder and thus reducing the calliper
efficiency during braking. If some air is present inside the
circuit, the brake control is "spongy" and the braking
efficiency is reduced.
DANGER
It is fundamental that air is bled off the
hydraulic circuit after the brakes have been
refitted and the braking system has been
restored to its standard operating conditions,
since it would be very dangerous for the
vehicle and the rider not to do so.
• Loosen the two brake fluid tank screws.
•
Raise and remove cover (1).
CAUTION It is recommended to keep the fluid parallel to the
tank edge (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 disc 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 bleed valve before releasing the lever
in order to prevent air from getting in 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 completely
eliminating the air bubbles.
WARNING
After reassembly, repeatedly pull the brake
lever and check the braking system for correct
operation.
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