Bleeding The Braking System - APRILIA RS4 125 Service Station Manual

RS4 125

Bleeding the braking system

NOTE
IF AIR CONTINUES TO COME OUT DURING THE BLEED OPERATION EXAMINE ALL THE FIT-
TINGS:
IF SAID FITTINGS DO NOT SHOW SIGNS OF BEING FAULTY, LOOK FOR THE AIR INPUT AMONG
THE VARIOUS SEALS ON THE PUMP AND CALLIPER PISTONS.
CAUTION
DURING THESE OPERATIONS, THE VEHICLE MUST BE UPRIGHT.
NOTE
DURING THE BLEEDING OPERATIONS FREQUENTLY CHECK THE LEVEL TO PREVENT AIR
GETTING INTO THE SYSTEM THROUGH THE PUMP.
WARNING
BRAKE FLUID IS HYGROSCOPIC; IT TENDS TO ABSORB MOISTURE FROM THE SURROUND-
ING AIR.
IF THE LEVEL OF MOISTURE IN THE FLUID EXCEEDS A GIVEN VALUE, BRAKING EFFICIENCY
WILL BE REDUCED.
THEREFORE, ALWAYS USE FLUID FROM SEALED CONTAINERS.
UNDER NORMAL DRIVING AND CLIMATIC CONDITIONS YOU SHOULD CHANGE THIS LIQUID
EVERY TWO YEARS.
IF THE BRAKES ARE USED INTENSELY AND/OR IN HARSH CONDITIONS, CHANGE THE FLUID
MORE FREQUENTLY.
CAUTION
WHEN CARRYING OUT THE OPERATION, BRAKE FLUID MAY LEAK FROM BETWEEN THE
BLEED SCREW AND ITS SEAT ON THE CALLIPER. CAREFULLY DRY THE CALLIPER AND DE-
GREASE THE DISC SHOULD THERE BE OIL ON IT. WHEN THE OPERATION IS OVER, TIGHTEN
THE OIL BLEED SCREW TO THE PRESCRIBED TORQUE.
CAUTION
MAKE SURE THE BRAKE FLUID DOES NOT GET INTO YOUR EYES OR ON YOUR SKIN OR
CLOTHES. IF THIS HAPPENS ACCIDENTALLY, WASH WITH WATER.
WARNING
BRAKE CIRCUIT FLUID IS VERY CORROSIVE; DO NOT LET IT COME INTO CONTACT WITH THE
PAINTED PARTS.
key:
A) A.J.P. Brake calliper
B) J.JUAN Brake calliper
Front
Any air trapped in the hydraulic circuit acts as a cushion, absorbing much of the pressure applied by
the brake pump and minimising the braking power of the calliper.
The presence of air is signalled by the "sponginess" of the brake control and poor braking efficiency.
CONSIDERING THE DANGER FOR VEHICLE AND RIDER, IT IS STRICTLY NECESSARY, AFTER
REFITTING BRAKES AND RESTORING THE BREAKING SYSTEM TO THE REGULAR USE CON-
DITIONS, THAT THE HYDRAULIC CIRCUIT BE AIR PURGED.
NOTE
THE FOLLOWING OPERATIONS REFER TO ONLY ONE FRONT BRAKE CALLIPER BUT APPLY
TO BOTH CALLIPERS. THE VEHICLE MUST BE ON LEVEL GROUND TO BE PURGED. WHILE
PURGING THE HYDRAULIC SYSTEM, FILL THE RESERVOIR WITH THE NECESSARY QUANTITY
Braking system
BRAK SYS - 257