Load-sensing control block

in sandwich plate design

SB24/34
Control block assembly – Control blocks with central connecting plate

Assembly Instructions
RE 66170-11-R/2019-05-07 English
© Bosch Rexroth AG 2019. All rights reserved,
also regarding any disposal, exploitation,
reproduction, editing, distribution, as well
as in the event of applications for industrial
property rights. The data specified within only
serves to describe the product. No statements
concerning a certain condition or suitability
for a certain application can be derived from
our information. The information given does
not release the user from the obligation of
own judgment and verification. It must be
remembered that our products are subject to
a natural process of wear and aging.

The cover shows an example application.

The product delivered may differ from the
image on the cover.

The original repair manual was created in the

German language.
 Contents
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Contents
1 About this documentation 4
1.1 Validity of the documentation 4
1.2 Required and supplementary documentation 4
1.3 Representation of information 5
1.3.1 Symbols 5
1.3.2 Designations 5
1.3.3 Abbreviations 6
2 Safety instructions 7
3 General instructions on property damage and product damage 7
4 About these products 8
4.1 Overview of control block segments 8
4.2 Tie rod bores and threads 8
4.3 Tie rod 9
4.4 Nut 9
4.5 EHS pilot oil bores 10
4.6 Configuring the control block 11
4.7 Alignment of the control block on the working surface 11
5 Assembly description 12
5.1 Control block assembly 12
5.1.1 Preparation of the block segments for the assembly 12
5.1.2 Assembly, central connecting plate , side 13
5.1.3 Assembly, directional valve section 13
5.1.4 Assembly, directional valve section 14
5.1.5 Assembly, end plate / end valve 14
5.1.6 Assembly, central connecting plate , side 15
5.1.7 Assembly, directional valve section 16
5.1.8 Assembly, directional valve section , 16
5.1.9 Assembly, connecting plate / connection valve 17
5.2 Control block disassembly 18
5.2.1 Preparation of the disassembly 18
5.2.2 Disassembly, end plate / end valve , side 18
5.2.3 Disassembly, directional valve section , 18
5.2.4 Disassembly, connecting plate 19
5.2.5 Disassembly, connecting plate / connection valve , side 19
5.2.6 Disassembly, directional valve section , , 19
5.2.7 Disassembly, central connecting plate 20
6 Repairing the flange surface 21
6.1 Sealing elements for control block segments 21
6.2 Repairing the shuttle valve 22
6.3 Repairing the spring pre-tensioned shuttle valve 23

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4/28 About this documentation

1 About this documentation

1.1 Validity of the documentation

This documentation applies to load-sensing control blocks SB24/34 of
Bosch Rexroth including the following control block segments:
••Connecting plate, central connecting plate, intermediate plate and end plate
••Control valves SB24-M, SB24-EHS and SB34-EHS
••Hitch control valves EHR24-EHS and EHR24-EM2

▶▶ Read this documentation completely and, in particular, the chapter 2 "Safety

instructions" and the chapter 3 "General instructions on property and product
damage" in the related instruction manual 66170-B before you start working with
the product.

1.2 Required and supplementary documentation

▶▶ Only commission the product if the documentation marked with the
book symbol  is available to you and you have understood and observed it.

Table 1: Required and supplementary documentation

Title Document number Document type
Load-sensing control block SB24/34 66170-B Instruction manual
Contains important information on the safe and proper transport, installation,
commissioning, maintenance and disassembly of the SB24/34 control block.
Technical data sheet Data sheet
Contains the permissible technical data.
Please bear in mind that different technical data sheets apply depending
on the version:
Load-sensing control block SB24/34 66170
Load-sensing directional valves in sandwich plate design SB24-EHS, SB34-EHS 66171
Load-sensing directional valves in sandwich plate design SB24-M 66172
Plates SB24, SB34 66173
Hitch control valves EHR5, EHR24-EM2, EHR24-EHS 66126

For related documentation on the assembly and repair, please refer to the
above-mentioned manual and, if necessary, to
www.boschrexroth.com/mobile-hydraulics-catalog.

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 About this documentation 5/28

1.3 Representation of information

Uniform safety instructions, symbols, terms and abbreviations are used throughout
this documentation to ensure safe and proper use of the product. For clarification,
they are explained in the sections below.

1.3.1 Symbols
The following symbols indicate notices that are not safety-relevant but increase
understanding of the documentation.

Table 2: Meaning of symbols

Symbol Meaning
If this information is disregarded, the product cannot be used and/or
operated to its full extent.

