Gardner Denver GAF P Series, Operating And Service Manual

Page: 31 / 40

SB-7-622 Page 30
NOTICE
Replacement gears have minimum backlash marks on the outside diameter of the gear face.
These marks should be located 180 degrees from each other (see Figure 7-6)..
F. Position impellers so they are 90 degrees to each other. Using the driving tool shown on page 22, install the
gears and hubs on the shafts using the taper pin holes and match marks for correct positioning. Check to be sure
impellers are in correct position as previously match marked.
NOTICE
Utilize a press whenever possible when installing gears.
G. Refer to diagram in Figure 7-4, page 31. Use feeler gauges to check clearances between impeller lobes at
A-A and C-C. Add the clearances, and divide the total clearance evenly between A-A and C-C.
H. Loosen the four capscrews (38) in one gear only. Wedge the correct amount of feeler gauge between
impeller at A-A. If movement between the gear and hub is not sufficient to time the impellers, it will be necessary
to loosen the four capscrews (38) in the mating gear to obtain a large adjustment range. Adjust so that the
clearance at A-A is equal to C-C within .001 inch.
Clearances must be checked on both sides of each impeller lobe over the entire length. This procedure may
require repeating several times until impeller lobe clearance is equal on both sides.
I. Secure the timing gears (9) to hubs (39) with capscrews (38) and lockwasher (37). Tighten capscrews to the
torque specification listed in Figure 7-6, page 35.
J. Check gear backlash four places at 90 degree intervals as described in the disassembly procedure (Item 4).
NOTICE
If any of the four gear backlash readings are not within the specified limits, the gears must be
replaced.
K. Reream taper pin hole between the shaft and hub with a hand reamer and replace taper pin (8) if movement
between the shaft and hub (39) was negligible. If rereaming fails to eliminate edges due to slight misalignment,
drill and ream a new hole approximately 90 degrees from the original hole. Control the depth of the taper pin,
leaving approximately 1/8
” taper pin protruding beyond the hub and shaft.
L. Reream center drilled hole in the hub and gear web. If rereaming fails to eliminate edges set up by retiming,
ream hole for the next larger taper pin or drill and ream a new hole approximately 90 degrees from the original
hole. Control the depth of the threaded taper pin (36), leaving the threaded portion of the pin protruded beyond
the hub.
Replacement gears are not drilled for taper pin (8). These holes must be drilled and reamed after the gears
are in proper position and the unit retimed.
NOTICE
Be careful not to allow cuttings to drop behind the gears and contaminate the bearings.
M. Remove paper from behind the gears. Make certain metal cuttings did not contaminate the bearings.
18 Assemble gear cover (3) and gasket (7) to the gear headplate (18) using capscrew (5). Tighten capscrews
alternately and evenly. Refer to Figure 7-6, page 35 for torque specifications.
19 Place blower on its feet on a flat surface. Loosen capscrews (16) and level unit up. The bench or blower
base flatness should be within .002 of an inch. Re-tighten capscrews (16) to the specifications in Figure 7-6,
page 35.