Brake Bleeding Procedure

TX1074581A-UN-29MAR10

Brake Bleeding Procedure using Bleed Screw Method

T6838AE-UN-26OCT88

1 - Brake Line (2 used) (right and left)

2 - Bleed Screw (2 used) (right and left)

CAUTION: Do not operate machine if pedal travel exceeds 133 mm (5.25 in.) while applying 267 N (60 lb-force). Operating machine with excessive brake travel could cause brakes not to stop machine on first application.

NOTE: Air will "gravity bleed" from service brake system through brake valve without use of bleed screws but the procedure may take much longer so bleed screw method is the recommended procedure. Brake lines must be inclined toward brake valve for procedures except for the bleed screw method.

Low ambient temperature or aeration of oil will slow bleed process.

The rear axle is equipped with two brake bleed screws, one for each wheel. Brake bleeding must be done whenever the brake system has been opened to repair or after replacing the brake valve, brake lines, fitting, O-rings or axle internal brake parts.

All fittings must be inspected for leaks and tightened if leaks occur

The preferred method for the brake bleeding procedure is to use the bleed screw method. The vacuum and manual methods are much slower methods but can be used as alternate method.

Bleed Screw Method (S.N. —910944)

NOTE: Two people are required to bleed brake system oil, one to operate brake valve and other to open and close bleed screws.

1. Engage park brake.

2. CAUTION: Hot oil can cause serious burn injury. Secure drain hose on bleed screw and in container to prevent it from blowing off when bleed screw is opened while brakes are applied.

   Secure a clear plastic tube on bleed screw (2) with hose clamp and secure other end in a small container.

3. Run engine at fast idle. Dump and curl backhoe bucket five times to assure fluid level in brake reservoir.

4. Open the bleed screw, depress the brake pedal, close the bleed screw, and allow the pedal to return to neutral.

   Repeat the process until the oil runs clear without air. During bleeding cycle process operate dump and curl bucket function again 5 times to refill the brake valve reservoir.

5. Repeat process for opposite side.

6. After bleeding process is completed pump both pedals together to check if pedals are firm.

7. Check pedal travel to specification.

   Item	Measurement	Specification
   Dual Brake Pedal Travel	Max. Distance	95 mm (3.75 in.)
   Single Brake Pedal Travel	Max. Distance	114 mm (4.5 in.)

8. Recycle old oil.

Bleed Screw Method (S.N. 910945— )

NOTE: Two people are required to bleed brake system oil, one to operate brake valve and other to open and close bleed screws.

1. Engage park brake.

2. Secure a clear plastic tube on bleed screw (2) with hose clamp and secure other end in a small container.

3. Run engine at slow idle.

4. Steer from stop-to-stop 3 or 4 times to fill the brake valve reservoir.

5. Open the bleed screw, depress the brake pedal, close the bleed screw, and allow the pedal to return to neutral.

   Repeat the process until the oil runs clear without air. During bleeding cycle process, steer stop-to-stop 3 or 4 times to refill the brake valve reservoir.

6. Repeat process for opposite side.

7. After bleeding process is completed pump both pedals together to check if pedals are firm.

8. Check pedal travel to specification.

   Item	Measurement	Specification
   Dual Brake Pedal Travel	Max. Distance	95 mm (3.75 in.)
   Single Brake Pedal Travel	Max. Distance	114 mm (4.5 in.)

9. Recycle old oil.

Vacuum Method

1. Engage park brake. Connect a vacuum to breather port on hydraulic reservoir. After 10 minutes, disconnect air pressure.

2. Leave hose from breather port to vacuum device connected until brake circuit is filled with oil. Both pedals should become solid.

3. Check pedal travel to specification.

Manual Method (S.N. —910944)

1. Engage park brake. Run engine at fast idle. Dump and curl backhoe bucket five times.

2. Pump left-hand brake pedal five times, allowing two seconds between each pump for air to escape.

3. Repeat steps 1 and 2 until the left-hand pedal is solid.

4. Pump right-hand pedal until pedal is solid, then both pedals together until pedals are solid.

5. Check pedal travel to specification.

Manual Method (S.N. 910945—)

1. Engage park brake. Run engine at slow idle.

2. Steer from stop-to-stop 3 or 4 times to fill the brake valve reservoir.

3. Pump left-hand brake pedal five times, allowing two seconds between each pump for air to escape.

4. Repeat steps 1 and 2 until the left-hand pedal is solid.

5. Pump right-hand pedal until pedal is solid, then both pedals together until pedals are solid.

6. Check pedal travel to specification.