Eaton 70122 User manual

Eaton®
Medium Duty Piston Pump
Model 70122, 0 -19 cm3/r [0-1.16 in3/r] Displacement
Pressure or Pressure-Flow Compensated Piston Pumps
Parts and Repair
Information
January 1998

2
Model 70122
Table of Contents
Introduction.........................................................................................................2
Identification........................................................................................................3
Tools Required ....................................................................................................3
Parts Drawing......................................................................................................4
Parts List .............................................................................................................5 -12
Item 1 - Drive Shaft ID ..................................................................................6
item 2 - Backplate Assembly .........................................................................7
Item 4 - Compensator Assembly and Parts List ............................................8 -9
Factory Pre-set Compensator Assemblies.....................................................10
Item 5 - Rotating Kit......................................................................................11
Product Number............................................................................................12
Repair information...............................................................................................13 - 15
Disassembly..................................................................................................13
Inspection .....................................................................................................14
Reassembly...................................................................................................15
Start-up Procedure ..............................................................................................16
Fault-Logic Troubleshooting................................................................................17 - 19
Introduction
This manual provides service information for the Eaton Models 70122 Pressure or Pressure - Flow
Compensated Piston Pumps. Step by step instructions for the complete disassembly, inspection, and
reassembly of the pump are given. The following recommendations should be followed to insure successful
repairs.
Remove the pump from the application.
Cleanliness is extremely important.
Clean the port areas thoroughly before disconnecting the hydraulic lines.
Plug the pump ports and cover the open hydraulic lines immediately after they're disconnected.
Drain the oil and clean the exterior of the pump before making repairs.
Wash all metal parts in clean solvent.
Use compressed air to dry the parts. Do not wipe them dry with paper towels or cloth.
The compressed air should be filtered and moisture free.
Always use new seals when reassembling hydraulic pumps.
Lubricate the new rubber seals with a petroleum jelly (Vaseline) before installation.
Torque all bolts over gasketed joints, then repeat the torquing sequence to make-up for gasket
compression.
Verifying the accuracy of pump repairs on an authorized test stand is essential.
Introduction

3
Model 70122
Year Manufactured
(1 for 1991 etc.)
Change Code
Identification Numbers - Pressure or Pressure-Flow Compensated Piston Pump
Stamped on each units mounting flange.
A - Product Number Description
70122 = Single Piston Pump
B - Rotation
L - Lefthand (CCW)
R - Righthand (CW)
C - Sequential Numbering
Single Pump - Product Number:
7 0 1 2 2 - R A A
A
Serial Number Code:
B 93 01 31 JB Testers Initials
Day of Month (two digits)
Month (two digits)
Revision level of parts list.
Last two digits of year built.
( 93 for 1993 etc.)
BC
Serial Number Code prior to Jan., 1992:
1 B- 52-JB Testers Initials
Week of Year
Identification and Tools Required
•1/2 Inch Socket
•1-1/8 Inch End Wrench
•11/16 Inch End Wrench
•Rachet Wrench
•Torque Wrench (100 lb./ft.)
•3/16 Inch Hex Key (Allen)
•3/16 Inch Hex Key (Allen Socket)
•Soft Face Hammer
•Internal Retaining Pliers (Straight .070 Tip)
•External Retaining Pliers (Straight .070 Tip)
•Regular or Locking Pliers
•Seal Driver or Similar Tool
•Petroleum Jelly (Such as Vaseline)
•5/16 I.D. x 15/16 O.D. flat washer (2 ea.)
•5/16 x 2-7/8 N.C. Cap screw (1 ea.)
•5/16 N.C. Nut
Tools Required

4
Model 70122
Parts
Drawing
Pump drawn below is typical of a righthand rotation pump.
1
32
3
3-1
10
16
1615
10
13
17
12
25 19 26 20 11
11 20 26 19 25
18
22 23
96
5
21 7
2
24 27
28
414
Serial code and
assembly number location
8
(
Cover only)
3-2
All left (CCW) or right (CW) directions
given are viewed from the input shaft end of the pump.

