Eaton 26 Series Owner's manual

No. 7-624
October,1995
Eaton®
Gear Pumps
Repair Information
Series 26
Model 26000 Single Gear Pumps

2
Series 26 - Model 26000 Single Gear Pumps
Introduction
Table of Contents
Introduction ................................................................................................................................ 2
Identification............................................................................................................................... 3
Tools Required ........................................................................................................................... 3
Exploded View Drawing .............................................................................................................. 4
Parts List .................................................................................................................................... 5
Disassembly ............................................................................................................................... 5 & 6
Reversibility ................................................................................................................................ 7
Inspection................................................................................................................................... 8
Reassembly ................................................................................................................................9 & 10
Specific Backplate Parts List.......................................................................................................11 &12
Placing Pump Back into Operation ............................................................................................. 13
Trouble Shooting ........................................................................................................................ 14
Ordering Information .................................................................................................................. 16
Introduction
This manual provides service information for the Eaton model 26000 single gear pumps. Step by step
instructions for the complete disassembly, inspection, and reassembly of the pumps are included.
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.
For replacement parts and ordering information refer to parts list 6-634.
Lubricate the new rubber seals with a petroleum jelly (vaseline) before installation.
Torque all bolts over gasket joints, then repeat the torquing sequence to makeup for gasket
compression.
Verifying the accuracy of pump repairs on an authorized test stand is essential.

3
Series 26 - Model 26000 Single Gear Pumps
Identification and Tools
Required
B 95 01 31 JB Serial Number Code:
Series
26 = Gear Pump
( SAE "A" Mount )
Features
0 = Standard Single Pump
1= Standard Single W/ Relief
2= Flow Divider Backplate
3= Flow Divider W/ Load Sense
4= Tandem Backplate
5= Multiple Pumps
Displacement cm3/r [ in3/r]
01 = 6.6 [.40] 08 = 22.5 [1.37]
02 = 8.2 [.50] 09 = 24.3 [1.48]
03 = 9.5 [.58] 10 = 25.2 [1.54]
04 = 10.8 [.66] 11 = 27.7 [1.69]
05 = 13.8 [.84] 12 = 29.0 [1.77]
06 = 16.7 [1.02] 13 = 30.6 [1.87]
07 = 19.7 [1.20]
Input Rotation
R= Right-hand (clockwise)
L= Left-hand (Counterclockwise)
Catalog / Non-Catalog
Z= Cataloged Pump
A-Y = Non-Cataloged Pump
Shafts , Porting Size and Location
Side Ports
A= 3/4 in. 11 Tooth, 1 5/16-12 UN-2B Suction, 7/8-14 UNF-2B Pressure
C= 3/4 in. Str. Keyed, 1 5/16-12 UN-2B Suction, 7/8-14 UNF-2B Pressure
E= 3/4 in. 9 Tooth, 1 5/16-12 UN-2B Suction, 7/8-14 UNF-2B Pressure
G= 5/8 in. Str. Keyed, 1 1/16-12 UN-2B Suction, 7/8-14 UNF-2B Pressure
J= 5/8 in. 9 Tooth, 1 1/16-12 UN-2B Suction, 7/8-14 UNF-2B Pressure
L= 5/8 in. Str. Keyed, 1 5/16-12 UN-2B Suction, 7/8-14 UNF-2B Pressure
N= 3/4 in. 11 Tooth, 1 1/16-12 UN-2B Suction, 7/8-14 UNF-2B Pressure
R= 3/4 in. Str. Keyed, 1 1/16-12 UN-2B Suction, 7/8-14 UNF-2B Pressure
Rear Ports
B= 3/4 in. 11 Tooth, 1 5/16-12 UN-2B Suction, 7/8-14 UNF-2B Pressure
D= 3/4 in. Str. Keyed, 1 5/16-12 UN-2B Suction, 7/8-14 UNF-2B Pressure
F= 3/4 in. 9 Tooth, 1 5/16-12 UN-2B Suction, 7/8-14 UNF-2B Pressure
H= 5/8 in. Str. Keyed, 1 1/16-12 UN-2B Suction, 7/8-14 UNF-2B Pressure
K= 5/8 in. 9 Tooth, 1 1/16-12 UN-2B Suction, 7/8-14 UNF-2B Pressure
M= 5/8 in. Str. Keyed, 1 5/16-12 UN-2B Suction, 7/8-14 UNF-2B Pressure
P= 3/4 in. 11 Tooth, 1 1/16-12 UN-2B Suction, 7/8-14 UNF-2B Pressure
S= 3/4 in. Str. Keyed, 1 1/16-12 UN-2B Suction, 7/8-14 UNF-2B Pressure
Product Number: 26 0 01 - R Z A
Tools Required
3/8 in. socket and ratchet wrench
Internal Retaining Ring Pliers
(straight .090 tip)
O-ring Pick
Thread 3/8 dia. UNC bolt/screw
Torque Wrench
(135.6 N.m [100 lbf.ft] capacity)
Hammer (soft face)
Light Petroleum Jelly
Seal Driver
Arbor Press
Testers Initials
Day of Month (two digits)
Month (two digits)
Last two digits of year built.
( 95 for 1995 etc.)
Revision level of parts list.

