
CLICK on product numbers
above to obtain the product detail
sheet which includes dimensional
data helpful during installation.
Installation & Maintenance Manual
NEMA FRAME SPRING ENGAGED FRICTION BRAKES
Catalog Products:
D3C3R-56H , D3C3R-56HCA & D3C3R-56HSS
D3C3R-14H , D3C3R-14HCA & D3C3R-14HSS
D5C3R-18H , D5C3R-18HCA & D5C3R-18HSS
D5C3R-21H , D5C3R-21HCA & D5C3R-21HSS
And non-catalog variations of this brake design.
Mach III Technical Support
Toll Free: 866-291-0849
International: 001-859-291-0849
Email: engineering@machiii.com
www.machiii.com
Detail sheets and 3D models are available on the Mach III website:
http://www.machiii.com/Products/Brakes/Spring-Set-Brakes/NEMA-Frame-Spring-Set-
Brakes-C-Face-Mount.asp
Please contact Mach III to obtain assembly and parts list drawings.
This product includes rotating equipment and should be guarded according to
OSHA requirements and other Federal, State and local regulations. It is the
responsibility of the user to provide necessary guarding.
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© Mach III Clutch, Inc. All Rights Reserved

I. New Brake Torque
New brake torque is approximately 40% less than rated design torque until the friction
and drive discs are worn in (lapped, burnished). The length of time for wear-in to occur
depends upon the application.
II. Brake Installation
A. SHAFT PREPARATION
Mach III Clutch products are bored to fit a precision plug gauge for the specified bore size and
should slide fit the mating shaft. Make certain that the shaft is free of burrs or nicks. It may be
necessary to file or sand the shaft to assure a slide fit. Never hammer the brake onto the
shaft. Hammering on the brake may cause evident damage or subtle injury that will shorten the
wear life of the unit, and will void the warranty.
(1) Apply the anti-seize (E-Z Break®) lubricant from the packet provided, or equivalent, to
the shaft.
(2) Insert key (customer supplied) onto the shaft.
(3) Slide brake over key on the shaft.
B. MOUNTING
The brake mounts between a motor and gear reducer. These units are not suitable for belt drive
(pulley output) applications. Consult factory for options.
C. AIR LINE CONNECTION
Refer to the dimensional spec sheet for NPT size to obtain correct fitting. Install fitting using a
thread sealing compound to prevent air leakage. Connect an air line to the fitting. Air supply
should be both filtered and regulated. Contamination in the air supply may damage the brake.
D. FINAL INSPECTION & TESTING
Cycle the brake with the machine off to check for air leaks and to ensure proper engagement and
release. After a short run, check mounting screws.
III. Brake Operation
This brake is spring engaged (air released). The air pressure required to release the
brake is between 60 and 70 PSI. For maximum life of the brake, air pressure should not
exceed 80 PSI.
Special Note Regarding Friction Disc Contamination:
The friction material used in this product will absorb oil, water, chemicals and other
contaminants. Depending on the type of contamination, brake may either seize up
entirely or lose torque capacity. If friction discs become contaminated, they should be
replaced. See repair kit ordering information below. If application requires exposure to
contamination consult factory for optional covers.
IV. Routine Maintenance
When installed and operated according to the preceding guidelines, Mach III clutch
products should require little or no routine maintenance. A repair kit is available which
contains all parts subject to typical wear: friction discs, springs and O-rings.
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V. Parts diagram
Part number = Brake Product Number + “-RPRK” (e.g. D3C3R-56H-RPRK)
Contact Mach III to obtain a complete listing of additional parts kits available for
your specific brake. Please reference product number when calling or e-mailing.