5
Model 70122
Parts List
Item Part No. Qty. Description
1♦1 Drive Shaft (Identification drawing on page #6)
2♦1 Backplate Assembly (Identification drawing on page #7)
3 70102-301 1 Housing Assembly, .5625-18 - SAE Straight Thread O-ring Port - Right side of housing
3-1 16238-11616 1 Bearing
3-2 16026-608 2 Roll Pin
4♦1 Compensator Assembly (Identification drawing on page #8, 9 & 10)
5♦1 Rotating Kit Assembly (parts list on page #11)
6 70120-602 1 Camplate
7 70120-401 1 Control Piston
8 70422-618 2 Cover
9 16026-507 1 Roll Pin
+ 10 16078-16 2 Retaining Ring
+ 11 16077-24 2 Retaining Ring
+ 12 16077-26 1 Retaining Ring
13 16048-312 1 Washer
14 16148-412 4 Cap Screws
15 16241-1625 1 Thrust Bearing
16 16241-C1625 2 Bearing Race
+ 17 16253-16 1 Shaft Seal
17 16253-216 1 Shaft Seal, Drive (fluorocarbon rubber)
18 17073-6 1 Spring
19 70101-150 2 Inner Race
20 70111-622 2 Trunnion Cover
+ 21 70111-701 1 Gasket
22 70120-600 1 Spring Collar
23 70120-601 1 Button
+ 24 70422-600 1 Gasket
25 76100-191 2 Thrust Bearing
+ 26 16015-25 2 O-ring, 3/32 x 1-5/16 ID
27 16032-512 4 Cap Screw
+ 28 16003-5-90 1 O-ring, 1/16 x 1/4 ID 90 DUR
32 16246-427 1 Key, Used on 19.05 [.75] diameter shaft
32 24500-619 1 Key, Used on 22.2 [.875] diameter shaft
Seal Repair Kit
• 70122-902 1 Seal Repair Kit
Legend ♦Refer to specific item parts list.
+ Included in seal repair kits listed.

6
Model 70122
70122-203,
22.2 [.875] Dia. keyed
70102-200, 13 Tooth
70122-200,
19.05 [.75] Dia. keyed
70102-201, 13 Tooth
w/ Retaining Ring Groove
Item 1 - Drive Shaft Identification
Item 1
Drive Shaft Identification
Part Number Input Drive

7
Model 70122
2-1 2(a)
2-2
2-2-1
2(b)
2-3
(Loctited)
Lefthand Rotation
(CCW) Righthand Rotation
(
CW
)
Item 2 - Backplate Assembly
Item 2 - Parts List
Lefthand Righthand
Rotation Rotation
Item Part No. Part No. Qty. Description
2(a) 70120-311 70120-309 1 Rear Porting Backplate Assembly
2(b) 70120-314 70120-318 1 Opposite Side Porting Backplate Assembly
2-170420-43 1 Bearing
2-216103-103 2 Plug Assembly
+ 2-2-116133-3 2 O-ring, 1.59 mm Dia. x 7.54 mm I.D.
[.0625 in. Dia. x .2969 in. I.D.]
2-370120-400 1 Guide Pin
Legend + Included in seal repair kit listed on page 5.
All left (CCW) or right (CW) directions
given are viewed from the input shaft end of the pump.

8
Model 70122
4-1
4-2 4-3 4-4
4-6
4-5
4-7 4-8
4-94-104-11
4-94-10
4-11
4-12 4-13
4-14
4-15
4-16
4-174-18
4-19-1
4-19
Lefthand (CCW) Pump Rotation Righthand (CW) Pump Rotation Fits Both Pump Rotations
(Righthand (CW) rotation shown)
Pressure-Flow Compensator Pressure Compensator
4(a) 70422-HU 4(b) 70422-HY 4(c) 70422-HR
*4-11, Cover not included with non-set compensator assy.
*4-11
Cover *4-11
Cover *4-11
Cover
non-set non-set non-set
Item 4 - Compensator Assembly
All left (CCW) or right (CW) directions
given are viewed from the input shaft end of the pump.

