42-69

Excessive Moisture in the Air System
FLA COE
FLB COE
FLD Conventional
Business Class
FLC 112 Conventional

Century Class Conventional
Argosy COE
Cargo
Columbia

Freightliner
Service Bulletin

Coronado
Business Class M2
> Cascadia
108SD/114SD

Description of Revisions: This bulletin replaces the version dated
April 2013. The title is changed and a reference to transmission
solenoid failure has been added.

General Information
Some EPA10 vehicles with HDEP engines and WABCO or Bendix air dryers are experiencing excessive moisture in the air system, possibly resulting in a transmission solenoid failure, or a DEF system fault code (see
Table 1) and/or a clogged air inlet screen (DDE A0001400594) in the DEF metering unit. If a vehicle is showing
this symptom, perform the inspection below to determine the cause of the excess moisture, and make repairs
as needed.

SPN
3361
4335

FMI
7
7

DEF System Fault Codes
Description
DEF Unit Unable To Clear Restriction
DEF Air Pressure Low

Table 1, DEF System Fault Codes

Inspection
Verify that the air tanks are being drained daily as directed in the Cascadia Driver’s Manual.
Check the vehicle for air system components that were installed after the vehicle was spec’ed and
manufactured. Such components may require air volumes in excess of the air dryer’s rating, possibly resulting
in excessive compressor cycling and moisture in the air system.
If the above criteria are satisfactory, perform all of the checks in Table 2 to eliminate issues that may cause excessive moisture in the air system.
Air System Troubleshooting
Why

Check
Check the air system
plumbing for leaks.

Results

Air leaks cause extended compressor run times
Leaks found.
resulting in increased air volume and
temperature to the dryer making it difficult for the
dryer to remove water from the air.
No leaks.

Debris or leakage
Check the dryer purge
Consequences are similar to a plumbing air leak. found.
valve for debris or
Rubber or weld slag particles may be found.
leakage.
No debris or leakage.
A restriction between the governor and air dryer
will block the purge signal to the dryer, causing
build-up of water, resulting in water in the air
Kink found.
system.
Check the governor air
A restriction between the governor and air
lines for kinks.
compressor will cause the compressor to
continually pump, overloading the dryer with hot
No kinks found.
water-saturated air, resulting in water in the air
system.

Freightliner Service Bulletin, June 2013

What To Do
Repair any leaks as
needed.
Go to the next check.
Go to the next check.
Clean or replace the
purge valve.
Go to the next check.
Go to the next check.
Replace any kinked air
line.
Go to the next check.

Go to the next check.

Page 1

42-69

Excessive Moisture in the Air System

Freightliner
Service Bulletin

Check

FLA COE
FLB COE
FLD Conventional
Business Class
FLC 112 Conventional

Century Class Conventional
Argosy COE
Cargo
Columbia

Air System Troubleshooting
Why
Park the vehicle on a level surface and chock
the tires.
Build up system air pressure, then shut off the
engine.

Coronado
Business Class M2
> Cascadia
108SD/114SD

Results

Leak found.

What To Do

Repair or replace the
park brake chamber.

Release the park brake.
Check for a leaking
spring brake chamber
internal seal on the
truck or trailer.

With the park brake released, feel for air leaking
out of the bottom of the rear service brake relay
valve exhaust port.
If air is leaking from the exhaust port of the
service relay valve, then air that is holding back
the spring brakes (park brake chamber) is
leaking over to the service side of the brake
No leaks.
chamber (usually because of a bad diaphragm)
and through the service air lines and out the
open exhaust port of the service brake relay
valve. This air leakage will result in excessive air
compressor run time.

No further inspection is
needed. Consider
installing an in-line air
cooler.

Table 2, Air System Troubleshooting

If the issue persists, the air dryer inlet air temperature may be excessive, resulting in reduced dryer
performance. Install an in-line air cooler loop, or a longer air line, depending on the vehicle configuration.
If the dryer is mounted on the left hand frame rail, follow the procedure in "Air Cooler Loop Installation, LeftHand Forward Frame-Mounted Dryer" below.

