Thermo King T-1080S, Maintenance Manual

Page: 118 / 191

Engine Maintenance
117
Engine/Electric Motor (Jackshaft)
Belt
The engine/electric motor (jackshaft) belt is a 3V
belt that also drives the engine side evaporator
fan. A static belt tensioner keeps the belt at the
proper tension. Use the following procedure to
replace this belt or adjust the belt tension.
1. If replacing the belt, remove the electric motor
(jackshaft)/compressor belt.
2. Loosen the locknut on the restraining mount
(snubber) until the chain is loose.
3. Loosen the pulley mounting nut enough to
allow the adjusting bracket to slide, but not
enough to allow the pulley to tilt.
4. Turn the adjusting bolt counter-clockwise
until the belt is loose. If not replacing the belt
go to step 7.
5. Remove the old belt and note how it fits on the
pulleys.
6. Install the new belt. Make sure it fits on the
pulleys correctly.
7. Take a straight edge, place it against the side
of the muffler can and mark the frame as
shown below. This is the unloaded engine
position.
Figure 204: Mark Frame
8. Turn the adjusting bolt clockwise to make the
pulley descend and tighten the belt until it is at
approximately 10 Hz lower than the correct
belt tension setting using the frequency gauge
P/N 204-1903 on the top span. This will pull
the engine towards the belt. See
“Specifications” for the correct belt tension
settings.
NOTE: When using the frequency gauge
P/N 204-1903, place the probe near the belt
with the LED shining on the belt. Pluck the
belt with a metal tab as shown below to get an
accurate reading. Take three readings and
average them.
1. Pulley Mounting Nut
2. Pulley
3. Adjusting Bracket
4. Adjusting Bolt
Figure 203: Belt Tensioner Components
3
2
1
4
1. Probe
2. Metal Tab
Figure 205: Using Frequency Gauge P/N 204-1903
1 2