Apply a stripe of tamper proof indicator
paint (Torque Seal) to the screw head.

FIGURE 50: CLUTCH HOLD DOWN BOLT

7. Turn the clutch by hand and pay attention

to grinding noises, the clutch must spin
freely.
Working gap between the clutch and the
coil must be: 0.024 in - 0.035 in 0.60 mm 0.90 mm (figure 51)
During cleaning or other work on the
compressor, the clutch must be covered to
prevent the penetration of greasy liquids,
grease or dirt particles in the working gap.

Writer: mg

FIGURE 51: CLUTCH WORKING GAP

Special Bulletin

SP18-307
Date

Expiration

Release

Page

11.2018

11.2020

1

25(31)

8. Reinstall the two drive belts (crank and

clutch pulleys) (figure 52).

FIGURE 52: COMPRESSOR BELTS REINSTALLATION

9. Reinstall the belt tensioner and put some

tension to the belts (figure 53).
-

Apply medium strength (blue) thread
locker on bolt (B) and hand tighten
snugly.

-

Put tension to the belts using bolt (A).

FIGURE 53: BELT TENSIONNER INSTALLATION

10. Adjust the belt tension to its final value
using a suitable belt tension gauge (figure
54).
-

Adjust tension to value below using bolt
(A).

Proper tension for the belts should read as
follows:
90-100 lbs with new belts
75-85 lbs with used belts
Writer: mg

FIGURE 54: CHECKING BELT TENSION

Special Bulletin

-

When proper tension is achieved, lock
bolt (A) in place with the jam nut and
tighten bolt (B) to 43 lb-ft. (58 N-m).

-

Apply a stripe of tamper proof indicator
paint (Torque Seal) to the bolt heads
(figure 55).

SP18-307
Date

Expiration

Release

Page

11.2018

11.2020

1

26(31)

FIGURE 55: TORQUE SEAL ON INSTALLED AND
ADJUSTED BELT TENSIONER

PART 5
AC COMPRESSOR OIL & REFRIGERANT FILLING

CAUTION
This part of the procedure must only be performed by a certified HVAC Technician.

1. Remove and clean the compressor pan
filter/strainer and the magnetic drain plug
(figure 56).
-

Remove drain plug (use a suitable
container to catch residual oil).

-

Pull out filter/strainer.

-

Clean with suitable degreaser.

-

Replace gasket with part # 950544
included

-

Reinstall filter/strainer and drain plug.

Do not put sealant on the drain plug thread.

FIGURE 56: FILTER/STRAINER AND THE MAGNETIC DRAIN
PLUG LOCATION

TORQUE: 37 to 52 lb-ft (50 to 71 Nm)

Writer: mg

Special Bulletin

SP18-307
Date

Expiration

Release

Page

11.2018

11.2020

1

27(31)

2. Fill the compressor with fresh compressor
oil.
-

Fill a compressor oil pump with the
same oil quantity that was previously
removed.

FIGURE 57: OIL PUMP CONNECTION (BACK OF THE
COMPRESSOR)

Bitzer A/C compressor – oil specification:
Oil type : Polyester ISO68 for R134a
Recommended : Bitzer BSE55 (POE)

-

Connect the pump to the pressure port
at the back of the compressor (figure
57).

-

Pump the oil in the compressor up to
the full level. The driver side sight glass
must be filled to the top and the curb
side sight glass up to the max level
mark (figure 58 & figure 59).

-

When the normal oil level is reached,
add 10oz (300 ml) of extra oil to the
compressor as per new Prevost
requirement.

FIGURE 58: DRIVER SIDE OIL LEVEL BEFORE 10oz ADDON

FIGURE 59: DRIVER SIDE OIL LEVEL (BEFORE 10oz ADDON

Writer: mg

Special Bulletin

SP18-307
Date

Expiration

Release

Page

11.2018

11.2020

1

28(31)

3. Reconnect the AC gauges to the high and
low pressure service ports of the
compressor.
-

Red hose to the red high pressure
service port (figure 60)

-

Blue hose to the blue low pressure
service port (figure 61).
Make sure both valves are closed
FIGURE 60: CONNECTED HIGH-PRESSURE SIDE

FIGURE 61: CONNECTED LOW-PRESSURE SIDE

4. Connect the recovery station to the gauges
and vacuum the compressor 30psi below
atmospheric pressure.
-

Connect the yellow hose coming from
the gauges to the inlet of the recovery
station.

-

Start the recovery station.

-

When vacuum reaches the correct
value, close the gauge valves to
maintain vacuum and stop the recovery
station (figure 62).

Writer: mg

FIGURE 62: 30PSI VACUUM READING

Special Bulletin

SP18-307
Date

Expiration

Release

Page

11.2018

11.2020

1

29(31)

5. Connect the recovery station to the fill tank
and add refrigerant to the compressor
(figure 63).
-

Connect the yellow hose coming from
the gauges to the outlet of the recovery
station.

-

Connect the inlet of the recovery
station to the tank.

-

Put the fill tank on the scale

-

Start the recovery station and add the
same amount of R134A refrigerant that
was previously removed (the weight of
the tank should reach its initial value)
(figure 64).

FIGURE 63: RECOVERY STATION CONNECTION

FIGURE 64: FILL TANK CONNECTION

6. With the compressor filled, disconnect the
hoses from the compressor ports.
Close all valves on gauges, recovery
station and tank.
-

Put back the red and blue protective
caps on the service ports (the red high
pressure cap in front the blue cap at
the rear of the compressor) (figure 65)

Writer: mg

FIGURE 65: PROTECTIVE CAPS ON HIGH & LOW SERVICE
PORTS

Special Bulletin

SP18-307
Date

Expiration

Release

Page

11.2018

11.2020

1

30(31)

7. Back seat both compressor high and low
pressure service valves to reconnect the
compressor to the system (figure 66).
-

With a square service valve wrench,
back seat both valves (screw out).

Do not over torque the valves (12 lb-ft (16
Nm) max).
-

Put back the black protective cap on
both the high and low shutoff valves.
FIGURE 66: BACK SEATED SHUTOFF VALVE

8. Start the vehicle and check for proper
operation of the HVAC system (figure 67).

FIGURE 67: RUNNING HVAC SYSTEM

PARTS / WASTE DISPOSAL
Return replaced parts to Prevost with A.F.A. for full reimbursement.
Discard waste according to applicable environmental regulations (Municipal/State[Prov.]/ Federal)

Writer: mg

Special Bulletin

SP18-307
Date

Expiration

Release

Page

11.2018

11.2020

1

31(31)

ESTIMATED TIME
The time required to perform this special bulletin is approximately 3.5 hours.

OTHER
VBC Bulletin

N/A

Fail Code

22.05

Defect Code

09

Syst. Cond

B

Causal Part

950002

Access all our Service Bulletins on

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or scan the QR-Code with your smart phone.

Prevost engages in a continuous program of testing and evaluating to provide the best possible product. Prevost, however, is not
committed to, or liable for updating existing products.

Writer: mg