C 2500 Truck 2WD V8-5.7L VIN R (1997)
Evaporative Fuel Vapor Return Hose: Service and Repair
EVAP Pipe Repair
Repair the EVAP pipe in sections using brazed seamless steel tubing meeting GM specification 123M or equivalent or hose identified with the word
Fluoroelastomer. Hose not so marked could cause failure or failure to meet emission standard.
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Do not use copper or aluminum tubing to replace steel tubing. Those materials do not have satisfactory durability to withstand normal vehicle
vibrations.
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Do not use rubber hose within 100 mm (4 inches) of any part of the exhaust system or within 250 mm (10 inches) of the catalytic converter.
The replacement hose's inside diameter must match the steel tubing outside diameter.
1. In repairable areas, cut a piece of fuel hose 100 mm (4 inches) longer than the portion of the line being removed. When more than a 150 mm (6
inches) length of pipe is removed, use a combination of steel tubing and hose so that the entire hose length will not be more than 250 mm (10
inches).
2. Cut the ends of the pipe remaining on the vehicle square by using a tubing cutter. By using the first step of a double flaring tool, form a bead on
the ends of both pipe sections. If the pipe is too corroded to withstand bead operation without damage, the pipe should be replaced. If a new
section of pipe is used, form a bead on both ends.
3. Use screw type hose clamps GM part number 2494772 or equivalent. Slide the clamps onto the pipe and push the hose 50 mm (2 inches) onto each
portion of the fuel pipe. Tighten the clamps on each side of the repair.
