®

TUTHILL Drive Systems

TECHNICAL MANUAL

D705279 4/06

SELECTOR VALVE FLOW REGULATOR Patent Pending

Introduction

FORWARD This component technical manual contains necessary instructions to repair Selector Valves and Flow Regulators. This manual also includes theory of operation and testing procedures. Use this component technical manual in conjunction with the machine technical manual.

This is the Safety-alert symbol. When you see this symbol in this manual, be alert to the potential for personal injury.

MANUAL ORGANIZATION SECTION 00 – INTRODUCTION AND SAFETY SECTION 01 – GENERAL INFORMATION SECTION 02 – BILL OF MATERIALS

SECTION 03 – SELECTOR VALVE OPERATION SECTION 04 – FLOW REGULATOR OPERATION SECTION 05 – TROUBLE SHOOTING/TESTS

NOTE: MUD HOG® is a Registered Trade Mark of Tuthill Transport Technologies

Contents Page

Section 00 – Introduction and Safety Introduction 00-1 Safety 00-1 Emergencies 00-1 Lifting Equipment 00-1 Protective Clothing 00-1 High-Pressure Fluids 00-2 Work in Clean Area 00-2 Proper Tools 00-2 Fluid Disposal 00-2 Section 01 – General Information Selector Valve Identification 01-1 Flow Regulator Identification 01-1 Selector Valve Specifications 01-2 Flow Regulator Specifications 01-2 Selector Valve Dimensions 01-3 Flow Regulator Dimensions 01-3 Hydraulic Adapter Torque Values Metric/inch 01-4 Hydraulic Adapter Torque Values ORFS 01-5 Section 02 – Bill of Materials

Page Section 03 – Selector Valve Operation Low Pressure Shuttle, Forward 03-1 Low Pressure Shuttle, Reverse 03-1 Solenoid Valve 03-2 Principle of Operation 03-2 Selector Spool, Off 03-3 Selector Spool, On 03-4 Section 04 – Flow Regulator Operation Regulating Direction 04-1 Flow at Regulated Value 04-2 Return Direction 04-2 Section 05 – Trouble Shooting/Tests Trouble Shooting Checks 05-1 Trouble Shooting Chart 05-2 Trouble Shooting Chart Cont. 05-3 Test Procedure #1 05-4 Test Procedure #2 05-5 Test Procedure #3 05-6 Test Procedure #4 05-7

Selector Valve, Bill of Materials 02-1 Selector Valve, Exploded View 02-2 Flow Regulator, Bill of Material 02-3 All information, illustrations and specifications in this manual are based on the latest information available at the time of publication. The right is reserved to make changes at any time without notice.

I

Section 00 Introduction and Safety

INTRODUCTION This Technical Manual covers recommended repair procedures for Selector Valves and Flow Regulators. Before beginning repair, thoroughly clean external surfaces of valves since dirt and foreign material will damage critical surface finishes and seals if allowed to enter. Always use clean tools and work in a clean environment. RECOGNIZE SAFETY INFORMATION Pay special attention to this symbol. This is the safety alert symbol. Any time you see this symbol in this manual or on your machine be alert to the potential for personal injury. Follow recommended precautions and safe operating practices. Review the safety precautions. Read and familiarize yourself with this manual and the procedures involved before starting work. EMERGENCIES Be prepared for emergencies. Have a first aid kit and fire extinguisher available. Post emergency numbers near the telephone. Include numbers for ambulance service, fire department, hospital, doctor and poison control.

LIFTING EQUIPMENT Use appropriate equipment to left heavy components to avoid personal injury and equipment damage. Follow instructions for attachment and removal of equipment in manual.

CLOTHING Wear appropriate clothing and safety equipment for the job. Protect your ears from loud noises to avoid hearing loss.

