Graco 3900 Paint Sprayer User Manual


 
3094098
Bearing Housing and Connecting Rod
NOTE: The item numbers referenced are for the
Hi-Boy models. The Lo-Boy models may have different
item numbers. Use the Hi-Boy item number and part to
find the corresponding Lo-Boy part and item number.
Removal
1.
Relieve pressure; page 5.
2. Fig. 2. Remove screws (14) and front cover (23).
3. For Hi-Boy models; remove spring clip (32) and
drain hose (54). Unscrew suction tube (30) from
pump, hold wrench on pump intake valve (A) to
keep pump from loosening. For Lo-Boy models;
unscrew swivel union (30aa) from pump.
4. Disconnect pump outlet hose (33) from displace-
ment pump outlet nipple (62).
5. Fig. 1. Use screwdriver to push up retaining spring
(26) at top of pump. Push out pin (29).
Fig. 1
7675B
29
26
6. Fig. 2. Loosen retaining nut (34). Unscrew and
remove displacement pump (28).
7. Remove four screws (13) and lockwashers (12)
from bearing housing (21).
8. Pull connecting rod (22) and lightly tap lower rear
of bearing housing (21) with plastic mallet to
loosen from drive housing (20). Pull bearing hous-
ing and connecting rod assembly (22) off drive
housing.
9. Inspect crank (B) for excessive wear and replace
parts as needed.
Installation
1. Evenly lubricate inside of bronze bearing (C) in
bearing housing (21) with high-quality motor oil.
Liberally pack top roller bearing (E), lower bearing
(D) inside connecting rod assembly (22) with
bearing grease.
2. Assemble connecting rod (22) and bearing housing
(21).
3. Clean mating surfaces of bearing and drive hous-
ings.
4. Align connecting rod with crank (B) and carefully
align locating pins (F) in drive housing (20) with
holes in bearing housing (21). Push bearing hous-
ing onto drive housing or tap into place with plastic
mallet.
CAUTION
DO NOT use bearing housing screws (13) to align
or seat bearing housing with drive housing. Align
these parts with locating pins (F), to avoid prema-
ture bearing wear.
5. Install screws (13) and lockwashers (12) on bear-
ing housing. Torque evenly to note 3 value in Fig. 2.
6. Refer to Displacement Pump, Installation, page 17.
8697B
21
12, 13
14
26
29
28
B
GMax 3900: Torque to 200 in-lb (22.6 Nm)
33
34
22
C
E
62
Pack with bearing grease 114819
Oil
54
A
F
30
32
3
2
1
1
2
3
Fig. 2
Model 233701 shown
23
8697A
20
D
2
GMax 5900: Torque to 25 ft-lb (34 Nm)