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Introduction
| Revision | Summary of Changes in REHS2553 |
| 21 | Added new serial number prefixes. |
| 20 | Added new serial number prefixes. |
| 19 | Added new serial number prefixes. |
| 18 | Added new serial number prefixes |
| 19 | Added new serial number prefixes |
© 2018 Caterpillar All Rights Reserved. This guideline is for the use of Cat Dealers only. Unauthorized use of this document or the proprietary processes therein without permission may be violation of intellectual property law. Information contained in this document is considered Caterpillar: Confidential Yellow.
This guideline enables dealers and dealer customers to benefit from cost reductions made possible through an established parts reusability and salvage program. Every effort has been made to provide the most current information known to Caterpillar Inc. Since the company makes ongoing product changes and product improvements, this guideline must be used with the latest technical information. Using the latest technical information available from Caterpillar ensures that such changes and improvements are incorporated where applicable.
For questions or additional information concerning this guideline, submit a feedback form in the Service Information System web site. To address an urgent need, use the following to forward your request to Caterpillar Repair Process Engineering:
- Cat Dealer Technical Communicator
- Global Dealer Solution Network
- Cat Technical Representative
- Knowledge Network
Canceled Part Numbers and Replaced Part Numbers
This document may include canceled part numbers and replaced part numbers. Use NPR on SIS for information about canceled part numbers and replaced part numbers. NPR will provide the current part numbers for replaced parts.
Summary
This guideline describes how to determine if a hydraulic cylinder position sensor can be reused or should be replaced.
The guideline includes illustrations of hydraulic cylinder position sensors which can/cannot be used again, with/without salvage operations.
Never install a part that this guideline shows cannot be used again. Also, during salvage operations, always correct any conditions that caused the original failure or wear.
Important Safety Information
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| Illustration 1 | g02139237 |
Most accidents that involve product operation, maintenance, and repair are caused by failure to observe basic safety rules or precautions. An accident can often be avoided by recognizing potentially hazardous situations before an accident occurs. A person must be alert to potential hazards. This person should also have the necessary training, skills, and tools to perform these functions properly.
Improper operation, lubrication, maintenance, or repair of this product can be dangerous and could result in injury or death.
Do not operate or perform any lubrication, maintenance, or repair on this product, until you have read and understood the operation, lubrication, maintenance, and repair information. Safety precautions and warning are provided in this manual and on the product. If these hazard warnings are not heeded, bodily injury or death could occur to you or to other persons.
The hazards are identified by the "Safety Alert Symbol" and followed by a "Signal Word" such as "WARNING" as shown below.
The meaning of this safety alert symbol is as follows:
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Attention! Become Alert! Your safety is involved. |
The message that appears under the warning explains the hazard and can be either written or pictorially presented.
Operations that may cause product damage are identified by "NOTICE" labels on the product and in this publication.
| NOTICE |
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Notice labels in this publication identify operations that may cause product damage. |
Caterpillar cannot anticipate every possible circumstance that might involve a potential hazard. The warnings in this publication and on the product are, therefore, not all inclusive. If a tool, procedure, work method, or operating technique that is NOT recommended by Caterpillar is used, be sure that the tool or process is safe for everyone. Also ensure that the product will not be damaged or be made unsafe by the operation, lubrication, maintenance, or repair procedures that you choose.
The information, specifications, and illustrations in this publication are based on information that was available at the time that the publication was written. The specifications, torque, pressures, measurement, adjustments, illustrations, and other items can change at any time. These changes can affect the service that is given to the product. Contact your Cat dealer to obtain complete information and the most current information available before you start any job.
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Do not operate or work on this product unless you have read and understand the instructions and warnings in the Operation and Maintenance Manual. Failure to follow the instructions or heed the warnings could result in injury or death. Contact any Caterpillar dealer for replacement manuals. Proper care is your responsibility. |
Safety
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Sudden movement of the machine or release of oil under pressure can cause injury to persons on or near the machine. To prevent possible injury, perform the procedure that follows before testing and adjusting the steering system. |
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Personal injury can result from hydraulic oil pressure and hot oil. Hydraulic oil pressure can remain in the hydraulic system after the engine has been stopped. Serious injury can be caused if this pressure is not released before any service is done on the hydraulic system. Make sure all of the attachments have been lowered, oil is cool before removing any components or lines. Remove the oil filler cap only when the engine is stopped, and the filler cap is cool enough to touch with your bare hand. |
| NOTICE |
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Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting, and repair of the product. Be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component containing fluids. Refer to Special Publication, NENG2500, "Dealer Service Tool Catalog" for tools and supplies suitable to collect and contain fluids on Cat® products. Dispose of all fluids according to local regulations and mandates. |
References
| References | |
|---|---|
| SEHS9615 | "Servicing Deutch HD and DT Style Connectors" |
| NEHS0678 | "146-4080 Digital Multimeter (Operation Manual)" |
| NENG2500 | "Dealer Service Tool Catalog" |
| NEHS0993 | "276-7273 Cylinder Sensor Test Box (In Cylinder Function Test)" |
Tooling and Equipment
Note: The list of machines and tooling is a recommended list.
| Required Tools | |
|---|---|
| Part Number | Part Description |
| 146-4080 | Digital Multimeter Group |
| 10 V Power Supply
9 - 12 V Battery |
|
| 8T-0447 | Dial Caliper |
| 276-7273 | Test Box |
Sensor Identification and Specifications
The sensor that is described in this guideline is a Class 2 sensor.