9
Model 70122
Item 4 - Compensator Parts List
Item 4 - Parts List (Refer to drawings)
Item Part No. Qty. Description
4(a) 70422-HU 1 Non-Set Pressure-Flow Compensator Assembly, Lefthand Rotation
4(b) 70422-HY 1 Non-Set Pressure-Flow Compensator Assembly, Righthand Rotation
4(c) 70422-HR 1 Non-Set Pressure Compensator Assembly
4-1N/S 1 Compensator Body
4-2N/S 1 Pressure Spool
4-370422-405 1 Spring Pivot Cap
4-417063-11 1 Spring
[phone] O-ring, 2.38 mm Dia. x 14.29 mm I.D. [.0937 in. Dia. x .5625 in. I.D.]
4-670421-453 1 Pressure Spring Follower
[phone] O-ring, 2.38 mm Dia. x 22.23 mm I.D. [.0937 in. Dia. x .875 in. I.D.]
4-870422-606 1 Adjustment Cap, Pressure
4-970422-620 1or2 Set Screw
4-10 16024-4 1or2 Nut
4-11* 70422-618* 1or2 Cover*
4-12 N/S 1 Flow Spool
4-13 70411-411 1 Spring Pivot Cap
4-14 17029-5 1 Spring
[phone] O-ring, 1.59 mm Dia. x 5.55 mm I.D. [.0625 in. Dia. x .2187 in. I.D.]
4-16 70421-477 1 Flow Spring Follower
[phone] O-ring, 1.98 mm Dia. x 11.89 mm I.D. [.078 in. Dia. x .468 in. I.D.]
4-18 70422-602 1 Adjustment Cap Flow
4-19 16103-103 2 Plug Assembly
+ 4-19-1 16133-3 2 O-ring, 1.59 mm Dia. x 7.54 mm I.D. [.0625 in. Dia. x .2969 in. I.D.]
Legend + Included in seal repair kit listed on page 5.
NSS Not Sold Separately
* Covers are not included with Non-Set Compensator
Factory Pre-set Compensator Assemblies listed on page #10.

