Mach III Clutch 98BK & 98BK-ULOW - Manual (Page 4)

7/10/2013 BRAKES_SENSIFLEX_BK_MANUAL Page 4 of 5
IV. Repair Procedure
Tools Needed
Hex wrench set
Spanner wrench
Retainer (snap) ring pliers
Flat head screw driver
Scraper (if replacing bearings)
0.010 Inch feeler gauge Compounds Required
Grease
O-Ring lubricant
Loctite® #609 Retaining Compound
Anti-Seize Lubricant
A. Friction Disc Replacement
Loosen set screws and bolts from flange and slide the brake off of the shaft. Place brake in a
horizontal position with the cylinder facing downward. Loosen nylon point set screw in retainer
nut. Using a spanner wrench remove the retainer nut. Next, remove drive disc which should slide
easily off of drive hub. Inspect the drive surface which contacts the friction disc. Grooves in the
surface would indicate that the friction disc should have been replaced sooner and the heads of the
mounting screws have made contact. This surface must be free from grooves, burrs and foreign
materials in order for the brake to operate properly. If damage is pronounced, please contact Mach
III Clutch or your distributor for a replacement. In addition, the drive disc surface should be
inspected for discoloration (turning blue). If discoloration is present, the unit is being operated
beyond its capacity and Mach III Clutch should be contacted for assistance. To replace the friction
disc, remove brass screws which affix the disc to the piston. Remove the worn friction disc and
make sure the mounting surface is smooth and free from contamination. Mount new friction disc
by snugging all screws using an alternating sequence. Do not over-tighten. If no other
components require replacement, skip to section 3b (Reassembly) for the proper procedure for
reassembling the brake.
B. Diaphragm and/or Bearing Replacement
Diaphragm replacement should rarely be necessary if the air supply is regulated and free of
contamination and if the gap between the friction and drive disc is properly set. Care should be taken
when mounting the brake to insure maximum bearing life. See “Shaft Preparation & Mounting”
for guidelines
1. Diaphragm Replacement
First, follow disassembly instructions above under Procedure for Friction Disc Replacement.
Friction disc can remain mounted on piston during this procedure. Wave spring should be
removed and set aside. Next, turn assembly so that the retainer rings in the air cylinder end are
accessible. Remove innermost retainer ring. Bearing ID is a slide fit on the hub and is affixed to
the hub with a thin coating of Loctite®. You will need to strike the hub or an object inserted into
the hub with a rubber mallet or similar soft face hammer while pulling the cylinder upwards to
break the Loctite® seal. Once seal is broken, remove hub from assembly.
To gain access to the diaphragm remove stud & coil springs, then separate the air cylinder and
piston. Pinch the diaphragm and pull from the grooves which retain it. Make sure that the
retaining grooves and surface underneath the diaphragm are clean & free from debris.
Lubricate the new diaphragm with an O-ring lubricant such as Dow Corning® #4. Install with the
lips located on the ID and OD of the diaphragm facing downward. Press the lips into the grooves