Table 4 shows some dimensions of the sensor and the range of frequency for the sensor. Table 4 also shows what the markings on the housing should look like on a Class 2 sensor. Example: A Class 2 sensor will have a marking on the side such as CAT21548.
| Sensor Identification | ||||
|---|---|---|---|---|
| Class | Pressure Pipe
Diameter |
Housing Length | Housing
Markings |
Freq.
(Hz) |
| 2 | |
|
CAT2 | 100-130 |
Pressure Pipe
| |
| Illustration 2 | g01141369 |
|
Pressure Pipe is straight and clean. Use again | |
The sensor shown has a shortened pressure pipe. In all actuality, the pressure pipe would be much longer. Refer to Illustration 2.
The pressure pipe should be clean and straight to be used again.
| |
| Illustration 3 | g01141373 |
|
Bent or kinked pressure pipe. Do not use again | |
Illustration 3 is a drawing of what a bent or kinked pressure pipe would be. (Not To Scale.)
If a pressure pipe is bent or kinked, do not use again.
Pressure Pipe Checklist
| Pressure Pipe Checklist | ||
|---|---|---|
| OK - Use Again | Not OK-Replace | |
| Straightness | Not bent and no kinks | Pressure pipe is bent or kinked
High spots greater than |
| Wear | No excessive wear | Pressure pipe diameter is wore more than |
| Cracks, Holes, Splits | None | There is a crack, hole, or split |
| Dents | None | There are dents of any size in the pressure pipe. |
| (1) | Roll the sensor 360° and look for high spots in the pressure pipe. |
| (2) | Wear will be slightly greater at the end of the pressure pipe because of droop and sag |
| (3) | Wear may be an indication that the pressure pipe is bent |
Sensor Housing
| |
| Illustration 4 | g01141438 |
|
Sensor Housing Use Again | |
The sensor housing is contamination free, dent free, corrosion free, and there is no damage to the O-ring groove. The sensor housing is OK to use again. Refer to Illustration 4.
Sensor Housing Checklist
| |
| Illustration 5 | g01141450 |
|
Use again | |
The sensor housing is free of any weld/braze defects, dent free, corrosion free, and there is no damage to the O-ring groove. The sensor housing is OK to use again. Refer to Illustration 5.
| Sensor Housing Checklist | ||
|---|---|---|
| OK - Use Again | Not OK-Replace | |
| Cracks or dents in housing | None | Housing cracked or dented. |
| Cracks or dents in housing boss | None | Housing cracked or dented. |
| Scratches, Gouges, and Wear | No excessive wear(1) | None |
| Weld/braze Joint(2) | Not split or cracked. Refer to Illustration 5 | Weld/brazed joint is cracked or split |
| (1) | If scratches, gouges, and wear do not affect the roundness of the sensor – clean and use again |
| (2) | Check weld/braze joint integrity connecting boss to housing and pressure pipe to boss |
Magnet
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| Illustration 6 | g01141473 |
|
A good magnet Use Again | |
Magnet Checklist
| Magnet Checklist | ||
|---|---|---|
| OK - Use Again | Not OK-Replace | |
| Cracks | None | Magnet is cracked. |
| Chips | None | Magnet is chipped. |
| Wear | No excessive wear | If any sign of wear on magnet or protective coating. Refer to Illustration 7 |
| |
| Illustration 7 | g01141480 |
|
The magnet on the left shows no sign of wear so the magnet can be reused. The magnet on the right shows signs of wear and should be replaced. The wear may be caused by a bent rod or contamination in the cylinder. | |
Deutch Receptacle
The Deutch receptacle is a piece that can be changed without replacing the sensor.
If the receptacle is smashed or cracked, replace the receptacle.
If any of the pins are missing, bent, or damaged, replace the receptacle.
The receptacle and pins can be purchased separate from each other. With the Receptacle Kit (P/N 102-8804) you receive the receptacle and the pin-retaining wedge.
If a pin has to be changed, make sure to cut as little wire off as possible. If too much wire is cut off, and the Deutch receptacle will not slide into the mount on the mounting plate, replace the sensor.
