Figure 7-1 - Rotor Shaft Seal; Figure 7-2 - Bearing Spacer; Figure 7-3 - Discharge Opening; Figure 7-4 - Rotors - GD P Series Parts List Operating And Service Manual

2. To ease assembly in later steps, fit the bearing spacers (16, 17) to the seals (18, 19)
(FIGURE 7-2, page 41). Be sure there are no burrs on the spacer O.D. and seal I.D. Spacer
should be SLIP FIT in the seal. A sloppy fit will cause excess air leakage and decrease blower
efficiency. Do not drive the spacer through the seal as damage to the babbitt will result. It may be
necessary to polish the high spots from the seal I.D. to allow slip fit of the spacer. USE CROCUS
CLOTH, not emery cloth.
Never push the grooved end of the spacer through the bearing oil seal as the lip of the seal may
be damaged. Apply Loctite 620 to the ID of the bearing spacer. When the spacers are fitted,
slide them on the gear end shaft extension of the rotors with the grooved end toward the rotor.
Make sure there are no burrs on either end of the spacer or end of the rotor. Place tape around
the shaft to prevent the spacer from sliding off as shown in (Figure 7-4, page 41).
FIGURE 7-1 – ROTOR SHAFT SEAL
3. Place .030" thick aluminum shim (20) on the gear end bearing carrier (4). The pointed section of
the shim is positioned on the machined surface of the carrier to match the contour of the housing.
Lower the housing (1), as level as possible, onto the carrier with the discharge opening up (Figure
7-3), and the inlet opening matching the cavity side (FIGURE 7-1, page 41), of the carrier. Engage
the dowel pins (57) with matching holes in the carrier with care. Tighten the carrier to housing
screws (47, 59) evenly so the dowel pins will not be damaged.
4. Be sure the ends of the rotors (2, 3) and machined face of the carrier are free of burrs and dirt.
Lower the gate rotor (3) into the housing (1) first (Figure 7-4). The gear end shaft extension, with
the bearing must be suspended plum when lowering so the shaft extension and bearing spacer
can be carefully guided through the close fit of the shaft seal without damage to the babbit of the
air seal. On older models, match timing marks on the end of the rotor lobes as shown in
(FIGURE 7- 9, page 43). Rotors must be used in matched pairs. Identifying marks are stamped
on the O.D. of the rotors on the same lobe as the timing marks.
FIGURE 7-3 – DISCHARGE OPENING
FIGURE 7-2 – BEARING SPACER
37-1-614 Page 41
FIGURE 7-4 – ROTORS