Air Cooler Loop Installation, Left-Hand Forward Frame-Mounted
Dryer
Refer to Fig. 1 for this procedure.
1. Park the vehicle on a level surface, shut down the engine, and set the parking brakes. Chock the wheels
securely.
2. Disconnect the batteries at the negative post.
3. Drain the air from the air system.
4. Remove the grille. See Section 88.00, Subject 110 of the Cascadia Workshop Manual.
5. Open the hood.
6. Remove the bumper. See Group 31 of the Cascadia Workshop Manual.
7. Relocate the air temperature sensor on the right side of the frame closing crossmember down one hole.
8. Remove the rock screen from the lower face of the radiator.
9. Install the cooler-loop mounting brackets. See Fig. 1.
10. Position the P-clamps on the cooler loop and install the cooler loop on the brackets. Do not tighten the
P-clamp fasteners at this time. See Fig. 1.

Page 2

Freightliner Service Bulletin, June 2013

42-69

Excessive Moisture in the Air System
FLA COE
FLB COE
FLD Conventional
Business Class
FLC 112 Conventional

Century Class Conventional
Argosy COE
Cargo
Columbia

Coronado
Business Class M2
> Cascadia
108SD/114SD

Freightliner
Service Bulletin

1

10
11
12

13
6
2

5
5
4

3

8
9

7

8

11/07/2012

1.
2.
3.
4.
5.
6.
7.

Cooler Loop
P-Clamp
Mounting Bracket
Nut
Washer
Bolt
Nut

f422567

8. Washer
9. Bolt
10. Hood Cylinder
11. Braided Hose, Cooler-to-Compressor Discharge Line
12. Dryer
13. Braided Hose, Cooler-to-Dryer
Fig. 1, Cooler Loop Installation (AD-9/AD-IP dryer shown)

11. Cut any zip ties as needed, and move the insulation to access the braided compressor-discharge line between the frame rail fitting and the dryer. Remove the line and discard the line and insulation.
12. Install the new braided line from the loop to the frame rail connection. See Fig. 2 for AD-9/AD-IP Dryers, or
Fig. 3 for Wabco 1200 Plus Dryer.
13. Install the new braided line from the loop to the dryer. See Fig. 2.

Freightliner Service Bulletin, June 2013

Page 3

42-69

Excessive Moisture in the Air System

Freightliner
Service Bulletin

1

FLA COE
FLB COE
FLD Conventional
Business Class
FLC 112 Conventional

2

Century Class Conventional
Argosy COE
Cargo
Columbia

Coronado
Business Class M2
> Cascadia
108SD/114SD

3
4
3
1

5

4

1

1
11/07/2012

2

f422568

1. Cooler Loop
2. Braided Hose, Cooler-to-Compressor Discharge
Line
3. Dryer
4. Compressor Discharge Line
5. Braided Hose, Cooler-to-Dryer
Fig. 2, Braided Line Installation, AD-9/AD-IP Dryers

5
11/08/2012

f422570

1. Cooler Loop
2. Braided Hose, Cooler-to-Dryer
3. Braided Hose, Cooler-to-Compressor Discharge
Line
4. Compressor Discharge Line
5. Dryer
Fig. 3, Braided Line Installation, Wabco 1200 Plus
Dryer

14. On vehicles with AD-9/AD-IP dryers only, disconnect the left side hood cylinder end at the frame rail mounting bracket, and remove the attaching bolt. Place a P-clamp over the braided line between the loop and the
dryer, then, using the same bolt, install the clamp on the inside of the hood cylinder mounting bracket. See
Fig. 4. Install the hood cylinder.
15. Secure any loose wires or hoses around the dryer with zip ties as needed.
16. Tighten the cooling loop mounting fasteners. See Fig. 1.
17. Charge the air system and check the installation for leaks. Repair as needed.
18. Install the rock screen.
19. Install the bumper. See Group 31 of the Cascadia Workshop Manual.
20. Close the hood.
21. Install the grille. See Section 88.00, Subject 110 of the Cascadia Workshop Manual.

Page 4

Freightliner Service Bulletin, June 2013

42-69

Excessive Moisture in the Air System
FLA COE
FLB COE
FLD Conventional
Business Class
FLC 112 Conventional

Century Class Conventional
Argosy COE
Cargo
Columbia

Freightliner
Service Bulletin

Coronado
Business Class M2
> Cascadia
108SD/114SD

2

1

3
4
5

11/07/2012

f422569

1. Bolt
2. P-Clamp

3. Nut
4. Hood Cylinder

5. Nut

Fig. 4, P-Clamp Installation (AD-9/AD-IP dryers only)

Parts
Parts are available thorough the PDC. Refer to Table 3 for required parts for BENDIX AD-IP/AD-9 installations,
Table 4 for required parts for WABCO SS1200 Plus installations.

