121 Maintenance Section (D6T LGP (OEM)) Maintenance Support
WEBM1000
Maintenance Support
Severe Service Application
Welding on Machines and Engines with Electronic Controls
An engine which operates outside of normal conditions is operating in a severe service application.
Do not weld on any protective structure. If it is necessary to repair a protective structure, contact your Caterpillar dealer. Proper welding procedures are necessary in order to avoid damage to the electronic controls and to the bearings. When possible, remove the component that must be welded from the machine or the engine and then weld the component. If you must weld near an electronic control on the machine or the engine, temporarily remove the electronic control in order to prevent heat related damage. The following steps should be followed in order to weld on a machine or an engine with electronic controls. 1. Turn off the engine. Place the engine start switch in the OFF position. 2. If equipped, turn the battery disconnect switch to the OFF position. If there is no battery disconnect switch, remove the negative battery cable at the battery. NOTICE Do NOT use electrical components (ECM or sensors) or electronic component grounding points for grounding the welder. 3. Clamp the ground cable from the welder to the component that will be welded. Place the clamp as close as possible to the weld. Make sure that the electrical path from the ground cable to the component does not go through any bearing. Use this procedure in order to reduce the possibility of damage to the following components: • Bearings of the drive train
An engine that operates in a severe service application may need more frequent maintenance intervals in order to maximize the following conditions: • Reliability • Service life The number of individual applications cause the impossibility of identifying all of the factors which may contribute to severe service operation. Consult your Caterpillar dealer for the unique maintenance that may be necessary for your engine. An application is a severe service application if any of the following conditions apply:
Severe Environmental Factors • Frequent operation in dirty air • Frequent operation at an altitude which is above 1525 m (5000 ft) • Frequent operation in ambient temperatures which are above 32 C (90 F) • Frequent operation in ambient temperatures which are below 0 C (32 F)
Severe Operating Conditions • Frequent operation with inlet air which has a corrosive content • Operation with inlet air which has a combustible content
• Hydraulic components
• Operation which is outside of the intended application
• Electrical components
• Operation with a plugged fuel filter
• Other components of the machine
• Extended operation at low idle (more than 20% of hours)
4. Protect any wiring harnesses and components from the debris and the spatter which is created from welding.
• Frequent cold starts at temperatures below 0 C (32 F)
5. Use standard welding procedures in order to weld the materials together.
• Frequent dry starts (starting after more than 72 hours of shutdown)
