Bleeding the Brakes (6520 and 6620 Tractors)
NOTE: To avoid oil foaming while bleeding, the procedure should not be started after fast driving, working with hydraulic implements or carrying out hydraulic tests. After such operation the tractor should be allowed to stand for one hour to allow the oil to lose any accumulated foam. Bleeding points: Without trailer brake: 1.
Left rear brake
With hydraulic trailer brake: 1.
Left rear brake
With air brake system: 1.
Trailer control valve, rear bleed screw
With air brake system and FWD with brake: 1.
Left front brake
With hydraulic trailer brake and FWD with brake: 1.
Left front brake
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CAUTION:
Always follow the steps described here precisely. This is the only way of assuring the tractor brakes have been correctly bled.
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Bleeding procedure: 1. With the engine running, turn the steering wheel slowly and evenly two or three times from left full lock to right full lock and back again. This fills the brake valve housing via the steering valve return line. Shut off the engine.2. As shown in the relevant illustration, slide two transparent bleed tubes over the appropriate bleed screws. Place the other ends of the two bleed tubes in the oil filler neck. 3. Open the bleed screws by half a turn. 4. Start the engine. 5. Brake pedals must be coupled together. Apply gentle pressure to the brake pedals and hold them in this position until the fluid escaping from the bleed screws is free of air bubbles. 6. Then depress the pedals briefly and release. Repeat this a few times. This should flush out any air bubbles left in the fluid. 7. If necessary, repeat step 5. 8. Hold the pedals in the depressed position and close the bleed screws. |
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9.
Shut off the engine and actuate the brake pedals several times each (separately!) with the engine shut off. This bleeds the last of the air out of the brake valve. There must be perceptible (increasing) resistance before each pedal reaches its limit of travel.
IMPORTANT: If pedal does sink noticeably after resistance has been reached, leaks in the brake system may be the cause. |
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