00-1

Introduction and Safety/Avoid High Pressure Fluids

HIGH-PRESSURE FLUIDS Stay away from high-pressure leaks. High-pressure leaks can cause serious injury. Avoid injuries by relieving pressure before disconnecting hydraulic or other lines. Tighten all connections before applying pressure. Use cardboard to check for leaks. If fluid penetrates your skin, contact a doctor immediately. Fluid must be removed immediately to avoid gangrene. CLEAN WORK AREA Keep work area and machine clean. Have necessary tools and parts organized and readily available. Read instructions thoroughly and have instructions within reach. TOOLS Avoid personal injury and damage to tools and parts by using the correct tool for the task. FLUID DISPOSAL Contact your local environmental agency to get instructions on proper fluid disposal before draining any fluids. Do not use food or beverage containers to hold fluids. Do not pour any fluids into the ground, a drain, lake, pond, etc.

00-2

Serial Number Build Date

Section 01 General Information

SELECTOR VALVE IDENTIFICATION Each Selector Valve has a Serial Number and a build Date stamped in the side of the valve body.

FLOW REGULATOR IDENTIFICATION Each Flow Regulator shows the direction of regulated flow and has a flow rate (gpm) stamped in the outer housing. (Text may be different than shown)

01-1

Direction of Regulated Flow Flow Rate

General Information/Specifications

SELECTOR VALVE SPECIFICATIONS Type Flow Rate Max. Operating Pressure Cartridge Valve

4-way, 2-position 1 spool, Pilot operated 63 gpm Nominal 238 lpm 6500 psi 450 bar 3-way, 2-position 12 VDC Solenoid

FLOW REGULATOR SPECIFICATIONS Type Flow Rate Max. Operating Pressure

Pressure Compensated Flow Control Free Flow Return 15 - 40 gpm 57-152 lpm 6500 psi 450 bar

01-2

General Information/ Dimensions

SELECTOR VALVE DIMENSIONS

FLOW REGULATOR DIMENSIONS

01-3

General Information/Hydraulic Adapter Torque Chart

HYDRAULIC ADAPTER TORQUE VALUES DO NOT use these values if a different torque or tightening procedure is listed for a specific application. Torque values listed are for general use only. Make sure adapters are clean and you properly start threaded engagement. This will prevent them from failing when tightened. TABLE 1: METRIC PORT THREAD SAE J2244-2/ISO 6149-2 metric straight thread o-ring port connector recommended torque levels for use with SAE J1453/ISO 8434-3 ORFS connectors.

Thread Size

Nominal Tube OD

mm

Assembly Torque (Into Steel)

Nm M10x1 5 20 - 22

M12x1.5 6 35 - 39 M14x1.5 8 45 - 50 M16x1.5 10 55 - 61 M18x1.5 12 70 - 77 M22x1.5 16 100 - 110 M27x2 20 170 - 187 M30x2 22 215 - 235 M33x2 25 310 - 341 M42x2 32 330 - 363 M48x2 38 420 - 462 M60x2 50 500 - 550

TABLE 2: INCH PORT THREAD SAE J1926-2 inch straight thread o-ring port connector recommended torque levels for use with SAE J1453/ISO 8434-3 ORFS connectors.

Thread Size

SAE DashSize

Assembly Torque(Into Steel)

Nm. 3/8-24 -3 10 - 12 7/16-20 -4 20 - 22

½-20 -5 25 - 28 9/16-18 -6 33 - 35

¾-16 -8 68 - 78 7/8-14 -10 98 - 110

1-1/16-12 -12 170 - 183 1-3/16-12 -14 215 - 245 1-5/16-12 -16 270 - 300 1-5/8-12 -20 285 - 380 1-7/8-12 -24 370 -490

01-4

General Information/Hydraulic Adapter Torque Chart HYDRAULIC ADAPTER TORQUE VALUES Cont. TABLE 3: ORFS CONNECTIONS SAE J1453/ISO 8434-3 o-ring face seal connectors recommended torque levels for ORFS tube assemblies, hose assemblies and connectors.

English Dash Size

Thread AssemblyTorque

Nm -4 9/16-18 14 – 16* -6 11/16-16 24 – 27* -8 13/16-16 43 – 47*

-10 1-14 60 - 68 -12 1-3/16-12 90 - 95 -16 1-7/16-12 125 - 135-20 1-11/16-12 170 - 190-24 2-12 200 - 225

* Torque level shown is for maximum pressure rating of 42MPa.

