OPTION AR-GUARD 3772754 - Caterpillar

Introduction
This Special Instruction outlines the rework procedure for the engine muffler bracket on certain 306E, 307E, and 308E Mini Hydraulic Excavators. Do not perform any procedure that is outlined until you have read the information in this publication. Do not order and parts until you understand the information that is contained in this publication.Recommended Parts
Table 1
Parts for Muffler Replacement    
Qty     Part Number     Part Name     Machines    
1     389-8796     Muffler As     306E & 307E    
1     390-2320     Muffler Cover     306E & 307E    
8     8T-4136     Bolt     306E & 307E    
4     7X-7729     Washer     306E & 307E    
8     7X-7729     Washer     308E    
1     431-0570     Muffler Cover     308E    
1     457-0233     Muffler As     308E    
8     8T-4196     Bolt     308E    
4     8T-4121     Hard Washer     306E & 307E    Inspection Procedure
Park machine on level ground with the implements lowered.Ensure that the engine and muffler are cooled down sufficiently before inspection.
Illustration 1 g03738513
Inspect the muffler intake pipe for any weld cracks at the joint.
Replace the muffler if the welded joint has completely cracked.Rework the cracked weld if the welded joint is not completely cracked.Rework Procedure
Welding Procedure
Illustration 2 g03738611
(A) AWS A5.18 ER70S-2 or equivalent
Reweld the intake pipe to the muffler body.ReferenceSpecial Instruction, REHS1841, "General Welding Procedures"Mounting Bracket Rework Procedure
Illustration 3 g03738699
(1) Mounting bracket (left) (2) Mounting bracket (right)
Ensure left mounting bracket (1) is tightened to support the muffler.Bolt torque ... 55 10 N m (40 7 lb ft)
Remove right mounting bracket (2) .
Illustration 4 g03693924
Remove the paint from bolt holes (3) and surface (4) .
Reinstall right mounting bracket (2). Install the washers and bolts. Do not tighten the bolts to the final torque.
Remove left mounting bracket (1) .
Remove the paint from bolt holes (3) and surface (4) .
Reinstall left mounting bracket (1). Install the washers and bolts. Do not tighten the bolts to the final torque.
Ensure that the mounting brackets do not have any clearance or gaps between the mounting surfaces and the brackets.Evenly tighten all the bolts to 55 10 N m (40 7 lb ft).
Start the engine and observe for any abnormal vibration on the muffler brackets.