Wires
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| Illustration 8 | g01141514 |
|
The wires should be in clean and crack free. Use Again | |
Illustration 8 shows the wires running from the sensor housing to the connector pins.
If a wire is broken, replace the sensor.
The wire, under some situations, may be repaired and reused. If the break is close to the connector end of the wire, soldering the wire together may be possible. Once soldered, apply heat shrink tubing to cover the solder joint. Do not repair the wire if the break is close to where the grommet fits on the wire. If the wire has a splice in this area, the wire will not have a correct fit around the grommet. Water would leak in. Do not make the splice too large. When the sensor is installed, the wires have to fit through a small 90 degree corner in the back of the cylinder. If the splice is too large, pulling the wires around this corner will be difficult.
If the wire is repaired, be sure to check that the electronics of the sensor were not affected and are still working correctly.
Note: Do NOT use a butt splice to repair a wire in this situation because of the small clearance the wire must fit through.
If the insulation is cracked, repair the insulation and use the sensor again.
Caution must be taken to ensure that the repair still allows the wires to slide through the slot in the back of the cylinder.
Wire Sleeve
| |
| Illustration 9 | g01141535 |
The wire sleeve is important. The wire sleeve protects the wires inside the cylinder from wear caused by the cylinder walls due to vibrations and movement. Refer to Illustration 9.
Check for cuts, chaff marks, and spots that are worn through on the wire sleeve. If there is any sign of these flaws, replace the wire sleeve.
Plug/Wire Protection Cover
| |
| Illustration 10 | g01141536 |
|
Plug/Wire Protection Cover | |
| Plug/Wire Protection Cover Checklist | ||
|---|---|---|
| Check For: | OK - Use Again | Not OK-Replace |
| Damage | None | Cover is smashed. |
| Scratches | Cover is scratched | None |
| Corrosion | Cover is corroded(1) | None |
| (1) | Clean and paint to use again. |
Grommet
| |
| Illustration 11 | g01141555 |
Illustration 11 shows the grommet that prevents contamination from getting into sensor area.
| Plug/Wire Protection Cover Checklist | ||
|---|---|---|
| Check For: | OK - Use Again | Not OK-Replace |
| Cracks | Not cracked or split | Grommet is cracked or split |
| Deformity | Not deformed | Grommet is deformed. |
| Hard or Brittle | Not brittle or hard | Grommet is hard or brittle. |
| Seal(1) | Seal is OK | Seal is not tight. |
| (1) | Check for tight seal between grommet and cylinder housing and between grommet and wires. |
Sensor Seal – O – ring
| |
| Illustration 12 | g01141573 |
|
Sensor seal-o-ring | |
Caterpillar recommends that the seal-O-ring is replaced every time the sensor is removed.
Sensor Backup Ring
| |
| Illustration 13 | g01141576 |
|
Back up ring | |
Caterpillar recommends that the backup ring is replaced every time the sensor is removed.
Mounting Plate
| |
| Illustration 14 | g01141587 |
|
Mounting plate | |
If the plate is damaged to a point where the plate will not allow a clean seal to the cylinder housing, replace the plate.
If the plate is only scratched, use the plate again.
Clean the plate and use the plate again if there is corrosion on the plate.
Note: This plate is often hard to get off due to the glue that is used on the backside during installation.
Sensor Signal
To measure the sensor signal, use a multimeter with a 10V power supply (a 9-12V battery can also be used). Use the voltage reading to determine the following:
Replace the sensor if the signal goes high and stays high 5V.
Replace the sensor if the signal output is intermittent.
Replace the sensor is the signal is 0V.
Duty Cycle
Duty Cycle is a ratio of pulse width to the time between pulses. The pulse wave is a square wave instead of a curved wave. The duty cycle reading will be a whole number 0 – 100 which corresponds to a percent.
To test for the duty cycle, use a multimeter and a 10V power supply. Connect the 10V power supply to the orange wire and connect the multimeter to the white wire. The black wire is the ground wire. With the sensor out of the cylinder, place a magnet in the middle of the pressure pipe. The percent duty cycle reading should be within the 5-50% range. Also the percent duty cycle should increase as the magnet is slid along the pressure pipe away from the sensor housing.
Note: A 9-12V battery can also be used.
Replace the sensor if the percent duty cycle is not within the 5-50% range when the magnet is in the middle of the pressure pipe.
Replace the sensor if the percent duty cycle does not increase as the magnet is slid along the pressure pipe away from the sensor housing.
Resistance Check
Measure the pin to pin resistance with a multimeter set on the ohms setting.
Do not apply a power supply voltage or battery to any pin.
Replace the sensor if the resistance between any two of the three pins is less than 100,000 ohms (100K ohms)
Frequency Check
To check the frequency of the sensor, place the multimeter on the Hz setting. Use a 10V power supply or a 9-12V battery to provide power.
Replace the sensor if the sensor does not display a frequency of 100 –130 Hz.