This procedure tells you how to replace these parts on ST and DS lathes.

1. brake caliper
2. brake rotor
3. hydraulic cylinder
4. c-axis motor

This procedure is shown on a ST-30 Lathe with live tooling.

Remove the workholding (chuck/collet) from the spindle.

On the Haas Service Guide search for Lathe - Chuck - Install for more information.

Put tape on the drawtube threads. This protects the threads.

Set: Parameter 278:26 C-AXIS DRIVE to 0.

Push [POWER OFF].

Set the main circuit breaker to the OFF position.

Lock the main circuit breaker. Use an approved lock with an approved safety tag.

Remove the (4) brake caliper mounting bolts [1]. Remove the brake caliper.

Disconnect the brake solenoid [2] cable [3].

Put a mark on one of the hoses [6] for the hydraulic cylinder to make sure you put the hoses back in the correct position.

Remove these components:

• C-Axis motor and encoder cables [1]
• C-Axis motor mounting bolts [2]
• C-Axis motor [3]
• (4) C-Axis motor mounting plate screws [4]
• oil return hose [5]
• (2) hydraulic cylinder hoses [6]

To protect parts from contamination:

1. Put the ends of the hydraulic cylinder hoses in a plastic bag. Use cable ties to hold the bag on the hoses.
2. Put plugs into the inlet holes.

 Note: The belt is removed in this image. It does not need to be in this step.

Remove all of the screws [1] for the brake rotor mounting.

 Note: The number of screws is different on different machines.

Support the weight of the hydraulic cylinder. Loosen all of the screws [2] for the hydraulic cylinder.

Remove the hydraulic cylinder [2] and drawtube [3] together.

Remove the drawtube from the hydraulic cylinder.

Examine the used spindle drive belt. If the used spindle drive belt is damaged, remove the (8) hydraulic cylinder mounting plate SHCS [1].

Remove the plate and the brake rotor.

Loosen the (4) spindle drive belt lock screws [1].

Adjust the jack screws [3]. This loosens the tension on the spindle drive belt [2].

Remove the spindle drive belt [2].

Examine the hydraulic cylinder adapter, brake rotor, caliper, pads, and spindle drive belt. Replace all damaged parts.

Install the spindle drive belt [2] onto the pulleys. Adjust the tension of the spindle. Refer to Lathe - Drive Belt Tension - Gates Sonic Meter - Instructions .

Torque the (4) spindle drive belt lock screws [1]. Refer to the Haas Fastener Torque Specifications. Use the value for steel.

Put the new rotor [1] on the spindle adapter.

Install the hydraulic union adapter [2] for the hydraulic cylinder. Use your hand to tighten the screws [3]. Tighten the screws [3] in a star pattern.

Adjust the rotor and adapter until they are centered correctly. Use an indicator to measure these errors:

1. The inner surface [4] of the adapter must be centered within 0.001" (0.03 mm) total indicated runout (TIR).
2. The face [2] of the adapter must be perpendicular to the spindle centerline within 0.001" (0.03 mm) TIR.

Torque the rotating hydraulic cylinder adapter screws in a star pattern. Refer to the Haas Fastener Torque Specifications. Use the value for steel.

Examine the drawtube for damage to the threads.

Put tape on the threads [2] of one side of the drawtube to protect them.

Apply medium-strength thread locking compound to the last (4) drawtube threads.

Turn the otherside [1] of the drawtube into the hydraulic cylinder. Continue to turn the drawtube until it stops.

Turn the drawtube in the opposite direction (4) turns.

Install the hydraulic cylinder and the drawtube together as an assembly.

 Note: The belt is removed in this image. It does not need to be in this step.

Support the weight of the hydraulic cylinder. Install and hand tighten all of the hydraulic cylinder screws [1] and the brake rotor screws [2]. Tighten the screws in a star pattern.

 Note: The number of screws is different on different machines.

Measure the outside face [3] of the hydraulic cylinder. Use an indicator.

Adjust it to 0.001" (0.03 mm) or lower TIR. Use the hydraulic cylinder screws [1] and the brake rotor screws [2].

Torque all of the screws. Refer to the Haas Fastener Torque Specifications. Use the value for steel.

Make sure the face of the brake rotor is correctly centered. The error cannot be more than 0.04" (1.0 mm).

If the error is more than 0.04" (1.0 mm) loosen the hydraulic cylinder screws [1] and the brake rotor screws [2] and repeat this step.

Hydraulic unions, hydraulic adapters [2] and adapter gaskets [1] have a drain hole [3]. You must align all drain holes with the coolant collector’s drain hole.

 Note: Align all drain holes in the bottom position even if the hydraulic union does not have a drain hole.

 Note: To torque screws in this step, refer to the Haas Fastener Torque Specifications. Use the value for steel.

Install these components:

• Hydraulic hoses [1]. Use the mark you made before.
• Hydraulic return hose [2].
• C-Axis motor mounting plate. Torque the (4) SHCS [3].
• C-Axis motor [4]. Torque the (4) SHCS [5].
• (2) C-Axis motor cables [6].

Install the brake caliper with the (4) mounting screws [1]. Use your fingers to tighten the screws.

Set the spacing of the caliper to the gear disk by using a 0.005" (0.13 mm) shim between the fixed portion of the brake caliper and the gear disc.

 Note: The shim is temporary. It will be removed later.

Connect the brake solenoid [2] cable [3].

Set the main circuit breaker to the ON position.

Push [POWER ON].

Zero Return all axes. Enter MDI mode. Type M14, then press [CYCLE START] to clamp the brake assembly.

Torque the (4) SHCS. Refer to the Haas Fastener Torque Specifications. Use the value for steel.

Push [RESET].