Part
A12-25748-000
A12-25763-019
A12-25763-022
12-25747-000
UMP S630G10
23-09432-075
23-13861-104
23-10900-125
23-09114-003
23-13861-108
23-09440-150
23-09528-047
23-11357-012

Required Parts, BENDIX AD-IP/AD-9 Installations
Description
TUBE-ASSY,DISCH,IN-RAIL,LHFF
HOSE ASSY-WIREBRAID,#10,HITEMP
HOSE ASSY-WIREBRAID,#10,HITEMP
BRKT-ENG RTG,LH,ISC/L,’10
CLAMP-SUPPORT,.625 ID
1/4-20x3/4 HCS GR8 PH,Oil
1/4-20 ALL MTL PREV TORQUE HEX FLNG L/N GR F or G7
0.281X0.625X0.065 SPCL FLT WSHR SST PSVT BLK OXD
1/2 HRDND FLT WSHR F436 TYP 1 ZN,CL
1/2-13 ALL MTL PREV TORQUE HEX FLNG L/N FR F ZN/A
1/2-13X1-1/2 HCS GR8 PH,OIL
7/8X5/8 SINGLE LOOP CSMND CLAMP STL/NEOPRN
3/4x5/8 SINGLE LOOP CUSH HOSE CLMP STL/NEOPRN ZN U

Quantity
1
1
1
2
4
4
4
8
8
4
4
4
1

Table 3, Required Parts, BENDIX AD-IP/AD-9 Installations

Part
A12-25748-000

Required Parts, WABCO SS1200 Plus Installations
Description
TUBE-ASSY,DISCH,IN-RAIL,LHFF

Freightliner Service Bulletin, June 2013

Quantity
1

Page 5

42-69

Excessive Moisture in the Air System

Freightliner
Service Bulletin

Part
A12-25763-019
A12-23236-015
12-25747-000
UMP S630G10
23-09432-075
23-13861-104
23-10900-125
23-09114-003
23-13861-108
23-09440-150
23-09528-047
23-11357-012

FLA COE
FLB COE
FLD Conventional
Business Class
FLC 112 Conventional

Century Class Conventional
Argosy COE
Cargo
Columbia

Coronado
Business Class M2
> Cascadia
108SD/114SD

Required Parts, WABCO SS1200 Plus Installations
Description
HOSE ASSY-WIREBRAID,#10,HITEMP
HOSE ASSY-WIREBRAID,#10,HITEMP
BRKT-ENG RTG,LH,ISC/L,’10
CLAMP-SUPPORT,.625 ID
1/4-20x3/4 HCS GR8 PH,Oil
1/4-20 ALL MTL PREV TORQUE HEX FLNG L/N GR F or G7
0.281X0.625X0.065 SPCL FLT WSHR SST PSVT BLK OXD
1/2 HRDND FLT WSHR F436 TYP 1 ZN,CL
1/2-13 ALL MTL PREV TORQUE HEX FLNG L/N FR F ZN/A
1/2-13X1-1/2 HCS GR8 PH,OIL
7/8X5/8 SINGLE LOOP CSMND CLAMP STL/NEOPRN
3/4x5/8 SINGLE LOOP CUSH HOSE CLMP STL/NEOPRN ZN U

Quantity
1
1
2
4
4
4
8
8
4
4
4
1

Table 4, Required Parts, WABCO SS1200 Plus Installations

Warranty
This procedure is warrantable only if the described condition exists and the repair is performed within the applicable base or extended coverage warranty period. If a failure is not found, this procedure is considered preventive and warranty does not apply.
Normal warranty applies. See Table 5 for QuickClaim damage code and labor allowance information. Refer to
this service bulletin by number at the beginning of the claim comments. See Table 6 for OWL VMRS codes and
labor allowance information. Enter this service bulletin number in the Service Bulletin # field.

Damage Code
107-001335940

SRT Code
107-5010A

QuickClaim Damage Code and Labor Allowance
Description
Add Discharge Cooling Loop, Install

Time: Hours
1.2

Table 5, QuickClaim Damage Code and Labor Allowance

Primary Failed Part
A12-23236-018

OWL VMRS Codes and Labor Allowance
Component
Cause Code SRT Code
Description
Code
013-009-023
27
107-5010A Add Discharge Cooling Loop, Install

Time: Hours
1.2

Table 6, OWL VMRS Codes and Labor Allowance

Page 6

Freightliner Service Bulletin, June 2013