Engine
07
Belt Replacement Tips
1. Never replace just one belt on a two groove single pulley set up. Never install only one belt from
a matched set: always install the complete set.
2. Always check the condition of the pulleys before replacing belts. Inspect the pulleys for chips,
cracks, bent sidewalls, rust, corrosion, or other wear factors. Replace any pulleys found to be
damaged or defective.
3. Misaligned pulleys result in shortened belt life.
4. Check the alignment between pulleys as follows:
a. Position a straight edge or cord line to touch both pulleys at all points. The shafts must be
parallel.
b. Rotate each pulley a half revolution and note whether the contact of either pulley with the
straight edge or cord line is disturbed. If so, this indicates a bent shaft or warped pulley.
5. Move the belt tension adjustment to the position where it provides the most slack. In some cases
it maybe necessary to remove the accessory to install the belt.
6. Place belts in the pulley grooves by hand.
To carry their full loads, belts must grip the entire area of contact with the pulley. When operated too
loosely belts can slip, heat, burn, grab, or snap. Many more belts fail from under tightening than from
over tightening. When operated too tightly, belts can damage the engine by causing side loading on the
crankshaft, crankshaft bearings, and accessory bearings. Excess tension also stretches and weakens belts.
Never pry or force a belt onto the pulley with a screwdriver, crowbar,
wedge, etc. Both belt and drive may be damaged by such abuse.Belt
replacement Procedures
Keep fingers clear of drive belts when the engine is operating. Before
adjusting belt tension or installing a new belt, attach a “Do Not Operate”
tag to the engine start switches and controls in the driver’s area. Place
the engine power switch on the Rear Run Box in the “ENGINE OFF”
position.
Alternator and Water Pump Drive Belts
The belt tensioner on the engine automatically maintains the proper tension. Belt tension cannot be ad-
justed. The belt tensioner is designed to operate within the limit of arm movement provided by the cast
stops when the belt length and geometry are correct. If the tensioner is hitting either of the limits during
operation, check the mounting brackets and the belt length. Loose brackets, bracket failure, alternator
movement, incorrect belt length or belt failure can cause the tensioner to hit the limits.
Summary of Contents for LOW FLOOR
Page 18: ...Specifications 18...
Page 58: ...Preventive Maintenance 58...
Page 110: ...Engine 110...
Page 138: ...Transmission Driveline Rear Axle 138...
Page 182: ...Suspension 182...
Page 260: ...Air System 260...
Page 420: ...Electrical System 420 Deutsch DT Series Connectors...
Page 421: ...Electrical System 421...
Page 422: ...Electrical System 422 Deutsch HD 10 Series Connectors...
Page 423: ...Electrical System 423...
Page 424: ...Electrical System 424 Deutsch HD 30 Series Connectors...
Page 425: ...Electrical System 425...
Page 442: ...Heating Air Conditioning 442...
Page 492: ...Body and Interior 492 Figure 11 33 USSC Seat Assembly...
Page 493: ...Body and Interior 493 Figure 11 34 USSC Seat Suspension Assembly...
Page 495: ...Body and Interior 495 Figure 11 37 Seat Air Connections...