Specifications for Reusability of the 251-7646 Fan Drive Bracket Assembly on 3500 Machine Engines {1359} Caterpillar


Specifications for Reusability of the 251-7646 Fan Drive Bracket Assembly on 3500 Machine Engines {1359}

Usage:

793B 1HL
Caterpillar Products
All 3500 Engines
All G3500 Engines

Introduction

Table 1
Revision  Summary of Changes in SEBF9177 
15  Added new serial number prefixes for New Product Introduction (NPI). 

© 2019 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 Reuse and Salvage Guideline contains the necessary information to allow a dealer to establish a parts reusability program. Reuse and salvage information enables Caterpillar dealers and customers to benefit from cost reductions. Every effort has been made to provide the most current information that is known to Caterpillar. Continuing improvement and advancement of product design might have caused changes to your product which are not included in this publication. This Reuse and Salvage Guideline must be used with the latest technical information that is available from Caterpillar.

For technical questions when using this document, work with your Dealer Technical Communicator (TC).

To report suspected errors, inaccuracies, or suggestions regarding the document, submit a form for feedback in the Service Information System (SIS Web) interface.

Canceled Part Numbers and Replaced Part Numbers

This document may not 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.

Important Safety Information



Illustration 1g02139237

Work safely. 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. Safety precautions and warnings are provided in this instruction and on the product. If these hazard warnings are not heeded, bodily injury or death could occur to you or to other persons. Caterpillar cannot anticipate every possible circumstance that might involve a potential hazard. Therefore, the warnings in this publication and the warnings that are on the product are not all inclusive. If a tool, a procedure, a work method, or operating technique that is not recommended by Caterpillar is used, ensure that it is safe for you and for other people to use. Ensure that the product will not be damaged or the product will not be made unsafe by the operation, lubrication, maintenance, or the repair procedures that are used.

Safety precautions and warnings 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 which is followed by a signal word such as danger, warning, or caution. The "WARNING" safety alert symbol is shown below.



Illustration 2g00008666

This safety alert symbol means:

Pay attention!

Become alert!

Your safety is involved.

The message that appears under the safety alert symbol explains the hazard.

Operations that may cause product damage are identified by "NOTICE" labels on the product and in this publication.

Caterpillar cannot anticipate every possible circumstance that might involve a potential hazard. The safety information in this document and the safety information on the machine are not all inclusive. Determine that the tools, procedures, work methods, and operating techniques are safe. Determine that the operation, lubrication, maintenance, and repair procedures will not damage the machine. Also, you must determine that the operation, lubrication, maintenance, and repair procedures will not make the machine unsafe.

The information, the specifications, and the illustrations that exist in this guideline are based on information which was available at the time of publication. The specifications, torques, pressures, measurements, adjustments, illustrations, and other items can change at any time. These changes can affect the service that is given to the product. Obtain the complete, most current information before you start any job. Caterpillar dealers can supply the most current information.

Summary

This guideline applies to the inspection of the used 251-7646 Fan Drive Bracket Assembly. The inspection will be used to determine if the fan drive bracket assembly can be used again. If the fan drive bracket meets the specifications in this guideline and other applicable guidelines, the bracket can be expected to provide normal performance until the next overhaul. However, the fan drive bracket must be used again in the same application.

Service Letters and Technical Information Bulletins


NOTICE

The most recent Service Letters and Technical Information Bulletins that are related to this component shall be reviewed before beginning work. Often Service Letters and Technical Information Bulletins contain upgrades in repair procedures, parts, and safety information that pertain to the parts or components being repaired.


Tooling and Equipment

Table 2
Required Tooling and Equipment 
Part Number  Description 
2M-0849  Washers 
386-3364  Straight Edge Ruler 
473-8690  Outside Electronic Micrometer Set
0-4 inch 
473-8691  Outside Electronic Micrometer Set
2-6 inch 

Replacement Parts

Consult the applicable Parts Identification manual for your engine.

Measurement Requirements


NOTICE

Precise measurements shall be made when the component and measurement equipment are at 20° (68° F). Measurements shall be made after both the component and measurement equipment have had sufficient time to soak at 20° (68° F). This will ensure that both the surface and core of the material is at the same temperature.


Nomenclature



Illustration 3g01573371
(A) Overall thickness of the fan drive bracket
(1) Mounting Surface of the Bracket
(2) Surface of the Bolt Hole Boss


Illustration 4g01579091
(2) Surface of the Bolt Hole Boss


Illustration 5g01581194
(B) Thickness of the front housing
(3) Mounting Surface of the Front Housing
(4) Front Mounting Pads

General Recommendations

Fan Drive Bracket

Do not reuse the bracket if any of the following conditions exist:

  • The thickness of the fan adapter is less than 149.5 mm (5.9 inch). The thickness of the fan adapter is measured from the mounting surface to the surface of the bolt hole boss.

  • The flatness of the mounting surface is greater than 0.25 mm (0.010 inch).

Note: If the 251-7646 Fan Drive Bracket Assembly is reused, the 5P-8245 Washers should be replaced with the 2M-0849 Washers.

Preparation of the Fan Drive Bracket

The mounting surfaces of the fan drive bracket should be clean. Fretting and corrosion should not be present. If cleanup is required, the specifications for flatness and thickness must be maintained. The overall thickness of the fan drive bracket should be reduced to 150.0 ± 0.5 mm (5.91 ± 0.02 inch). The overall thickness should not be less than 149.5 mm (5.89 inch). The tolerance of the profile between the bracket mounting surface and the bolt hole boss surfaces should be within the ± 0.5 mm (0.02 inch) tolerance. The surface finish should maintain a roughness average of 3.2 µm (125 µinch) for all mounting surfaces.

Front Housing

Do not reuse the bracket if any of the following conditions exist:

  • The thickness of the front housing is less than 137.75 mm (5.423 inch).

Preparation of the Front Housing

The mounting surfaces of the front housing should be clean. Fretting or corrosion should not be present. The specifications for flatness and thickness must be maintained if cleanup is required. The overall thickness of the front housing should be maintained at 138.00 ± 0.25 mm (5.433 ± 0.010 inch). The profile tolerance between the mounting surface of the front housing and the front mounting pads should be within the ± 0.25 mm (0.010 inch) tolerance. The surface finish should maintain a roughness average of 3.2 µm (125 µinch) for all mounting surfaces.

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