MDX [en-US]
30
The drive end radial bearing next to the thrust bearing should be mounted with its inner race in direct contact with the
split ring (or split thrust collar). If it is a taper lock type, first position it on the shaft while loosely mounted on its adapter.
The locknut should then be tightened until the internal bearing clearance as determined with a feeler gauge is equal to
the actual un-mounted clearance minus the required decrease as specified in the chart above. The locknut must then
be locked in position by bending one tab of the lock washer into one of the recesses on the locknut. Be sure that the
radial bearing inner race is still in contact with the split ring (or split thrust collar).
The spring retainer ring should be placed loosely on the shaft from the threaded end of the shaft with the spring holes
facing the thrust bearing. If the housing is a PB type (“pillow block” construction with separate housings for drive and
pump end bearings) then also install the two labyrinth oil seals with their internal flingers, springs, o-rings and v-rings
on the shaft at this time. Make sure that the seals are in the proper direction
The remaining pump end radial bearing should be mounted last. If it is of the taper lock type, ensure that its position
after assembly will be 1/4" to 5/16” (6 to 8 mm) from the housing end cover.
Split Thrust Collar
Sizes 2-15/16 to 4-7/16
Split Ring and Thrust Collar
Sizes 5-7/16 and larger
Mid-shaft seal arrangement with PB housings
8.3.2
Closing the Housing
Limited End Float (LEF) bearing assemblies require an additional shimming procedure to ensure proper operation. The
correct number of shims needed is determined prior to closing the housing and installing the end covers with the
following procedure:
o
Install the shaft with mounted bearings and spring retainer ring (472) into the housing base (351), but without
the springs (950.71) installed.
o
With the bearing housing cap (351) off and without the shims (89-4.71/.72), install the bearing end cover
(361.70) and tighten the lower bolts (901.70) until all internal bearing clearance is eliminated and the end
cover contacts the taper roller bearind. A gap should remain between the end cover and housing.
o
Dowel and bolt the housing cap to the base and install the remaining end cover bolts.
o
Measure the maximum gap between end cover and housing with a feeler gauge.
o
Select enough 0.010” (0.25mm) shims (and 0.005” / 0.13mm if included in your bill of materials) to fill this gap
plus 0.002” to 0.010” (0.05mm to 0.25mm) extra interference. These will be used when installing the bearing
end cover.
o
Unbolt the end cover and housing cap from the base. Remove the shaft with mounted bearings and spring
retainer ring from the base and re-assemble using remaining steps.
Insert the thrust bearing springs into the retainer ring. A small amount of grease can be used to hold springs in place.
Place the shaft and bearings into the housing lower half. Be sure that the thrust bearing outer race and springs are held
in their proper place.
Place the lockwashers on the bolts and lightly coat the threads with anti-seize.
Slide the end covers and gaskets on the shaft.
Apply an 1/8" (3mm) bead of RTV (Room Temperature Vulcanization) silicone sealant along the bottom half, between
inside edge and the bolt holes. Run the silicone bead into the end cover area.
Lower the top half and install the dowel pins.
Tighten the housing bolts, working from the center out and alternating side to side. Final torque should be verified as
75% of yield for lubricated Grade 5 or Metric 8.8 fasteners.
For pillow block assemblies, this torque is very important for proper bearing fit. These housings are torqued in a cross
or "X" pattern.
Where a dowel pin has internal threads for removal, protect the threads with RTV silicone or install a matching screw.
Summary of Contents for GIW MDX
Page 53: ...MDX en US 53 14 Notes...