01-5

Section 02 Bill of Materials

Parts List for Selector Valve Assembly

Item Qty Description

1 1 Solenoid, 12V W/wire Leads

2 1 Connector

3 2 Pin, Terminal

4 5 Plug, 02 ORB-M Hex Socket Head

5 3 Plug, 04 ORB –M Hex Socket Head

6 2 Seal

7 1 Forward Adapter

8 1 Drain Adapter

9 1 Plug, M33

10 2 Check Ball

11 2 Roll Pin

12 1 Spool

13 1 Valve Body, Machined

14 1 Spring

15 1 Reverse Adapter

16 1 Dowel Pin

17 4 Flow Regulator

18 1 Seal Kit

02-1

Bill of Material/Selector Valve Selector Valve

02-2

Bill of Material/Flow Regulator

Parts List for Flow Regulator Assembly

Item Qty Description

1 1 Body, Flow Regulator, M33

2 1 Baffle, Flow Regulator

3 1 Piston, Flow Regulator

4 1 O-Ring M33 Boss

5 1 Spring

6 1 Washer, Hardened

7 1 Adapter, M33

Flow Limiter

02-3

PF

B

Dowel Pin

A

C

PR

System Pressure

Charge Pressure

PF

B

A

C

PR

Section 03 Selector Valve Principle of Operation

LOW PRESSURE SHUTTLE (FORWARD) The low-pressure shuttle system of the Selector valve is a combination of two check valves between the forward and reverse sides of the hydrostatic circuit, ahead of the selector spool. The shuttle system provides pilot (control) pressure oil to passage A at all times; even when the MUD HOG® is off. Passage A feeds to the solenoid cartridge valve which directs charge pressure oil to engage the selector spool. There is always charge pressure on the return side of the hydrostatic circuit; for example, in the forward operating mode there is system pressure oil in the pump forward (PF) cavity and charge pressure oil in the pump reverse (PR) cavity. In this situation, the system pressure will be higher than the charge pressure. In forward operation system pressure oil will close off check ball B. When B closes off, check ball C will open up due to the dowel pin between balls B and C. This pin will not allow both balls to seat at the same time. When check ball C opens, this allows charge pressure oil to flow from the return (reverse) side of the circuit, past the check ball C, past the spacer and into passage A. LOW PRESSURE SHUTTLE (REVERSE) In the reverse operating mode there is system pressure oil in the pump reverse (PR) cavity and charge pressure oil in the pump forward (PF) cavity. System pressure oil will close off check ball C. When C closes off, check ball B will open up due to the dowel pin between balls B and C. This pin will not allow both balls to seat at the same time. When check ball B opens, this allows charge pressure oil to flow from the forward side of the circuit, past the check ball B, past the spacer and into passage A.

03-1

System Pressure

Charge Pressure

To TankCharge Pressure From Low Pressure Shuttle

DrainS

Charge Pressure

Selector Spool In Off PositionTo Tank

Charge Pressure From Low Pressure Shuttle

SDrain

Charge Pressure

Selector Spool In On Position

Spool in OnPosition

Spool in Off Position

Selector Valve Operation/Solenoid Valve

SOLENOID VALVE The solenoid valve is a 3-way valve that takes the charge pressure oil and directs it to passage S of the selector spool when the MUD HOG® is turned “ON”. When the MUD HOG ® is turned off the charge pressure is blocked internally in the solenoid valve and cavity S of the selector spool is connected to tank.

The MUD HOG® High Capacity Selector valve is designed for use on machines having nominal flow rates greater than 60 gpm to the rear wheel assist drives. The valve is a spool type valve incorporating ON-OFF control of the assist axle and can be equipped with optional flow regulators for improved traction control when required. An ON-OFF switch in the operator’s cab activates the electric solenoid valve. The solenoid valve directs pilot pressure to move the selector spool. This movement of the spool opens up internal passages within the valve to permit high system pressure oil to flow to the wheel motors. The oil flow is split between the wheel motors. When the selector valve solenoid is not activated, high- pressure oil flow is blocked and all motor and valve cavities are connected to tank. For better control of the high-pressure oil flow, optional flow regulators can be installed.