▶▶ Single, independent action

1. Numbered instruction:
2. The numbers indicate that the actions must be completed in order.

3.
Black circle with white number:
Auxiliary marking for a better understanding.
White circle with black number: Position or assembly group with
reference to the parts list and to the graphics within a chapter.
White circle with black letters: Assembly group with reference to the
parts list and to the graphics within a chapter.

1.3.2 Designations
This documentation uses the following designations:

Table 3: Designations

Designation Meaning
SB24-M Control valve with mechanical control
SB24-EHS/SB34-EHS Control valve with CAN bus-controlled electrohydraulic actuating unit
EHR24-EHS Control valve with CAN bus-controlled electrohydraulic actuating unit
for electrohydraulic hitch control
EHR24-EM2 Control valve with PWM signal control for electrohydraulic hitch control
Control valve Directional valve type SB
Hitch control valve Directional valve type EHR

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1.3.3 Abbreviations
This documentation uses the following abbreviations:

Table 4: Abbreviations

Abbreviation Meaning
AP Connecting plate
CVL Connection valve (with LS signaling direction from right to left)
EHR Electrohydraulic hitch control
EHS Electrohydraulic actuating unit
EVL End valve (with LS signaling direction from right to left)
EP End plate
SVL Standard valve (with LS signaling direction from right to left)
ZAP Central connecting plate

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2 Safety instructions
▶▶ Always follow all safety instructions in the instruction manual 66170-B.

3 General instructions on property

damage and product damage
▶▶ Always follow all instructions in the instruction manual 66170-B.

Housing and parts ••Rexroth original spare parts may be used only.
••Replace elastic sealing elements after disassembly.
••The housing and parts must be clean and undamaged.
••Damaged housings and parts may not be used again.
••Reworking threads is not permissible.
••Reworking bores is not permissible.
••Protect bores and threads from any deposition of dirt.

Flange surfaces and ••During disassembly, adhesion forces might take an effect between the
sealing surfaces flange surfaces.
••Remove any contamination with a whetstone and clean it with a cleaning cloth.
••Surfaces with imprints or signs of wear in the sealing surface may not be continued
to be used.
••Reworking sealing surfaces is not permissible.

Bench vise ••Use protective jaws with hard rubber. Sealing and flange surfaces may not be
damaged.

Required tools ••Oil-soaked cleaning cloth

••Whetstone
••Mechanical tools
••Torque wrench

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4 About these products

To ensure clear presentation of the control block assembly / disassembly, the

representation of the control block segments has been simplified and/or reduced
to the essential and summarized in dummies.
The work steps are described based on a control block with dummy block
segments.

4.1 Overview of control block segments

Plates

▲▲ End plate (EP) ▲▲ Central connecting plate (ZAP) ▲▲ Connecting plate (AP)

Directional valves

▲▲ End valve (EVL) ▲▲ Standard directional valve ▲▲ Connection valve (CVL) ▲▲ Hitch control valve
(SVL) EHR24-EM2

4.2 Tie rod bores and threads

The control block segments are clamped together by means of tie rods and nuts.
For this purpose, the control block is provided with threaded bores at one control
block segment and the following control block segments are provided with through
bores in the flange surfaces.
At the final control block segment, the tie rods protrude at the end surface.
On the protrusion, the tie rod nuts are located.

Example:
Bore Bore Thread Bore Bore
Nut EP / EVL SVL ZAP SVL AP / CVL Nut

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4.3 Tie rod

▶▶ Use tie rods (stud screws) according to DIN 835 - M10 × length, property class 10.9.

On each shaft end and , the tie rod is provided with a thread for different use.
••Interference thread with 20 mm length (thread undercut + thread), which is
screwed into the ZAP.
••Nut thread

The required tie rod length depends on the number and combination of the
control block segments.
The tie rod length L is determined as follows: L =  +   + 

The determination process for the required tie rod length is exactly described in
data sheet 66170.

NOTICE! The tie rods must not be deformed during assembly/disassembly of the
control block segments!

4.4 Nut
For the tie rod nut thread , different nuts are used, depending on the final
control block segment (AP or CVL and/or EP or EVL).

▲▲ DIN 970–M10 for connecting plate (AP) ▲▲ Shoulder nut M10 for connection valve
and end plate (EP) (CVL) and end valve (EVL)

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4.5 EHS pilot oil bores

For control blocks in EHS version, control block segments with pilot oil line X and Rx
are required.
With mixed control blocks (control block segments with and without EHS), the
pilot oil line X and Rx has to be considered in the control block segment selection.
The position of the control block segment with the pilot oil feed influences the order
and/or version of the following control block segments.