4
Series 26 - Model 26000 Single Gear Pumps
Parts
Drawing
Righthand (CW)
Rotation Pump
Lefthand (CCW)
Rotation Pump
3
Body
1
Front Plate
11
Cap Screws
17
Washer
8
O- ring
8
O-ring
40
Plug
12
Backup Gasket
13
Seal
7
Wear Plate
4C
Drive Gear
Assembly
5
Idler Gear
Assembly
10
Washer
L
R
9
Shaft seal
25
Optional
Retaining
Ring
4A
Drive Gear
Assembly
4D
Drive Gear
Assembly
4B
Drive Gear
Assembly
14a
Key
14b
Key
2
Backplate
3
Body
1
Front Plate
11
Cap Screws
17
Washer
8
O- ring
8
O-ring
40
Plug
12
Backup Gasket
13
Seal
7
Wear Plate
4C
Drive Gear
Assembly
5
Idler Gear
Assembly
10
Washer
L
R
9
Shaft seal
25
Optional
Retaining
Ring
14a
Key
2
Backplate

5
Series 26 - Model 26000 Single Gear Pumps
Disassembly Parts List
Item
No. Description Qty.
1 Front plate Assembly 1
2 Backplate 1
3 Body Assembly 1
4 Drive Gear Assembly 1
5 Idler Gear Assembly 1
~ 7 Wear Plate 1
~ 8 O-ring 2
~ 9 Shaft Seal 1
~ 10 Washer 1
11 Cap Screw 8
~ 12 Backup Gasket 1
~ 13 Seal 1
14 Key for Straight Shaft 1
~ 17 Washer 4
25 Retaining Ring (optional) 1
40 Plug 1
~ Seal Kit 26000-901 for Single Pumps
6 Remove o-ring seal from backplate.
7 To disassemble the relief valve backplate, flow divider
backplate, and tandem flow divider backplate see page 11 &
12.
Repair Information - Model 26000
Work in a clean area; cleanliness is extremely important when
repairing hydraulic pumps. Before disconnecting the lines,
clean port area of pump. Disconnect hydraulic lines, removing
pump assembly from vehicle and plugging ports. Thoroughly
clean the outside of pump. After cleaning, remove port plugs
and drain oil.
Disassembly
1 Remove key from drive shaft if keyed drive gear assembly
is used.
2 Put a location mark across front plate, body and backplate
to assure proper reassembly.
3 Clamp pump in vise, shaft end up.
4 Remove cap screws (eight each) and washer (four each).
5 Remove pump from vise, hold pump in hands and tap
shaft with plastic hammer or rawhide mallet to separate front
plate from backplate. Body will remain with either front plate or
backplate.

6
Series 26 - Model 26000 Single Gear Pumps
Disassembly
8 Remove idler gear assembly from body.
9 To separate body from the plate it remained with, place
drive gear assembly in gear pocket and tap protruding end with
plastic hammer or rawhide mallet. Remove drive gear
assembly.
10 Remove wear plate and o-ring seal, noting position of
open side of wear plate.
11 Remove back-up gasket and seal from wear plate by
extracting with a o-ring tool.
12 Remove snap ring (if applicable) from the front of the front
plate shaft seal area.
13 Remove shaft seal and washer from front plate with a
blunt punch from the back side.
14 Removing the plug in front plate is not necessary, unless
you intend to change rotation. See Reversibility - Changing
Input Rotation of Pump.

7
Series 26 - Model 26000 Single Gear Pumps
Reversibility
Changing Input Rotation of Pump
1 Place pump in a protected jaw vise with shaft end up.
Remove the eight cap screws.
2 Remove front plate, noting orientation of drive shaft
through bearing in reference to the backplate.
3 Notice the location of the open side of wear plate and
remove wear plate.
4 Switch drive gear and idler gear within gear pockets. Do
not flip idler gear end for end.
Note: Gear housing body and backplate do not need altering.
5 Re-install wear plate into gear pockets over the gears with
seal and backup gasket up. (Same orientation as removed)
6 Front plate disassembly and assembly:
- Thread 3/8 UNC threaded bolt into plug cavity. Start
with fingers, then place bolt head in vise and turn front
plate to engage threads 2-3 turns.
- Holding bolt in vise, tap front plate with rubber
hammer to disengage plug .
- Remove plug from bolt.
- Install plug in the other casting cavity and tap flush
with rubber hammer. Note L or R at bottom of cavity.
40
Plug
40
Plug
Open for
righthand
rotation
Open for
lefthand
rotation
R
L
R
L
- Ensure that bearing drain holes are free of debris.
- Note proper placement of o-ring in groove of front
plate.
7 Hold o-ring in groove of front plate with petroleum jelly.
Reassemble front plate over drive shaft end, being careful not
to damage shaft seal.
8 Torque 8 cap screws 34 to 38 N•m [25 to 28 lbf•ft].
9 Lubricate gears and mating surfaces with hydraulic oil
through ports.
10 Rotate shaft (manually) to ensure proper assembly of
components.

8
Series 26 - Model 26000 Single Gear Pumps
Inspection
Model Number 26001 26002 26003 26004 26005 26006 26007 26008 26009 26010 26011 26012 26013
Pump Disp. 6,6 8,2 9,5 10,8 13,8 16,7 19,7 22,5 24,3 25,2 27,7 29,0 30,6
cm3/r [in3/r] [.40] [.50] [.58] [.66] [.84] [1.02] [1.20] [1.37] [1.48] [1.54] [1.69] [1.77] [1.87]
Gear Width 7,85 9,75 11,20 12,95 16,15 19,35 22,56 25,76 28,12 28,96 32,16 33,78 35,36
mm [in] [.309] [.384] [.441] [.510] [.636] [.762] [.888] [1.014] [1.107] [1.140] [1.266] [1.330] [1.392]
Front plate and Backplate Inspection
1Oil groove in bushings in front plate should be in line with
dowel pin holes and 180°apart. The oil grooves in the
backplate bushings should be at approximately 37°to the
pressure side.
2Replace the backplate or front plate if I.D. of bushings
exceed 19,2 mm [.755 in] (Bushings are not available as
separate items).
3Bushings in front plate should be at 3,20 mm [.126 in]
above surface of front plate.
4Check for scoring on face of backplate. Replace if wear
exceeds ,038 mm [.0015 in.].
Body Inspection
1Check body inside gear pockets for excessive scoring or
wear.
2 Replace body if I.D. of gear pockets exceeds 43,7 mm
[1.719 in].
Inspect Parts for Wear
General
1 Clean and dry all parts.
2 Remove all nicks and burrs from all parts with emery
cloth.
Gear Assembly Inspection
1 Check spline drive shaft for twisted or broken teeth or
check keyed drive shaft for broken or chipped keyway.
2Inspect both the drive gear and idler gear shafts at
bushing points and seal area for rough surfaces and excessive
wear.
3Replace gear assembly if shaft measures less than 19 mm
[ .748 in] in bushing area. (One gear assembly may be replaced
separately; shafts and gears are available as assemblies only.)
4Inspect gear for scoring and excessive wear.
5Replace gear assembly if gear width is below the following
dimensions. Refer to chart on this page.
6Assure that snap rings are in grooves on either side of
drive and idler gears.
7If edge of gear teeth are sharp, break edge with emery
cloth.

9
Series 26 - Model 26000 Single Gear Pumps
4 Install new seal and new backup gasket into wear plate.
Note in the middle of the backup gasket a flat section or
support. This area must face away from the wear plate inside
the seal.
5 Place new wear plate, seal, and backup gasket into gear
pocket with seal and backup gasket next to front plate. The side
of the wear plate with the mid section cut-away must be on the
suction side of pump.
6 Dip gear assemblies into oil and slip into front plate
bushings and gears into pockets of body.
Reassembly
General Information
It is important that the relationship of the backplate, body, wear
plate and front plate is correct. You will note two half moon
cavities in the body. Note: The smaller half moon port cavity
must be on the pressure side of the pump. The side of wear
plate with midsection cut out must be on suction side of pump.
Suction side of backplate is always side with larger port boss.
Reassembly
1 During the reassembly replace the wear plate, seal, back-up
gasket, shaft seal and o-rings as new parts.
2 Install o-ring in groove of front plate.
3 Apply a thin coat of petroleum jelly or hydraulic oil to both
milled gear pockets of body. Slip body onto front plate with half
moon port cavities in body facing away from front plate.
Note: The small half moon port cavity must be on the pressure
side (the plugged side of the front plate) of pump.

10
Series 26 - Model 26000 Single Gear Pumps
Reassembly
7 Install new o-ring in groove of backplate.
8 Make sure port orientation is correct and then slide
backplate over gear shafts until dowel pins are engaged.
9 Secure with cap screws and new washers . Tighten cap
screws evenly in a crisscross pattern 34 to 38 N•m [25 to 28
lbf•ft] torque.
10 Place washer over drive shaft into housing. Liberally oil
shaft seal and install over drive shaft, carefully so that rubber
sealing lips are not cut.
11 Place 1-5/16 in. O.D. sleeve over shaft and press in shaft
seal until flush with front surface of front plate.
13 Install key on keyed shaft.
Note: Refer to Start-up Procedure and Trouble Shooting
Procedure.

11
Series 26 - Model 26000 Single Gear Pumps
Specific Backplate Parts List
Item
No. Description Qty.
2 Relief Valve Backplate 1
18 O-ring 3
19A Relief Valve Assembly 1
19A1 Relief Valve 1
~ 19A2 O-ring 1
~ 19A3 Backup Ring 1
~ 19A4 O-ring 1
19B Plug Assembly 1
19B1 Plug 1
Item
No. Description Qty.
2C Flow Divider Backplate 1
19A Relief Valve Assembly 1
19A1 Relief Valve 1
~ 19A2 O-ring 1
~ 19A3 Backup Ring 1
~ 19A4 O-ring 1
19B Plug Assembly 1
19B1 Plug 1
20 Flow Divider Spool 1
21 Plug/O-ring Assembly 1
21A Plug 1
~ 21B O-ring 2
22 Plug/O-ring Assembly 1
22A Plug 1
23 Spring 1
24 Shim (.0239 inch thick) A/R
A/R – As Required
3 Remove flow divider plugs, shims, spring, and spool from
backplate. (Notice orientation of spool with cavity in backplate)
4 Install new plug seals on plugs. Install spool, spring,
shims, and plug assemblies into backplate. Torque plugs 29 to
33 N•m [21 to 24 lbf•ft]
21B
22A
22
2C
20
23
24
19A4
21A
21
19A319A2
19B1
19B
21B
19A4
19A2
19A3
19A1
19A
Flow Divider Backplate
Disasembly and Reassembly
1 After removing relief valve or plug , remove and replace o-
ring and backup ring with new parts.
2 Install relief valve or plug and torque 41 to 46 N•m [30 to
34 lbf•ft]
19A4
19A2
19A3
19A1
19A
2B
Relief Valve Backplate
Disasembly and Reassembly
1 After removing relief valve , remove and replace o-rings
and backup ring with new parts.
2 Install relief valve and torque 41 to 46 N•m [30 to 34 lbf•ft]

12
Series 26 - Model 26000 Single Gear Pumps
Specific Backplate Parts List
29A
29B
35
30
34
2D
29
27 26
33
32
18
20A
23A
24
28B28A
28
Tandem Flow Divider Backplate
Item
No. Description Qty.
2D Tandem Flow Divider Backplate 1
2E Tandem Backplate 1
18 O-ring 3
20A Spool for Tandem Flow Divider Backplate
23A Spring for Tandem Flow Divider Backplate 1
24 Shim (.0239 inch thick) A/R
~ 26 O-ring 1
27 Plug 1
28 Plug/O-ring Assembly 1
28A Plug 1
~ 28B O-ring 2
29 Plug/O-ring Assembly 1
29A Plug 1
~ 29B O-ring 1
30 Relief Valve Spring 1
32 Sleeve 1
33 Spring 1
34 Poppet 1
35 Shim Washer (.010 inch thick) A/R
36 Tandem Cover Plate 1
37 O-ring 1
38 Cap Screw 2
A/R – As Required
Tandem Backplate
2E
37
36
38
Disasembly and Reassembly
1 Remove relief valve plug, shim, spring, and poppet from
backplate. Do not remove internal relief valve seat. Seat is
loctited to a predetermined depth. Remove o-ring from plug
and replace with new o-ring.
2 Install poppet, spring, shim, and relief valve plug and
torque 14 to 16 N•m [10 to 12 lbf•ft]
3 Remove flow divider plugs, shims, springs, spool, and
sleeve from backplate. (Notice orientation of spool with cavity
in backplate) Remove o-rings from sleeve and replace with new
o-rings .
4 Install sleeve, spool, springs, shims, and plug assemblies
into backplate. Torque plug #27 48 to 54 N•m [35 to 40 lbf•ft]
and plug #28 29 to 33 N•m [21 to 24 lbf•ft]

13
Series 26 - Model 26000 Single Gear Pumps
Placing Series 26 Gear Pump
Back into Operation
Connect
to
Fluid Supply
Mount Pump
on
Machine
Check
for
Leaks
Pump
Ready for
Service
Start Pump
and
Run For
3 Minutes
Each
At 1/2 Speed At 1/2 Speed At Full Speed
At
Zero
Pressure
Load
Intermittently
to 1000 lbf/in
2
Load
Intermittently
to 500 lbf/in
2
When test stand is not available .
When test stand is
available .
Connect
to
Fluid Supply
Mount Pump
on
Test Stand
Check
for
Leaks
Pump
Ready for
Service
Start Pump
and
Run For
3 Minutes
Each
At
Zero
Pressure
Load
Intermittently
to 1000 lbf/in
2
Load
Intermittently
to 500 lbf/in
2
Remove
from
Test Stand
Load
Intermittently
to 2000 lbf/in
2

14
Series 26 - Model 26000 Single Gear Pumps
Trouble Shooting
Problem Possible Cause Correction
Cavitation a. Oil too heavy. a. Change to proper viscosity
b. Oil filter plugged. b. Clean filter.
c. Suction line plugged or too small. c. Clean line and check size of line.
Oil heating a. Oil supply low. a. Fill reservoir.
b. Contaminated oil. b. Drain reservoir and refill with clean oil.
c. Setting of relief valve too high or
too low. c. Set to correct pressure.
d. Oil in system too light. d. Drain reservoir and refill with proper
viscosity oil.
Shaft seal leakage a. Worn shaft seal. a. Replace shaft seal.
b. Worn shaft in seal area. b. Replace drive assembly.
c. Debris in shaft seal suction side
drain holes. c. Disassemble pump and inspect.
Foaming oil a. Low oil level a. Fill reservoir.
b. Air leaking into suction line b. Tighten fittings.
c. Wrong kind of oil. c. Drain and fill reservoir with
non-foaming oil.

15
Series 26 - Model 26000 Single Gear Pumps
Note
Wear Plate Identification
A product improvement has been made to the Model 26000 gear pump with a new designed wear plate. To identify the new wear
plate, look for grooves placed in the seal side of the wear plate as shown below.
This new wear plate enables better pressure clamping with aerated oil in pumps 1.37 cubic inch or smaller. Aerated oil
may occur during a cold start-up in applications with long suction lines or when the mouth of the inlet line is temporarily
exposed to air.
New Groove
New Groove
New Groove
OLD
Wear Plate
NEW
Wear Plate

Eaton Corporation
Hydraulics Division
15151 Hwy. 5
Eden Prairie, MN 55344
Telephone [phone]
Fax [phone]
Eaton Ltd.
Hydraulics Division
Glenrothes, Fife
Scotland, KY7 4NW
Telephone [phone]
Fax [phone]
Eaton GmbH
Hydraulics Products
Am Schimmersfeld 7
40880 Ratingen, Germany
Telephone [phone]
Fax [phone]
ISO-9001 CERTIFICATED FIRM
DET NORSKE VERITAS INDUSTRY BV, THE NETHERLANDS
ACCREDITED BY
THE DUTCH COUNCIL
FOR CERTIFICATION
Reg. No. 24
Quality System Certified
Products in this catalog are manufactured
in an ISO-9001-certified site.
Form No. 7-624 Copyright Eaton Corporation, 1995
All Rights Reserved
Printed in USA
Order parts from 6-634 Parts Information booklet.
Each order must include the following information.
1. Product and/or Part Number
2. Serial Number Code
3. Part Name
4. Quantity