03-2

Selector Valve Operation/Solenoid Valve SELECTOR SPOOL (OFF POSITION) With the MUD HOG® system off, charge pressure oil in the Selector valve is blocked at the solenoid valve. Cavity S is exposed to tank through the solenoid cartridge. The spring pressure in cavity D holds the spool in the OFF position. The spool prevents system pressure oil from entering both the forward or reverse inlet port and the rest of the valve; therefore no high-pressure oil is delivered to the wheel motors. In the off position the spool cavities PF and PR are closed off from motor cavities MF and MR. Cavities PF and PR are the forward and reverse pressure inlet cavities; they will always be exposed to either system pressure or return (charge) pressure oil depending on direction of the machine. Cavity MF opens an oil flow path to the forward pressure ports of the wheel motors. Cavity MR similarly opens an oil flow path to the reverse pressure ports of the motors.

03-3

S

System Pressure

Spool In OffPosition

PF

MF

MR

PR

Spring

D

Drain

Charge Pressure

Selector Valve Operation/Selector Spool SELECTOR SPOOL (ON POSITION) When the switch in the cab is in the ON position, the coil within the solenoid valve is energized. Passages in the solenoid valve cartridge are opened and charge pressure oil is delivered to cavity S and shifts the spool, compressing the spring in cavity D. When the spool arrives at its full ON position, passage PF is open to passage MF, which provides forward system pressure to the forward pressure inlet ports of the motors. Passage MR is open to passage PR, which allows return flow (at charge pressure) to come from the motors and back to the return side of the hydrostatic circuit. In the reverse operation mode, the process is switched; where passages MR and PR are open to each other to provide reverse system pressure to the reverse pressure inlet ports of the motor. Passages PF and MF allow return flow to come from the motors.

03-4

S

Drain

System Pressure

Charge Pressure

D

PR

MR

MF

PF

Spool In On Position

OIL TO MOTOR

OIL FROM PUMP

The space between matingedges of spool and baffle

comprise a variable orificeFixed reference orifice in end of sliding spool

REGULATED DIRECTION (FORWARD) SHOWN; REVERSE OPPOSITE

Section 04 Flow Regulator Operation

FLOW REGULATOR * The Flow Regulator purpose is to limit maximum flow to a wheel drive motor due to the loss of traction. The normal result of losing traction is wheel spin out at the affected wheel. The effect of this is that the speed of the spinning motor can increase to the limit of available system flow. The torque is lost at other wheels due to pressure reduction in the system. The Flow Regulator mounts in the hydraulic line to a wheel motor, and controls only the flow to that motor or axle in one direction of rotation. Free flow is permitted in the opposite direction, and allows a second regulator valve to separately control flow in the opposite direction. *Patent Pending Flow Regulator in normal operating mode at a flow level below regulated value.

04-1

As flow rate through the valve approaches controlled value, the spool and baffle compress the spring reducing the flow path to control the flow rate. The valve constantly modulates to maintain constant flow at the design reference value.

Flow Regulator Operation

Flow at Regulated Value

Return Direction

04-2

When flow returns in the reverse direction, the spool slides freely to the right. The spool will extend past the end of the body and allows for additional orifices to open. This allows for free flow return through the flow regulator.

Section 05 Trouble Shooting/Tests

Trouble Shooting Checks With the engine of the machine shut off, check for evidence of external oil leakage around seals, housing or hose connections. Also check for pinched or kinked hoses and steel lines that could restrict oil flow and cause excessive heat build-up in the hydraulic oil. Check hydraulic oil level in reservoir and add the correct amount and type of hydraulic oil, if necessary. Check the quality of the oil; change if milky, dirty or discolored. Also smell the oil. A burned odor indicates excessive heat that can destroy the lubricating qualities of the oil. Again, the oil should be changed if this condition is found. Determine the cause of the excessive heat and correct it. Determine if the hydrostatic filter is plugged or damaged. A filter that has failed will permit oil to bypass the system, affecting system operation and tests. Check the maintenance records with the machine to determine if the recommended service procedures have been made at the proper intervals. Check for previous reports of unusual, frequent or similar failures.

05-1

Trouble Shooting/Tests/Test Procedure #1

Trouble Shooting

05-2

PROBLEM POSSIBLE CAUSE REMEDY A) Operating with transmission

gearing too low System is more effective in

higher gear.

