Paccar Kenworth T800 2012, Manual

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08/12
Section 7
Frame Modifications
WELDING
Kenworth DOES NOT recommend frame welding. The high heat of welding nullifies the special heat treatment of the
rails, greatly reducing the tensile strength of the frame rail. If a frame member becomes cracked from overloading, fatigue,
surface damage or a collision, the only permanent repair is to replace the damaged frame member with a new part.
The following information is provided (for temporary emergency repair). Prior to welding a cracked frame rail, the area
should be beveled (V’d out) to allow for a better weld. To prevent spreading of the crack, a 7 to 9 mm (1/4 in. to 3/8 in.) dia.
hole should be drilled at the end of the crack. Widen the crack along its full length by using two hack saw blades together.
When welding steel frames use the shielded arc method. When welding aluminum frames use either the tungsten inert
gas (TIG) or consumable electrode method. Be sure to obtain full weld penetration along the entire length of the crack.
Precautions
Before welding, disconnect the negative terminal battery cable.
Before welding, disconnect the alternator terminals. Failure to do so could result in
damage to the voltage regulator and/or alternator.
To prevent damage to electrical equipment, disconnect battery cables before arc-welding
on a truck, and be sure that the welding ground lead is connected to the frame. Bearings
and other parts will be damaged if current must pass through them in order to complete
the circuit.
Welding Precautions: All Electronic Engines
Before welding on vehicles with electronic engines, the following precautions should be observed.
1. Disconnect all electrical connections to the vehicle batteries.
2. Disconnect all ECM connectors.
3. Do no use the ECM or engine ground stud for the ground of the welding probe.
4. Ensure that the ground connection for the welder is as close to the weld point as possible. This ensures maxi -
mum weld current and minimum risk to damage electrical components on the vehicle.
5. Turn off key.
Bosch ABS and Wabco ABS: Disconnect ECU.
CAUTION:
CAUTION:
CAUTION:
Note: