Removal Of Broken Head Bolts On 3176 Engines Without Removing The Aluminum Spacer Deck{1100} Caterpillar

Removal Of Broken Head Bolts On 3176 Engines Without Removing The Aluminum Spacer Deck{1100}

Usage:

3176 2YG

Engines:: 3176 (S/N: 2YG; 7LG; 5XN); 3176B (S/N: 9CK; 9WK; 3NL)
Challenger Tractor:: 75 (PIN: 4CJ); 75C (PIN: 4KK); 85 (PIN: 9TK)

Introduction

This Special Instruction provides a method for removing broken cylinder head bolts from the cylinder block on 3176 Engines without removing the aluminum spacer deck. The method involves welding the broken bolt to a hollow pipe that is installed in the bolt hole of the spacer deck. By eliminating the need to remove the spacer deck, the repair can be made quicker at a lower cost to the customer.

Required Parts

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Table 1
Quantity	Part Number	Description
1	3B-7743	3/8 inch X 6 inch Pipe Nipple ⁽¹⁾
15	4C-9667	E7018 Electrode ⁽²⁾
15	9U-6656	Stud Plus Electrode
1	2J-3506	3/4 -10 Hex Nut

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^( 1 )	A hollow tube that is 150 mm (6 inch) long with an outside diameter of approximately 12 mm (0.5 inch) may also be used.
^( 2 )	Any electrode that is similar to the E7018 electrode can be used. Refer to the Tools And Shop Products Guide, NENG2500, "Section 10".

Required Tools

Pedestal Grinder
Electric Arc Welder
Narrow Chisel
Narrow Vacuum Or Compressed Air Nozzle
Pipe Wrench
Locking Pliers
Clamps Or Wide Jaw Locking Pliers

Procedure

Preparing The Pipe

Grind a profile that matches the profile of the broken bolt on the end of the pipe nipple. Matching the profile will reduce any gap between the pipe and the broken bolt during the welding process.

Grind the outside diameter of the pipe in order to fit the pipe down the bolt hole in the aluminum spacer deck. The pipe should be able to contact the top of the broken bolt when the pipe is installed in the hole.

Installing The Pipe

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Illustration 1	g00467782
(1) Pipe. (2) Aluminum Spacer Deck. (3) Cylinder Block

Install the pipe (1) into the hole. Ensure that the pipe is against the broken bolt and that the profiles line up.

Secure a pair of locking pliers to the pipe so that the pipe can be held down on the bolt while you are welding.
If you are using clamps or wide jaw locking pliers, secure the locking pliers that are holding the pipe to the engine so that the pipe remains securely on the bolt during the welding process.

Disconnecting The Electrical System

Disconnect the battery ground from the vehicle's electrical system. As an added precaution, the ECM J1 connector and J2 connector can be removed in order to prevent damage to the engine electronics.

Grounding The Welder

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Illustration 2	g00467828

Ground the electric arc welder to the engine cylinder block at a location (4) close to the broken bolt. Make sure that the ground is secure. The ground should provide a good electrical contact with the engine. Do NOT ground the welder to any electrical system grounds.

Welding A Column On The Bolt

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Illustration 3	g00467832

Use the Stud Plus 9U-6656 Electrode (5) and an electric arc welder in order to begin welding on the center of the bolt. The recommended amperage for this size is 80 A to 120 A. Refer to the Tools And Shop Products Guide, NENG2500, "Section 10" for additional information on the Stud Plus electrode. Build up a column of welded material (6) in the center of the hollow pipe. Keep the electrode in the center of the pipe in order to allow the flux to flow to the outside. The flux that is surrounding the column will prevent welding the bolt to the cylinder block. The flux also prevents damage to the aluminum spacer deck. Continue to weld the column until the electrode is submerged in the flux. When the electrode is submerged, stop welding. Allow the metal and the flux to harden.

Removing The Flux

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Illustration 4	g00468055

Use a narrow chisel in order to remove the top layer of flux (7). Remove the chips of flux with a vacuum or a compressed air nozzle. Always use proper eye protection.

Continue to build the welded column in 4 to 6 mm (0.20 to 0.25 inch) increments. Remove the flux after each increment. Continue until the welded column is 15 to 20 mm (0.6 to 0.8 inch) in length. Clean the flux off the final layer of the welded material.

Welding The Column To The Pipe

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Illustration 5	g00468056

Weld the column to the inside of the pipe with an E7018 electrode. Weld around the entire inside of the pipe in a complete circle in order to ensure that the pipe and the column are securely connected. Be careful not to apply too much heat at one time which could cause a hole to burn through the pipe and damage the aluminum spacer deck. Continue to weld until the weld connects 8 to 12 mm (0.40 to 0.50 inch) of the pipe.

Welding A Nut To The Pipe

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Illustration 6	g00468061

Place the nut (8) over the top of the pipe. Support the nut with locking pliers. Weld the nut to the pipe on the top face of the nut with an E7018 electrode.