B) Incorrectly plumbed main high pressure lines (For. & Rev)

Refer to MUD HOG® Installation/Operation Manual for

correct plumbing procedure. C) Weak high pressure relief

valve Refer to machine service manual

for proper setting. D) Excessive case leakage from

MUD HOG® system: 1) From wheel motor(s)

2) From selector valve

See test Procedure # 1, page 05-4

1) Performance of RWD is sluggish (poor)

E) Inadequate charge pressure See Test Procedure # 1 page 05-4

2) RWD operates in Forward but not in Reverse OR operates in

Reverse but not in Forward

A) Excessive Case Leakage

B) Electrical circuit malfunction

C) Stuck spool in selector valve

See Test Procedure # 1 page 05-4

Trouble Shooting/Tests/Test Procedure #2 & #3

Trouble Shooting, Cont.

05-3

PROBLEM POSSIBLE CAUSE REMEDY A) Incorrectly mounted high pressure hoses on hydraulic

wheel motors

Refer to MUD HOG® Installation/Operation Manual for

proper hose routing.

3) One wheel on RWD is dragging or locked up

B) Hydraulic wheel motor is locked up due to internal

component failure.

With the MUD HOG® system “OFF” (no Forward or Reverse system pressure) and with the

tire off the ground, rotate tire by hand, if the tire will not rotate, then the wheel motor is locked up. Service or replace wheel

motor. A) Blown fuse. Replace fuse.

B) ON-OFF switch shorted out.

Replace switch.

C) Disconnected or broken electrical wire.

Reconnect or replace with16 gauge wire.

D) Solenoid valve in selector valve not working due to:

1) Solenoid valve spool not shifting.

2) Coil inside solenoid valve shorted out.

3) Lose wire connections(s)

4) Improper grounding.

See Test Procedure # 2 page 05-5

4) RWD is not functioning.

E) Main spool in selector valve not shifting.

F) Excessive motor leakage.

G) Low hydrostatic fluid level.

See Test Procedure # 3 page 05-6

Trouble Shooting/Tests/Test Procedure #2

Test Procedure #1 Problem/Cause – Rear Wheel Drive Sluggish/Excessive Leakage/Inadequate Charge Pressure Make sure that the outside of the Selector valve is free from any dirt or grease. Dirt must NOT be allowed to enter the valve when removing any of the valve components. CAUTION The following steps require removal of hydraulic hoses and fittings. Be sure to relieve pressure from system prior to loosening any connections. Install 7500 psi (or greater) pressure gauges in both the forward and reverse inlet hoses to the valve. Install 500 psi (or greater) pressure gauge in charge pressure port and drain test port. With Rear Wheel Drive “ON”, record pressure readings with machine moving in forward and then reverse. Sluggish (poor) performance of machine may be caused when charge pressure drops below 100 psi, when this happens system pressure is not allowed to increase high enough to keep the machine moving. Leakage from the selector valve should not exceed 2 gallons per minute (gpm) with the machine moving at system pressure.

1) Disconnect hose end from bottom fitting on valve.

2) Plug hose 3) Measure leakage from bottom fitting. Note: Flow may pulse when shifting valve.

Leakage from the wheel motors will vary depending on the size and type of motor. In general, leakage should not exceed 2.0 gpm from each motor. If excessive leakage exists, refer to the appropriate motor technical manual for your machine. If leakage is within specification, then components with the hydrostatic transmission of the machine may have excessive leakage; refer to the service manual for the machine.

05-4

Charge Pressure Test Ports

Drain Test PortPressure should be zero at

this port. (Pressure may pulse when shifting). If

pressure doesn’t drop to zero drain hose or passage

may be obstructed.

Disconnect and plug hose

Solenoid Coil

Wire Leadsfrom Coil

Seals

Pin Terminals

Wire Connector

Trouble Shooting/Tests/Test Procedure #2

Test Procedure #2 Problem/Cause – Rear Wheel Drive NOT Functioning/Solenoid Valve Not Working Turn Ignition switch to “ON” position or machine configuration that allows signal voltage to the rear wheel drive without starting engine. Have assistant operate the ON-OFF Rear Wheel Drive switch. A distinct “click” should be heard at the solenoid, indicating that the solenoid valve spool is shifting properly. If “click” is not heard, check for possible loose wire connections at the solenoid, switch in the cab and all other connections for rear wheel assist harness. If no problems are found, perform an electrical resistance check on the solenoid valve coil to determine if the coil is defective. Coil resistance should be 7 - 9 ohms. If all electrical connections are good and coil resistance is good, replacement of the solenoid valve is necessary.

