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This procedure tells you how to replace the brake booster assembly on the B- and C-Axis rotary systems. The kit includes 3/8" hoses, which replace the 1/4" hoses on the machine, and improve performance of the brake system.

This booster assembly has:

• Oil reservoir fitting [1].
• Brake Engage port [2].
• Brake Booster Retract port [3].

Machine Compatibility

EC-1600, UMC-750/P/SS, UMC-500/SS and UMC-1000/SS machines.

• KIT: 93-30-11839 BRAKE BOOSTER ASSEMBLY, HYDRAULIC

Caution: Before working on the hydraulic brakes on the below listed machines turn the machine OFF, disconnect the air supply and drain the hydraulic brake fluid from the oil reservoir that is connected to the brake booster.

Disconnect the Brake Engage air line [5].

Remove and discard the 1/4" oil line [6].

Remove and discard the 1/4" fitting [1] from the bottom of the oil reservoir.

Disconnect the rotary brake hydraulic hose [2].

Remove the tee fitting [3] with the pressure sensor.

Remove two mounting bolts.

Remove the old brake booster.

Remove the straight brass fitting [1] from the new hydraulic booster assembly.

Install the 90 degree 3/8 compression fittings [2] on the bottom of the oil reservoir and onto the oil inlet on top of the booster.

Connect the oil reservoir to the oil inlet on top of the booster with the 3/8" hose [3].

Connect the Brake Engage air line to the Brake Engage port [4].

Connect the Brake Booster Retract air line to the Brake Booster Retract port [5]. 

 NOTE: If the machine does not have the Hydraulic Brake Booster Retract air line refer to the Rotary - Hydraulic Brake Booster Retract Air Line - Installation.

Install the tee fitting with the pressure sensor [6].

Bleed the air out of the brake system. Refer to the Rotary Brake - Bleed Instructions - EC-1600

Disconnect the Brake Engage air line [1].

Disconnect the tee fitting [2] with the pressure sensor on it.

Remove two bolts [3] that secure the brake booster to the mounting bracket.

Remove the the oil reservoir [4].

Remove the  brake booster [5].  

Thread the oil reservoir [1] onto the oil inlet fitting on the new brake booster.

Connect the tee fitting [2] with the pressure sensor to the oil outlet port.

Secure the brake booster to the mounting bracket with the SHCS.

Connect the Brake Engage air line to the Brake Engage port [3].

Connect the Brake Booster Retract air line to the Brake Booster Retract port [4]. 

 NOTE: If the machine does not have the Hydraulic Brake Booster Retract air line refer to the Rotary - Hydraulic Brake Booster Retract Air Line - Installation.  

Bleed the air out of the brake system. Refer to the Rotary Brake - Bleed Instructions - EC-1600.

Remove and discard:

• 1/4" hose [1] between the oil reservoir and the brake booster.
• 1/4" fitting [2] from the bottom of the oil reservoir.

Disconnect the Brake Engage air line [3].

Remove the four bolts [4] that secure the brake booster to the rotary body.

Remove the old brake booster. 

NOTE: There is an o-ring [5] between the face of the brake booster and the rotary body. You will reuse this o-ring when installing the new brake booster.

Remove the straight fitting [1] from the oil inlet on the brake booster.

Install the 3/8" compression fittings [2] on the bottom of the oil reservoir and onto the oil inlet of the brake booster.

Place the o-ring [3] in the groove on the face of the brake booster.

Attach the brake booster to the rotary body with four mounting bolts [4].

Route the 3/8" hose [5] from the oil reservoir to the oil inlet on the brake booster.

Connect the Brake Engage air line [6].

Connect the Brake Booster Retract air line [7]. 

 NOTE: If the machine does not have the Hydraulic Brake Booster Retract air line refer to the Rotary - Hydraulic Brake Booster Retract Air Line - Installation.  

Bleed the air out of the brake system. Refer to the B-Axis and C-Axis Rotary Brakes - T-0062C Bleed Instructions - UMC-750/P/SS .

Disconnect the Brake Engage air line [1]. 

Remove the four bolts [2] that secure the brake booster to the rotary body.

Remove the oil reservoir [3].

Remove the old brake booster. 

 NOTE: There is an o-ring [4] between the face of the brake booster and the rotary body. You will reuse this o-ring when installing the new brake booster.

Thread the oil reservoir [1] onto the oil inlet fitting on the new brake booster.

Place the o-ring [2] in the groove on the face of the brake booster.

Attach the brake booster to the rotary body with four mounting bolts [3].

Connect the Brake Engage air line [4].

Connect the Brake Booster Retract air line [5]. 

 NOTE: If the machine does not have the Hydraulic Brake Booster Retract air line refer to the Rotary - Hydraulic Brake Booster Retract Air Line - Installation.  

Bleed the air out of the brake system. Refer to the B-Axis and C-Axis Rotary Brakes - T-0062C Bleed Instructions - UMC-750/P/SS .

NOTE: C axis brake booster replacement is shown in this step. The B axis booster replacement is identical.

Disconnect the Brake Engage air line [1].

Remove and discard the 1/4" oil lines [2].

Remove and discard the 1/4" compression fittings [3].

Disconnect the tee fitting [4] with the pressure sensor on it.

Remove the air regulator assembly [5]

Remove two mounting bolts [6].

Remove the old brake booster assembly. 

Install the tee fitting [1] with the pressure sensor onto the brake booster oil outlet and connect the rotary brake line.

Secure the new brake booster to the mounting bracket with two mounting bolts [2].

Install the 3/8" compression fittings [3].

Route the 3/8" oil lines [4] from the oil reservoir to the brake booster.

Install the air regulator assembly [5] onto the Brake Engage port and connect the Brake Engage air line [6].

Connect the Brake Booster Retract air line [7]. 

 NOTE: If the machine does not have the Hydraulic Brake Booster Retract air line refer to the Rotary - Hydraulic Brake Booster Retract Air Line - Installation.  

Bleed the air out of the brake system. Refer to the B-Axis and C-Axis Rotary Brakes - T-0062C Bleed Instructions - UMC-750/P/SS .

 NOTE: This section shows how to replace the C axis brake booster on the UMC-1000 rotary. The same procedure applies to the UMC-1000SS, UMC-500, UMC-500SS and the UMC-750SS that was built after the April 2017.

Remove the tee fitting [1] with the pressure sensor.

Disconnect the Brake Engage air line [2].

Disconnect the Brake Booster Retract air line [3].

Remove two mounting bolts [4].

Remove the old booster [6] from the machine.

Remove the oil reservoir [7].

Install the new brake booster in reverse order. 

 NOTE: UMC-750SS machines require the air pressure regulator on the Brake Engage port. Install the air pressure regulator assembly from the old brake booster onto the new one before connecting the Brake Engage air line. Failure to do so will cause the damage to the rotary brake system. Refer to the section above.

Bleed the air out of the brake system.