System Bleeding
WARNING:
Do not use previously used brake fluid. Ensure that only new fluid is used and that it is taken from a clean sealed container. Carefully dispose of unwanted fluid in a sealed container, marked "Used Brake Fluid".
CAUTION:
Clean all bleed screws, filler cap and connections thoroughly using clean brake fluid only. DO NOT use mineral oil i.e. engine oil etc. Maintain cleanliness throughout procedure.
NOTE:
During bleed procedure reservoir fluid level must not fall below "MIN" level. Regularly check level and keep topped up to "MAX" level.
NOTE:
Bleed system using a bleed tube and a clean bottle containing a small amount of clean liquid.
- Switch off ignition and depressurize system. See DEPRESSURIZING SYSTEM . Ensure that ignition remains OFF until step 7 .
- Fill fluid reservoir with specified fluid to "MAX" level. See Fig 1 .
- Depress brake pedal slowly and progressively 5 times, using full pedal stroke. Release pedal for 5 to 10 seconds, during this time air bubbles will rise into reservoir.
- Repeat step 3 until some resistance is felt. If no resistance is felt check that clevis pin is connected to correct (UPPER) hole in brake pedal.
- Bleed 4 front caliper lower (Hydrostatic Circuit) bleed screws in conventional manner. See Fig 2 . Proceed in order: outer bleed screw on drivers side, opposite caliper outer bleed screw, inner bleed screw, inner bleed screw driver's side. Depress brake pedal slowly and progressively, locking bleed screw at bottom of each stroke.
- Bleed hydraulic pump. Open bleed screw on pump and allow fluid to flow until it is clear of air bubbles. See Fig 3 . DO NOT use bleed bottle, use a clean absorbent cloth to prevent fluid spillage.
- Bleed accumulator. Open bleed screw. See Fig 3 . If vehicle is equipped with Electronic Traction Control (ETC), accumulator bleed screw is on top of ETC valve block. On all models, switch on ignition, run pump for 3-4 seconds, switch off and repeat procedure until no further air bubbles enter bleed bottle. Switch off ignition. Close bleed screw.
- Bleed 2 hydraulic booster bleed screws. See Fig 3 . Open one bleed screw, depress brake pedal, switch on ignition, run pump until no further air bubbles enter bleed bottle. Close booster bleed screw, switch off ignition and release pedal. Repeat for other bleed screw.
- Bleed Power Circuit at 4 calipers in turn. See Fig 2 . Depress pedal, open bleed screw (upper bleed screw on front calipers). Switch on ignition, run pump for 3-4 seconds. Switch off and repeat procedure until no further air bubbles enter bleed bottle. Switch off ignition close caliper bleed screw, release pedal.
- Bleed master cylinder. Switch ignition on. System pressure will increase until pump cuts out. If pump does not cut out after running for 45 seconds check system for leaks.
- Bleed Hydrostatic Circuit calipers. Open one front lower caliper bleed screw. Actuate brake pedal several times, using only lower 2/3 of pedal travel, until no further air bubbles enter bleed bottle. Stop actuation if fluid warning light comes on and allow pressure to build up.
- Close caliper bleed screw before releasing pedal, repeat for remaining 3 Hydrostatic Circuit caliper bleed screws.
- Check/top up reservoir fluid level. See CHECKING & ADDING FLUID under SERVICING.
- Dry all connections, fully pressurize system and check for leaks. If 2 full brake applications switch on pump, from fully charged, rebleed system.
NOTE:
Time consumed in filling booster may be reduced by fitting a rubber bellows unit to filler neck, and using hand pressure to pressurize reservoir. A spare bellows unit from booster push rod is suitable for this purpose. Ensure bellows unit is perfectly clean to avoid foreign matter entering system. Raising rear of vehicle will assist fill procedure.