To control block segments without EHS, the following applies:

••With continuous pilot oil line X and Rx, if any of the following control block
segments requires the pilot oil line X and Rx.

▲▲ O-ring side: ▲▲ Opposite O-ring side:

X and Rx with O-ring counterbores and X and Rx with through bore
O-rings

••Without continuous pilot oil line X and Rx, if none of the following control block
segment requires the pilot oil line X and Rx.

▲▲ O-ring side: ▲▲ Opposite O-ring side:

X and Rx with O-ring counterbores and closed
O-rings

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4.6 Configuring the control block

1. Determine the desired order of the block segments (see chapter 4.2),
e.g. starting with the central connecting plate.
2. Determine the tie rod length (see chapter 4.3).
3. Consider the control block segments with pilot oil line X and Rx in the order
(see chapter 4.5).
4. Determine the tie rod nut (see chapter 4.4) depending on the version of the final
control block segment (end plate or end valve).

4.7 Alignment of the control block on the working surface

The control block segments can only be assembled / disassembled horizontally.

In case of horizontal assembly, the height difference of the individual block

segments should be compensated with a suitable underlayer from the fifth control
block segment in order to ensure safe orientation of the control block segments to
each other.

▲▲ Compensating height differences

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5 Assembly description

The assembly / disassembly is described using two dummy control blocks with
7 block segments each as example.

Table 5: Control block segments

Position Designation Abbreviation Control block side

Central connecting plate ZAP

, Directional valve SB / EHR SVL

End valve EVL

End plate EP

, Directional valve SB / EHR SVL

Directional valve EHR-EM2 SVL

Connection valve CVL

Connecting plate AP

▲▲ Example with end plate ▲▲ Example with end valve

5.1 Control block assembly

5.1.1 Preparation of the block segments for the assembly

Prepare the flange surface O-ring side of the block segments as follows:
1. Block segments with shuttle valve:
Assemble the shuttle valve according to chapter 6.2 "Repairing the shuttle valve".
2. Block segments with shuttle valve with spring pre-tension:
Assemble the shuttle valve according to chapter 6.3 "Repairing the spring pre-
tensioned shuttle valve".
3. Assemble the sealing elements according to chapter 6.1 "Sealing elements for
control block segments".

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5.1.2 Assembly, central connecting plate , side

1. Manually screw-in the three tie rod screws ... with the thread side into the
tie rod thread bores ... of the connecting plate in a clockwise direction
and tighten them. Tightening torque MA = 45+5 Nm.

5.1.3 Assembly, directional valve section

▶▶ Orientate the control block segment with the flange surface of the opposite
O-ring side to the connecting plate and slide it via the tie rod screws ... to
the stop at the connecting plate .

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5.1.4 Assembly, directional valve section

▶▶ Orientate the control block segment with the flange surface of the opposite
O-ring side to the already mounted control block segment and slide on via the tie
rod screws ... to the stop.

5.1.5 Assembly, end plate / end valve

1. Orientate the end plate / end valve with the flange surface of the opposite
O-ring side to the already mounted control block segment and slide on via the tie
rod screws ... to the stop.
2. Screw the nuts and/or onto the tie rods ... without using any washers or
locking washers.

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3. Align the control block segments to each other and pre-tension the
nuts and/or in the order with a torque of approx. 5+1 Nm.
4. Tighten the nuts and/or in the order . Tightening torque
MA = 45+5 Nm.

5.1.6 Assembly, central connecting plate , side

For a better overview, only the relevant control block side of the ZAP is shown.

1. Manually screw-in the three tie rod screws ... with the thread side into the
tie rod thread bores ... of the connecting plate in a clockwise direction
and tighten them. Tightening torque MA = 45+5 Nm.

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5.1.7 Assembly, directional valve section

▶▶ Orientate the control block segment with the flange surface of the O-ring
side to the connecting plate and slide it via the tie rod screws ... to the
stop at the connecting plate .

5.1.8 Assembly, directional valve section ,

▶▶ Orientate the control block segments , with the flange surface of the O-ring
side to the already mounted control block segment and slide on via the tie rod
screws ... to the stop.

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5.1.9 Assembly, connecting plate / connection valve

1. Orientate the connecting plate / connection valve with the flange surface
of the O-ring side to the already mounted control block segment and slide on
via the tie rod screws ... to the stop.
2. Screw the nuts and/or onto the tie rods ... without using any washers or
locking washers.

3. Align the control block segments to each other and pre-tension the
nuts and/or in the order with a torque of approx. 5+1 Nm.
4. Tighten the nuts and/or in the order . Tightening torque
MA = 45+5 Nm.