Factory repair is available. A return materials authorization (RMA) number must
be obtained prior to sending any unit in for repair
Tools Required
Hex Wrench Set
Rubber Mallet or similar soft face hammer
Retainer (snap) Ring Pliers
Scraper
Compounds Required
Grease
O-ring Lubricant
Loctite® #609 Retaining Compound
Anti-Seize Lubricant (for re-installation)
DRIVE HUB
CYLINDER
PISTON
BEARING
RETAINER RING
O-RING
FRICTION DISC
DRIVE DISC
SPRING
SCREW WITH SPACER
TOP PLATE
PRESSURE PLATE
RETAINER RING
RELEASE SPRINGS
RACE
VI. Repair Kit Installation Procedure
A. COMPLETE DISASSEMBLY
(1) Remove brake from shaft and place in vertical position with top plate end facing
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upward.
(2) Apply air to brake to relieve spring pressure from top plate.
(3) Remove retainer ring.
(4) Remove top plate.
(5) Remove retainer ring and race over release springs.
(6) Remove drive discs, friction discs and springs.
(7) Remove air supply from brake.
(8) Invert brake and remove retainer ring from drive hub.
(9) Remove air cylinder with bearing from drive hub. The air cylinder bearing is a slide fit
on the drive hub and is affixed to the drive hub with a thin coating of Loctite
need to strike the hub, or an object inserted in the hub with a rubber mallet or similar
soft face hammer to break the Loctite® seal.
(10) Next, remove the screws from pressure plate.
(11) Remove spacers and springs.
(12) Separate piston from cylinder.
®.
You may

B. FRICTION DISC REPLACEMENT ONLY
(1) Remove brake from shaft and place in vertical position with top plate end facing
upward.
(2) Apply air to brake to relieve spring pressure from top plate.
(3) Remove retainer ring and top plate.
(4) Remove retainer ring, race and release springs.
(5) Remove drive discs, friction discs and springs.
(6) Drive discs should be clean, dry and free of burrs or nicks.
(7) Reassemble drive disc, friction disc, springs using new friction discs, steel drive discs
and springs as necessary.
(8) Assure that drive discs move freely on the drive hub and that the friction discs move
freely in the cylinder or ring gear.
C. O-RING REPLACEMENT
(1) Follow COMPLETE DISASSEMBLY instructions above.
(2) Separate cylinder and piston.
(3) Inspect O-ring seals. If worn, replace using new O-rings that have been lubricated with
an O-ring lubricant such as Dow Corning® #4 Compound or equivalent.
(4) A very thin coat of O-ring lubricant should also be applied to the inner walls of the
cylinder.
D. REASSEMBLY
(1) Replace the piston in the cylinder.
(2) Make sure the tapped holes in the piston are aligned with corresponding holes in the
cylinder.
(3) Replace the spacers and springs.
(4) Replace the pressure plate and screws making sure screws are tightened to uniform
torque based on bolt size and use proper Loctite® (or equivalent) compound to assure a
permanent mount.
(5) Inspect the inside diameter of the bearing in the air cylinder. If Loctite® residue is
present, gently scrape and assure that the surface is clean.
(6) Apply a thin coat of Loctite® #609 retainer compound to the inside diameter of the air
cylinder bearing, then slide the air cylinder/bearing sub-assembly over the drive hub.
Applying excessive Loctite® will make future disassembly more difficult.
(7) Make sure that all components are well seated and replace the outer retainer ring.
(8) Reassemble drive, friction disc, and springs using new friction discs, springs and steel
drive discs as necessary.
(9) Apply air to the brake.
(10) Replace top plate and retainer ring.
(11) See “Brake Installation” portion of these instructions for the proper procedure for
reinstalling the brake.
Technical assistance is available by contacting Mach III Clutch, Inc.
Mach III Product Warranty
http://www.machiii.com/Resources/Warranty-Info.asp
Mach III Clutch, Inc.
101 Cummings Drive ● Walton, KY 41094
Toll free 866.291.0849 ● International 859.291.0849 ● Fax 859.655.8362
info@machiii.com ● engineering@machiii.com ● www.machiii.com
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