10
Model 70122
Factory Pre-set Compensator
Assemblies
Pre-set Pressure-Flow Compensator Assemblies
Non-Set Pre-set
Assembly Assembly Pump Rotation Pressure Setting Flow Setting
70422-HU 70422-AY-03 Lefthand (CCW) 210±3.5 bar [3050±50 lbf/in2] 13.8±0.7 bar [200±10 lbf/in2]
70422-HU 70422-BH-03 Lefthand (CCW) 191±2.1 bar [2770±30 lbf/in2] 15.2±0.7 bar [220±10 lbf/in2]
70422-HU 70422-BL-03 Lefthand (CCW) 183±3.5 bar [2650±50 lbf/in2] 25.2±1.8 bar [365±25 lbf/in2]
70422-HU 70422-DE-03 Lefthand (CCW) 193±3.5 bar [2800±50 lbf/in2] 13.8±0.7 bar [200±10 lbf/in2]
70422-HU 70422-DU-03 Lefthand (CCW) 176±3.5 bar [2550±50 lbf/in2] 19.0±1.8 bar [275±25 lbf/in2]
70422-HU 70422-EQ-03 Lefthand (CCW) 210±3.5 bar [3050±50 lbf/in2] 25.9±1.8 bar [375±25 lbf/in2]
70422-HU 70422-GD-03 Lefthand (CCW) 176±3.5 bar [2550±50 lbf/in2] 17.2±1.8 bar [250±25 lbf/in2]
70422-HU 70422-GN-03 Lefthand (CCW) 155±3.5 bar [2250±50 lbf/in2] 19.0±1.8 bar [275±25 lbf/in2]
70422-HU 70422-GP-03 Lefthand (CCW) 169±3.5 bar [2450±50 lbf/in2] 19.0±1.8 bar [275±25 lbf/in2]
70422-HU 70422-HL-03 Lefthand (CCW) 210±3.5 bar [3050±50 lbf/in2] 24.5±1.0 bar [355±15 lbf/in2]
70422-HY 70422-BM-01 Righthand (CW) 210±3.5 bar [3050±50 lbf/in2] 13.8±0.7 bar [200±10 lbf/in2]
70422-HY 70422-BU-01 Righthand (CW) 131±3.5 bar [1900±50 lbf/in2] 13.8±0.7 bar [200±10 lbf/in2]
70422-HY 70422-DB-01 Righthand (CW) 238±3.5 bar [3450±50 lbf/in2] 13.8±0.7 bar [200±10 lbf/in2]
70422-HY 70422-DJ-01 Righthand (CW) 210±3.5 bar [3050±50 lbf/in2] 25.9±1.8 bar [375±25 lbf/in2]
70422-HY 70422-DW-01 Righthand (CW) 155±3.5 bar [2250±50 lbf/in2] 13.8±0.7 bar [200±10 lbf/in2]
70422-HY 70422-ED-01 Righthand (CW) 169±3.5 bar [2450±50 lbf/in2] 19.0±1.8 bar [275±25 lbf/in2]
70422-HY 70422-ET-01 Righthand (CW) 176±3.5 bar [2550±50 lbf/in2] 13.8±0.7 bar [200±10 lbf/in2]
70422-HY 70422-EZ-01 Righthand (CW) 176±3.5 bar [2550±50 lbf/in2] 17.2±0.7 bar [250±10 lbf/in2]
70422-HY 70422-FB-01 Righthand (CW) 191±2.1 bar [2770±30 lbf/in2] 15.2±0.7 bar [220±10 lbf/in2]
70422-HY 70422-FL-01 Righthand (CW) 193±3.5 bar [2800±50 lbf/in2] 20.7±1.0 bar [300±15 lbf/in2]
70422-HY 70422-FR-01 Righthand (CW) 210±3.5 bar [3050±50 lbf/in2] 19.0±1.8 bar [275±25 lbf/in2]
70422-HY 70422-GA-01 Righthand (CW) 172±3.5 bar [2500±50 lbf/in2] 20.7±0.7 bar [300±10 lbf/in2]
70422-HY 70422-GR-01 Righthand (CW) 193±3.5 bar [2800±50 lbf/in2] 17.2±1.8 bar [250±25 lbf/in2]
70422-HY 70422-GU-01 Righthand (CW) 210±3.5 bar [3050±50 lbf/in2] 17.2±1.8 bar [250±25 lbf/in2]
70422-HY 70422-HK-01 Righthand (CW) 210±3.5 bar [3050±50 lbf/in2] 24.5±1.0 bar [355±15 lbf/in2]
70422-HY 70422-HM-01 Righthand (CW) 176±3.5 bar [2550±50 lbf/in2] 24.5±1.0 bar [355±15 lbf/in2]
Pre-set Pressure Compensator Assembly
Non-Set Pre-set
Assembly Assembly Pump Rotation Pressure Setting
70422-HR 70422-CA-04 Both 210±3.5 bar [3050±50 lbf/in2]
70422-HR 70422-CH-04 Both 162±3.5 bar [2350±50 lbf/in2]
70422-HR 70422-CK-04 Both 148±3.5 bar [2150±50 lbf/in2]
70422-HR 70422-CL-04 Both 141±3.5 bar [2050±50 lbf/in2]
70422-HR 70422-CR-04 Both 107±3.5 bar [1550±50 lbf/in2]
70422-HR 70422-DH-04 Both 176±1.8 bar [2550±25 lbf/in2]
70422-HR 70422-FG-04 Both 159±3.5 bar [2300±50 lbf/in2]
70422-HR 70422-GE-04 Both 169±1.8 bar [2450±25 lbf/in2]
70422-HR 70422-HB-04 Both 190±3.5 bar [2750±50 lbf/in2]
70422-HR 70422-HE-04 Both 110±3.5 bar [1600±50 lbf/in2]
70422-HR 70422-HN-04 Both 114±1.8 bar [1650±25 lbf/in2]
All left (CCW) or right (CW) directions
given are viewed from the input shaft end of the pump.