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5.2 Control block disassembly

5.2.1 Preparation of the disassembly

▶▶ Dismount the control block according to the parameters provided by the machine
manufacturer and place it on a clean and stable underlayer.
▶▶ The height difference of the individual block segments is to be equalized with
a suitable underlayer. The sealing and flange surfaces may not be damaged by the
underlayer (see chapter 4.7).
▶▶ The control block segments are to be numbered individually.

5.2.2 Disassembly, end plate / end valve , side

For a better overview, only the relevant control block side of the ZAP is shown.

1. Loosen the nuts and/or by turning them counterclockwise and remove them
from the tie rods … .
2. Remove the end plate / end valve via the tie rods … without jamming.

5.2.3 Disassembly, directional valve section ,

▶▶ Remove the control block segments , one after another via the tie rods … .

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5.2.4 Disassembly, connecting plate

▶▶ Loosen the three tie rods … by turning them counter-clockwise and unscrew
them from the connecting plate .

5.2.5 Disassembly, connecting plate / connection valve , side

1. Loosen the nuts and/or by turning them counterclockwise and remove them
from the tie rods … .
2. Remove the connecting plate / connection valve via the tie rods …
without jamming.

5.2.6 Disassembly, directional valve section , ,

▶▶ Remove the control block segments , , one after another via the
tie rods … .

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5.2.7 Disassembly, central connecting plate

▶▶ Loosen the three tie rods … by turning them counter-clockwise and unscrew
them from the connecting plate .

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6 Repairing the flange surface

6.1 Sealing elements for control block segments

Table 6: Sealing elements

Position Designation Use Dimension Number

O-ring Reservoir, return flow R 27 × 2.5 1

O-ring Inlet P 22 × 2.5 1

O-ring LS signal Y 18 × 2.5 1

O-ring Pilot oil return/supply Rx, X 9 × 2.5 2

Return flow, secondary
O-ring RfB 14 × 2.5 1
pressure relief valve

Flange surfaces Table 7: O-ring thickness – Flange surface protrusion

O-ring protrusion O-ring Ø d Protrusion X
1.5 mm 0.3 to 0.4 mm
2 mm 0.4 to 0.5 mm
2.5 mm 0.5 to 0.7 mm
3 mm 0.6 to 0.9 mm

Disassembly/assembly, 1. Remove the O-rings from the ports P, R, Y, Rx, X and RfB.
sealing elements 2. Insert new O-rings into the ports P, R, Y, Rx, X and RfB in the flange surface,
see Table 6.

Table 8: Disassembly/assembly, sealing elements

Flange surface Disassembly Assembly

Control block segments with a recess for an O-ring for Rx and X

(without continuous bore through the valve housing) must also be equipped
with O-rings.

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6.2 Repairing the shuttle valve

Table 9: Parts list

Position Designation
Shuttle valve

O-ring

Disassembly/assembly, 1. Remove the O-ring from port Y.

shuttle valve 2. Remove the shuttle valve from port Y.
3. Align the shuttle valve with the spherical sealing cup to port Y and insert
without jamming.
4. Check the distance dimension 0.5 mm from the flange surface of the
control block segment to the upper edge of the inserted shuttle valve.
5. Insert a new O-ring into port Y.

NOTICE! The shuttle valve must remain freely moveable within the O-ring .

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6.3 Repairing the spring pre-tensioned shuttle valve

Table 10: Parts list

Position Designation
Shuttle valve

O-ring

Conical compression spring (conical spring)

Disassembly/assembly, 1. Remove the O-ring from port Y.

spring pre-tensioned 2. Remove the shuttle valve from port Y together with the compression spring .
shuttle valve

3. Align the compression spring with the end side with the larger diameter
concentrically to the shuttle valve bore and insert it.
4. Push the compression spring in the shuttle valve bore down to the bore ground
while simultaneously turning it counter-clockwise.

Die compression spring is held at the bore ground by its form and tension.

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5. Align the shuttle valve with the spherical sealing cup to port Y and insert
without jamming.
6. Check the distance dimension 0.5 mm from the flange surface of the
control block segment to the upper edge of the inserted shuttle valve.
7. Insert a new O-ring into port Y.

NOTICE! The shuttle valve must remain freely moveable within the O-ring .

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Bosch Rexroth AG
Robert-Bosch-Straße 2
71701 Schwieberdingen
Germany
Phone +49 711 811-8481
info.ma@boschrexroth.de
www.boschrexroth.com

Your local contact person can be found at:

www.boschrexroth.com/addresses

Subject to change
Printed in Germany
RE 66170-11-R/2019-05-07