05-5

Charge Pressure Test Ports

Drain Test Port

Spring

Fitting

Disconnectand plug hose

Spool

Trouble Shooting/Tests/Test Procedure #3

Test Procedure #3 Problem/Cause – Rear Wheel Drive NOT Functioning/Selector Spool NOT Shifting Make sure that the outside of the Selector valve is free from any dirt or grease. Dirt must NOT be allowed to enter the valve when removing any of the valve components. Caution The following steps require removal of hydraulic hoses and fittings. Be sure to relieve pressure from system prior to loosening any connections. Install 7500 psi (or greater) pressure gauges in the forward and reverse inlet lines to the valve and forward and reverse lines between the Selector valve and the wheel motors. Install 500 psi (or greater) pressure gauges in the charge pressure port and drain test port. With Rear Wheel Drive “ON”, record pressure readings with machine moving in forward and then reverse. With Rear Wheel Drive “OFF”, record pressure readings with machine moving in forward and then reverse. If pilot pressure reading is NOT correct, (machine charge pressure) then check solenoid valve to be sure that the valve is shifting properly (See Test Procedure #2). If pilot pressure reading is correct, but the forward and reverse line pressures to the wheel motors are NOT correct, then the main spool in the Selector valve is not shifting. Forward and reverse pressures will be the same as the machine system pressure and machine charge pressure. To prevent siphoning of the oil reservoir, loosen and remove the bottom hose connection from the valve. Plug the hose to prevent draining the reservoir. Remove bottom fitting from Selector valve. Check for free movement of Selector spool in the bore. If spool does not move freely, remove spool from bore and check for excessive wear on the spool and the bore. Reinstall spool in bore and check again for free movement. If spool continues to stick, replacement of the complete Selector valve is necessary.

05-6

Adapter

Baffle

Spring

Washer

Piston

Body

O-Ring

Trouble Shooting/Tests/Test Procedure #4

Test Procedure #4 (For optional Flow Regulators) Problem/Cause – Rear Wheel Drive is Sluggish Make sure that the outside of the Selector valve and Flow Regulators are free from any dirt or grease. Dirt must NOT be allowed to enter the system when removing any of the valve/flow regulator components. Caution The following steps require removal of hydraulic hoses and fittings. Be sure to relieve pressure from system prior to loosening any connections. Install 7500 psi (or greater) pressure gauges in the forward and reverse inlet lines to the valve and forward and reverse lines between the Selector valve and the wheel motors. Install 500 psi (or greater) pressure gauges in the charge pressure port and drain test port. With Rear Wheel Drive “ON”, record pressure readings with machine moving in forward and reverse. With Rear Wheel Drive “OFF”, record pressure readings with machine moving in forward and then reverse. If pilot pressure reading is NOT correct, (machine charge pressure) check solenoid valve to be sure that the valve is shifting properly (See Test Procedure #2, page 05-5). If pilot pressure reading is correct, but the forward and reverse line pressures to the wheel motors are NOT correct, check the selector spool to be sure that the spool is shifting properly (See Test Procedure #3, page 05-6). If the solenoid valve and the spool are shifting properly, then the flow regulators may not be functioning properly. To prevent siphoning of the oil reservoir, loosen and remove the bottom hose connection from the valve. Plug the hose to prevent draining the reservoir. Remove the hoses from the flow regulators and the flow regulators from the Selector valve. Check for free movement of piston in the bore of the flow regulator. If piston does not move freely, remove piston, spring, washer and baffle from flow regulator by removing hydraulic adapter. Check all parts and bore for excessive wear. Reinstall spool in bore and check again for free movement. If spool continues to stick, replacement of the Flow Regulator is necessary.

05-7

Charge Pressure Test Ports

Drain Test Port

Disconnectand plug

hose