11
Model 70122
5-1
5-2 5-3
5-5
5-4
5-6 5-7 5-8
5-9
5-7
5
Item 5
Rotating Kit Assembly
Item Part No. Qty. Description
570111-695 1 Rotating Kit Assembly
5-1NSS 9 Piston Assembly
5-2NSS 1 Spider
5-3NSS 1 Spider Pivot
5-4NSS 1 Retainer
5-5NSS 1 Piston Block
5-6NSS 3 Pins
5-7NSS 2 Washer
5-8NSS 1 Spring
5-9NSS 1 Retaining Ring
NSS - Not Sold Separately
Item 5 - Rotating Kit Assembly

12
Model 70122
Product Number
This list of product numbers is to aid in Item identification.
If your product number is not listed contact your Eaton representitive.
Model 70122, Lefthand Rotation (CCW)
Description of Part Number
Product Drive Shaft Backplate Assy. Housing Assy. Compensator Assy.
Number Item #1 Item #2 Item #3 Item #4
70122-LAE 70102-201 70120-311 70102-301 70422-CA-04
70122-LAF 70102-201 70120-311 70102-301 70422-AY-03
70122-LAN 70122-203 70120-311 70102-301 70422-CA-04
70122-LAP 70122-203 70120-311 70102-301 70422-AY-03
70122-LAW 70102-200 70120-314 70102-301 70422-AY-03
70122-LAY 70102-200 70120-314 70102-301 70422-CA-04
70122-LAZ 70122-203 70120-314 70102-301 70422-AY-03
70122-LBA 70122-203 70120-314 70120-314 70422-CA-04
Model 70122, Righthand Rotation (CW)
Description of Part Number
Product Drive Shaft Backplate Assy. Housing Assy. Compensator Assy.
Number Item #1 Item #2 Item #3 Item #4
70122-RAG 70102-201 70120-311 70120-314 70422-BM-01
70122-RAH 70102-201 70120-311 70120-314 70422-CA-04
70122-RAL 70122-203 70120-311 70120-314 70422-BM-01
70122-RAM 70122-203 70120-311 70120-314 70422-CA-04
70122-RAV 70102-200 70120-314 70120-314 70422-BM-01
70122-RAW 70102-200 70120-314 70120-314 70422-CA-04
70122-RAY 70122-203 70120-314 70120-314 70422-BM-01
70122-RAZ 70122-203 70120-314 70120-314 70422-CA-04

13
Model 70122
Repair Information
Cleanliness is extremely important when repairing
these pumps. Work in a clean area. Before
disconnecting the lines clean port area of pump.
Disconnect hydraulic lines and remove pump
assembly from vehicle and plug ports. Thoroughly
clean the outside of pump. After cleaning, remove
port plugs and drain oil.
Disassembly
ATTENTION: Removal of the adjusting screw covers
from cap may void the warranty on this assembly.
1 Clamp the end of the drive shaft in a protected
jaw vise with the body of the pump up and remove
the four allen head screws (14) holding compensator
(4).
2 Remove the compensator assembly (4), 0-ring
(28), and gasket (24).
3 Remove the four cap screws (27) from the
backplate of the pump.
4 Place a screw driver in slots provided between
housing and loosen backplate. Remove backplate (2)
and gasket (21) from housing.
5 Remove the control piston (7) remaining on the
backplate or in housing. Also remove plug (2-2) from
backplate (2).
6 To remove rotating assembly (5) from housing,
remove pump from vise and slide rotating assembly
off shaft. Caution: pistons may not come out with
piston block.
7 Remove pistons (5-1), spider (5-2), and spider
pivot (5-3) from piston block (5-5).
8 The piston block assembly (5-5) need not be
disassembled unless the internal pins (5-6) or spring
(5-8) are damaged.
CAUTION: Use the following procedure if the spring
is to be removed from the piston block. The spring
(5-8) is highly compressed and the snap ring (5-9)
should not be removed without compressing the
spring.
The following parts will be needed to disassemble the
piston block:
2 ea. 5/16 l.D. x 15/16 O.D. flat washer,
1 ea. 5/16 x 2-7/8 N.C. cap screw, and
1 ea. 5/16 N.C. nut.
Place one of the flat washers over the 5/16 x 2-7/
8 cap screw and place this through the center of the
piston block. Place the other washer over the cap
screw and let it rest on the three pins. Screw the nut
on and compress the spring inside the piston block.
Use a pair of snap ring pliers and remove the internal
snap ring (5-9). Remove the nut and bolt along with
the two washers (5-7), three pins (5-6), and the
internal pin keeper (5-4).
9 To free shaft seal and shaft, remove retaining
ring (12).
10 Remove shaft (1) from housing (3) by tapping
backplate end of shaft with a wooden or plastic
mallet.
11 Remove shaft seal (17), washer (13), the two
retaining rings (10), the two thrust washers (16), and
bearing (15) from shaft.
12 To remove the camplate (6) from the housing,
remove the two internal retaining rings (11) from the
sides of the housing. Remove the two covers (20),
the two o-rings (26), the two inner races (19), and
the bearings (25). The camplate can now be moved
over to one side and removed. The two camplate
pivot bearings are a loose slip fit into the housing. Do
not be concerned if they are not tight.
13 Remove the spring collar (22) and spring (18).
Do not remove the button (23) and roll pin (9) unless
they are worn or loose.
14 The pressure-flow compensator assembly (4)

