UMC - B Axis Brake Replacement

Last updated: 06/22/2023

UMC- B Axis - Brake Replacement

AD0474

Revision B - 10/2025

Introduction

This procedure explains how to replace the B axis Brake Ring on Reboot UMC machines.

Note: To identify which iteration of these machine models you are dealing with, refer to UMC-750 Machine Version - Identification.

Note: To find the weights for safe lifting purposes, refer to UMC Rotary Unit – Weight Reference Guide.

This document applies to the following service kit:

93-3111 18.39 OD ROTARY BRAKE ASSY KIT (UMC-750/SS, UMC-1000/SS, and UMC-1250/SS)
93-3108 14.39 OD ROTARY BRAKE ASSY KIT (UMC-500/SS)

You should not do mechanical or electrical machine repairs or service procedures unless you are qualified and knowledgeable about the processes.

Only authorized personnel with the proper training and certification should do this repair procedure.

All information herein is provided as a courtesy for Haas machine owners for reference and illustrative purposes only. Haas Automation cannot be held responsible for repairs you perform. Only those services and repairs that are provided by authorized Haas Factory Outlet distributors are guaranteed.

Important: Damage to brake ring will occur if air supply is not disconnected and purged from machine before beginning procedure.

Tools Required

Lifting Aid T-2194A
T-0128 for UMC-750/1000 Brake Indicator Holder or T-0129 for UMC-500 Brake Indicator Holder
5% MOBIL MOLY GREASE (P/N: 99-1792)

C Axis Removal

1

Disable the C-Axis by changing parameter 7.004 to 1.

2

Remove the bottom cover from the C-Axis. Then, unwire the C-Axis servo motor and the scale.

3

Remove the 4 bolts that attach the C-Axis body to the B-Axis platter. (See Image)

4

Remove these 4 bolts.

5

Install the T-2194A lifting aid.

6

Remove the A-Frame support bolts and shims. Then, remove the A-Frame support.

7

Use the eye bolt installed on T-2194A to hoist the C-Axis with a forklift or crane.

8

Remove the remaining bolts that attach the C-Axis body to the B-Axis platter. (See Image)

9

Remove the C-Axis assembly from the machine.

B Axis Platter Removal

1

Home the B and C-Axis.
Press the Emergency Stop button.
Open the lube panel on the tool-changer side of the machine.
Rotate the ball valve shown to cut off air the machine.
- The wings of the valve should be perpendicular to the pipe.

Purge excess air pressure from the machine by pulling and holding the ring on the purge valve until you no longer hear air escaping.
Note: The initial pull of the ring will make a popping sound. This is normal.

2

Remove sheet metal panels at the back of the enclosure to access the B-Axis brake assembly.
Locate the hydraulic line [1] and B-Axis brake boosters [2]

3

Remove the brake line from both B-axis boosters

Important: Damage to brake ring will occur if air supply is not disconnected and purged from machine before beginning procedure.

4

Install a Male 7/16"-20 O-Ring Boss fitting (dash number -04) into the booster where the brake line was removed.

5

Open the lube panel on the tool-changer side of the machine.
Rotate the ball valve shown to return air to the machine.
- The wings of the valve should be parallel to the pipe.

6

Remove the hydraulic line from the the B-Axis brake by removing the fitting shown.

7

Make sure the brake booster is disconnected from the rotary before continuing. If the brake is pressurized with the platter removed, it will become damaged beyond recovery.

8

Remove the platter.

9

Inspect the brake surfaces.

B axis Brake Removal

1

Remove the 10 bolts shown. (See Image)

Then, remove and replace the B-Axis brake if needed.

B Axis Brake Installation

Requirement: Verify machine is equipped with Brake Regulators. Reference the following AD documents: UMC Brake Booster Regulator Service Kit - AD0601

1

Clean the new brake ring and brake ring mounting surface on the B axis body.

Feed the hose through the opening in the bottom of the casting. Do not connect the opposite end of the hose to the T fitting on the master cylinder at this time. Snug the 10 screws and back them out 1/4 turn.

2

Using the T-0128 for UMC- 750/1000 or T-0129 for UMC-500, indicate the OD of the brake ring and adjust to NTE: 0.001” TIR. Torque the brake ring mounting bolts per Haas torque chart

3

Using the T-0128 for UMC- 750/1000 or T-0129 for UMC-500, indicate the OD of the brake ring and adjust to NTE: 0.001” TIR. Torque the brake ring mounting bolts per Haas torque chart

B Axis Platter Installation

1

Coat the brake ring OD surface with the 5% MOBIL MOLY GREASE (99-1792)

Installing the B axis platter, leave the mounting bolts hand tight.

Connect all of the brake booster and hydraulic fittings and Refer to UMC-500/750/1000 Rotary Brake Bleed - AD0496 to bleed the B axis brake

2

Clamp the B axis brake (This will center the B axis platter over the brake ring) and gradually torque the B axis platter mounting bolts. Refer to Haas torque chart

Verify the run out of the ID of the B axis platter center bore once the bolts are torqued. This is N.T.E. 0.0015".

Note: Record the final value in Setting 254 5-Axis Rotary Center Distance. Depending on the indicator set up, Setting 254 may need to be set to Zero to prevent false readings.

Rotate the B axis over the full travel. Observe the servo load (spikes would indicate that the brake ring is dragging). Listen if there is any abnormal noises from the brake area as the B axis rotates.

C axis Installation

Requirement: Verify machine is equipped with Brake Regulators. Reference the following AD documents: UMC Brake Booster Regulator Service Kit - AD0601

1

Use the eye bolt installed on T-2194A to hoist the C-Axis with a forklift or crane.

2

Reinstall the C axis to the B axis and install the top 4 bolts

3

Remove T-2194A and install the 4 bolts

4

Install remaining 4 bolts under the C AXIS BODY. Be sure to torque all bolts.

Refer to Haas torque chart

5

Install the brass center plug into the B axis platter.

Warning : Verify B axis brake bleeding procedure is complete before installing plugs.

6

Install all plugs into the C axis body.

7

Connect all the cables and hydraulic lines to the C axis. Re-install the Rotary Front Support.

UMC - B Axis Brake Replacement - AD0474