Gradall LOED 534A Service Manual - Manual (Page 83)

BEARING REPLACEMENT
MOBIL-MASTER SERIES 20 & 25
INSPECTION OF PARTS
BEARING REPLACEMENT-INSPECTION OF PARTS
83
Mobil-Master Series 20 and 25 Pumps are
built with the highest capacity bearings
available. However, if the pump is run on
a system with contaminant present in the
oil, or under certain other conditions, bear-
ing failure may be experienced. In the
event of bearing failure the bearings may be
replaced if the gears have not cut a track
in the housing deeper than .015 inches.
To remove the old bearings, disassemble
the pump and place the body in a vise.
Clamp on the sides of the body using card-
board to prevent marring by the vise jaws.
Using the small keyhole type hack saw, cut
through the bearing opposite the oil groove.
Be sure the saw cuts completely through the
bearing shell, but cuts as little as possible
into the aluminum bore.
After the cut is made, grip the bearing with
vise-grip pliers and remove with a twisting
motion (body bearings). Flange bearings
can be wedged out with a screw driver.
Take care not to damage the bores. After
removal, wash the parts thoroughly in sol-
vent. Press in the body bearings so that
they protrude above the surface . 220/. 230.
Press flange bearings in . 090 below surface.
The split in the bearing goes in the same
location as was the oil groove in the bronze
bearings.
Install the remaining parts of the repair kit
and replace on the machine. No break-in
is necessary and the unit is ready to operate
at full capacity.
Visually inspect all parte. There will
be a gear track on the inside of the
pump body. Measure the depth of this
gear track. If the groove is deeper than
.005 (five thousandths) of an inch, the
body should be rejected for further use.
If the track is less than .005, the body
is all right for reassembly provided it
is not cracked or damaged otherwise.
E xamine the pressure plates. They should
not show excessive wear on the bronze
side. If deep curved wear marks are
visible, reject them.
Examine the gears. If excessive wear
is visible on the journals, sides or face
of the gears, or at the point where it
rotates in the seal, reject them.
If any of the internal parts show exces-
sive wear, replace all the parts with
the cartridge kit.
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