SFN-20240109D Replace cab bar

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TICO Document #: SFN-20240109D (formerly TES 154)

Compliance: Cab protection bar may develop cracks where the frame mounting plate joins the vertical tube.

Description of Procedure: Replace cab bar. The following is a temporary fix until cause can be determined

Units Affected: Units with galvanized cab bars.

Parts Required: P/N: SK 0000 (QTY 3)

Diamond shape, 10mm plate, 50mm x 100mm (see weld procedure below)

Planned Labor: N/A

Instructions:

  1. Park the vehicle on a flat surface, apply the parking brake and chock wheels. If your company utilizes a “Lock Out, Tag Out” policy, you should employ it during this procedure.

  2. Remove the battery box cover and disconnect the battery cables. Remove batteries or insulate terminal ends with a non-conductive wrap to prevent inadvertent contact between battery terminals and cables.

  1. Use a welding blanket to cover the rear of the cab, grating underneath the cab protection bar, tractor protection valve, fuel components, and exhaust components to prevent the weld by-product from damaging these components during the repair process.

  1. Locate a vertical post to the immediate right of the cab door.

  1. Position the lap plate over the crack in the post. Mark the outline on three sides of the post. The lap plate should be a diamond-shaped 100 mm by 50mm by 10mm thickness, mild steel, recommend ASTM A36.

  2. Remove the finish to 10mm away from the scribed line. Do not remove the finish inside the scribed line.

  3. Remove the finish for 10mm on both sides of the crack. Grind crack into “V” shape groove.

  1. Remove the airlines from fittings, and harness from trailer plug connection box.

  2. Pull the cab bar electrical harness and airline tubing up towards the top of the cab bar above the area to be welded to prevent damage from welding heat during the repair process.

  3. Align the upper tube with the lower tube using clamps.

Weld Procedure:

  1. Position upper tube over the lower tube, and clamp in place.

  2. Apply sufficient tack weld to secure in place.

  3. Deposit 10mm weld all the way around post post-filling prepared groove. Grind post weld flat where lap plates will be installed, then place lap plates over crack on forward, frame side, and outside (not where the handle attaches) and deposit 10mm fillet weld all around.

Note: Weld settings are for FCAW process using Lincoln Electric UltraCore 71A85 wire, and 85% Argon/15% CO2 gas mixture or equivalent.

  1. Paint the gusset with rust-inhibitive paint and primer.

  1. Reinsert airlines and connect electrical harnesses.

  1. Reconnect battery terminals.

  1. Remove “Lock Out, Tag Out” plaque.

  1. Return vehicle to service.