14
Model 70122
may be disassembled for cleaning and inspection.
ATTENTION: Removal of the adjusting screw covers
from cap may void the warranty on this assembly.
15 Remove pressure adjustment cap (4-8) from
compensator housing (4-1). Pressure spring follower
(4-6) will remain in cap (4-8), pull follower from cap.
16 Remove flow adjustment cap (4-18) from
compensator housing (4-1). Flow spring follower (4-
16) will remain in cap (4-18). Pull follower from cap.
17 Remove springs (4-4 and 4-14) and spring pivots
(4-3 and 4-13) from compensator housing.
18 Remove plugs (4-19), pressure compensator
spool (4-2), and flow compensator spool (4-12) from
compensator housing (4-1).
19 The shaft seal, all 0-rings, and all gaskets should
be removed and replaced with new items upon
reassembly.
Inspect Parts For Wear
1 Inspect the flat surface of the backplate (2), the
finish on the piston block side should be smooth and
free of grooves. The piston guide should be tight in
the backplate. The needle bearing in the backplate
should be free of excessive play and remain in the
bearing cage. If the backplate has any of the wear
characteristics outlined above, replace complete
backplate assembly.
2 Inspect the piston block (5). The surface that
contacts the backplate should be smooth and free of
grooves.
3 The pistons (5-1) should move freely in the
piston block bore. If they stick in the bore, examine
the bore for scoring or contamination.
4 Examine the O.D. of the piston (5-1) for finish
condition. They should not show wear or deep
scratches. The shoes should be a snug fit on the ball
end of the piston. The flat surface of the shoes
should be flat, and smooth. Do not lap piston shoes.
5 Examine the spider (5-2). It should be flat, no
cracks, and no signs of wear in the pivot area.
6 Examine the pivot (5-3). It should be smooth and
show no signs of wear.
7 Inspect the camplate (6) for the condition of
finish of the polished shoe surface. It should show
no signs of scoring.
8 Inspect shaft (1) for wear in bearing and spline
areas.
9 Inspect thrust bearing (15) and thrust washers
(16) for wear.
10 Inspect the needle bearing in the housing
assembly (3). If the needles are free of excessive play
and remain in the bearing cage, there is no need to
replace the housing.
11 Inspect the compensator springs (4-4 and 4-14)
for breakage or weakness.
12 Inspect the spools (4-2 and 4-12) for scoring.
13 It is not necessary to inspect the o-rings,
retaining rings, gaskets, or shaft seal as they should
be replaced as new items and are included in the seal
repair kit available for this assembly.
Reassembly
1 Clean all parts in suitable solvent; lubricate all
critical moving parts before reassembly.
2 Install camplate control spring (18) and spring
collar (22) in housing (3).
3 Insert camplate (6) into housing (3). Insert
needle bearings (25) and bearing inner race (19) over
the camplate arms and slide into housing (3). The
numbered end of the bearing should face outward
Repair Information

15
Model 70122
and the chamfered l.D. of the race should face
inward.
4 Install new 0-ring (26) around O.D. of camplate
pivot bearing (25). Install trunnion covers (20) and
secure with retaining rings (11).
5 Install retaining ring (10) on shaft (1). Install
thrust washer (16), thrust bearing (15), and second
thrust washer (16). Secure with second retaining ring
(10).
6 Install shaft (1) in housing (3) and install washer
(13), shaft seal (17), and retain with retaining ring
(12). Make sure retaining ring is seated in the
groove.
7 If piston block assembly was disassembled,
compress the pin keeper (5-4), and install in the
spline area of piston block. Install the three pins (5-
6) with the head end to the inside of the block and
install in the special grooves of the piston block
spline.
8 Install the washer (5-7), spring (5-8), and second
washer (5-7) in the piston block. Use the two 5/16
l.D. washers and the 5/16 x 2-7/8 cap screw to
compress the spring and retain with retaining ring
(5-9). Remove the 5/16 x 2-7/8 cap screw and the
two washer.
9 Install the pivot (5-3), spider (5-2), and piston
assemblies (5-1) in the piston block. Install this
assembly in the housing assembly, the piston shoes
must be in contact with the camplate. Be sure all the
parts are in their proper position.
10 Clamp this assembly in a protected jaw vise with
the open end of the housing (3) up.
11 Install new gasket (21).
12 Install control piston (7), and plug (2-2) with new
o-ring onto backplate. Note roll pin (3-2) locations.
13 Install backplate (2) and retain with cap screws
(27). Torque to 23 to 27 N-m [17 to 20 lb-ft].
14 Place new o-ring (4-19-1) on plug (4-19). Install
plug assembly, flow compensator spool (4-12),
spring pivot (4-13), spring (4-14), flow spring
follower (4-16) with new o-ring (4-15), and flow
adjustment cap (4-18) with new o-ring (4-17) into
compensator housing (4-1). Torque plug (4-19) 8 to
11 N-m [6 to 8 lb-ft] and torque flow adjustment cap
(4-18) 14 to 16 N-m [10 to 12 lb-ft ].
15 Place new 0-ring (4-19-1) on plug (4-19). Install
plug assembly, pressure compensator spool (4-2),
spring pivot (4-3), spring (4-4), pressure spring
follower (4-6) with new o-ring (4-5), and pressure
adjustment cap (4-8) with new o-ring (4-7) into
compensator housing (4-1). Torque plug (4-19) 8 to
10 N-m [6 to 8 lb-ft] and torque pressure adjustment
cap (4-18) 47 to 54 N-m [35 to 40 lb-ft].
16 Install new gasket (24) and new o-ring (28), then
install compensator assembly (4),and retain with
four allen head cap screws (14) and torque to 14 to
16 N-m [10 to 12 lb-ft].
17 Plug ports to preserve cleanliness until
installation on vehicle. (Refer to start up procedures.)
Repair Information

16
Model 70122
When initially starting a rebuilt load sensing system,
it is extremely important that the start-up procedure
be followed. It prevents the chance of damaging the
pump which might occur if the system was not
properly purged with oil before start-up.
1 After the pump has been properly installed onto
the machine and all hydraulic connections have been
made, check all fittings to make sure that they are
tight.
2 Fill the pump housing at least 1/2 full with
system oil that has been filtered through a 10 micron
filter.
3 Fill the reservoir with an approved oil that has
been filtered through a 10 micron filter. Leave the
filler cap loose as a means of air that is trapped in the
system.
4 Note on gasoline or L.P. engines: remove the coil
wire and turn the engine over for 15 seconds. Diesel
engines: shut off the fuel flow to the injectors and
turn the engine over for 15 seconds. This procedure
enables the pump to pick-up the oil before start-up.
At this time disconnect the sensor line from the
pump compensator and pull one of the valve spools
while the engine is being turned over. This allows oil
to flow through the sensor line, thus, removing any
air in the sensor line. Reconnect the sensor line after
a steady flow of oil is coming from the line.
5 Replace the coil wire or return the fuel flow to the
injectors and start the engine. Run at low idle speed
for one minute. The pump should immediately pick
up oil and go into low pressure standby. If there is no
indication of fill in 30 seconds, stop engine and
determine the cause.
6 After the pump has stabilized in low pressure
standby, operate the control valve and steering, if the
system is equipped with one, to purge the system of
air and to fill the cylinders with oil. Continue
operating the system slowly with no load until it
responds fully.
7 Check fluid level at the reservoir and refill if
necessary to the proper level at the reservoir and
refill if necessary to the proper level with an
approved filtered oil.
8 Check all line connections for leaks tighten if
necessary.
9 The machine is now ready to be put into
operation.
10 Short hour filter changes are recommended for
the first two changes after placing the machine back
into operation. The first filter would be changed in 3-
5 hours and the second at approximately 50 hours.
Routine scheduled filter changes are recommended
for maximum life of hydraulic system.
Start-up Procedure

17
Model 70122
Fault - Logic
Troubleshooting
This fault - logic troubleshooting guide is a
diagnostic aid in locating pump problems.
Match the pump systems with the problem
statements and follow the action steps shown in the
box diagrams. This will give expedient aid in
correcting minor problems eliminating unnecessary
machine down time.
Following the fault - logic diagrams are diagram
action comments of the action steps shown in the
diagrams. Where applicable, the comment number of
the statement appears in the action block of the
diagrams.
Recommended Gauge Locations
Test Port
Inlet Vacuum - LH. Rotation
System Pressure - RH. Rotation
Load Sensing Port
Tee in Line to Check
Load Sensing Pressure
Test Port
System Pressure - LH. Rotation
Inlet Vacuum - RH. Rotation
Drain Port
Tee in Line to Check
Case Pressure
Gauges Recommended
Inlet vacuum gauge: 2 bar to 1 bar [30 PSI to 30 inHg]
System pressure gauge: 700 bar [10,000 PSI]
Case pressure gauge: 0 to 25 bar [0 to 300 PSI]
1
Inspect
?
Repair
or
Replace
Defective
Action
Step
Comment
Number
Decision
Solution
Symptom:
Explanatory
Diagram

18
Model 70122
Fault - Logic
Troubleshooting
Check
Hyd. Fluid
Specs
OK
OK OK
123
Check
Oil Level in
Reservoir
Improper
Install
Proper
Fluid
Replace
Pump
Inspect
Inlet Screen
or Strainer
Clogged
Clean
or
Replace
Below Level
Fill to
Proper
Level
4
Inspect
Compensator
Signal
Low
Inspect
Signal
Line
Defective
Repair
or
Replace
5
Inspect
Pump
Compensator
Defective
Repair
or
Replace
OK
OK
Symptom:
System will not Develop Proper Pressure or Flow

19
Model 70122
Fault - Logic
Troubleshooting
Check
Hyd. Fluid
Specs OKOK OK
123
Check
Oil Level in
Reservoir
Improper
Install
Proper
Fluid
Replace
Pump
Inspect
Inlet Screen
or Strainer
Clogged
Clean
or
Replace
Below Level
Fill to
Proper
Level
Symptom: Pump Noisy or Overheating
Diagram Action Step Comments
1. Check Oil Level in Reservoir:
A. Fill to proper level.
2. Check Hydraulic Fluid Specifications:
A. Consult owner/operators manual for the
proper type fluid.
3. Inspect Inlet Screen or Strainer for:
A. Suction screen or strainer plugged.
B. Suction line to small or too long
C. Suction line collapsed or plugged.
4. Inspect Compensator Signal for:
A. Improper size or length of signal line.
B. Damaged or obstructed signal line
5. *Inspect Pump Compensator for:
A. Misadjusted pressure or flow setting.
B. Pressure or flow spool stuck open.
C. Pressure or flow spring weak or broken.
*Standard factory compensator pressure settings
A. Pressure compensator set at 3000 to 3100 PSI
(Optional settings of 1500 min. to 3100 max.
PSI)
B. Flow compensator set at 190 to 210 PSI
(Optional settings of 190 min. to 450 max. PSI)

20
Model 70122
Each order must include the following information.
1. Product and/or Part Number
2. Serial Number Code
3. Part Name
4. Quantity