SB-10044331-4870

LACMTA: Air Compressor Suction Line Rework

Prepared by:

Kalman Takacs
Field Service Engineer
256-241-1243

Approved By:

James Shropshire
Field Service West Regional Manager

Property and Top Bus Number: LA 45CLFW, 218000, 269000

Issue:

The air compressor is pumping oil into the air system.

06-12-2012
Reason/ cause:

The air compressor on the earlier Metro 45 CLFW fleet is naturally aspirated.
During Q1 2010, Cummins and WABCO recommended modifying LA Metro bus
fleet from naturally aspirated air to boosted air from the engine turbocharger for
the purpose of improving the air compressor durability.
With the naturally aspirated air plumbing, the duty cycle and air compressor head
temperatures on the 45CLFW fleet were found to be relatively high in certain
operating conditions. Secondary, the lack of pressure above the pistons during
the suction cycle lets oil pass through the piston rings. With this condition, oil
may enter into to the air system.

Solution:

This work instruction will convert the engine mounted air compressor to turbocharged (boosted) air supply to reduce the duty cycle of the air compressor and
help prevent the passage of oil into the air system.

Work instruction number: L3/FSV-098
L4/QUA-003

Revision: Initial

Date: 05/22/2012
Revision: Initial
1/8

LACMTA: Air Compressor Suction Line Rework

Number of affected buses:

301

Estimate repair hours/bus:

3 hours

Necessary parts:
Hump Hose, 4”IDx6”, silicone,

Part #: 416.06.1530.912,

1 / bus,

Clamps, constant torque, 4” ID,
Plug, 1”,
Hose, silicone, 1”ID, 4-ply, 144”L,
Turbo Protection Valve Kit,
Thread sealer,

Part #: 416.06-1530-916,
Part #: 10A-1355-007,
Part #: 605-1375-013,
Graham White: CKX5
Part #: NPN,

2 / bus,
1 / bus,
as required,
1 / bus,
as required.

Necessary tools:
Regular hand tools (sockets, wrenches, etc.), 1”, 1-3/8 wrenches (for removing/installing fittings).

06-12-2012

Work instruction number: L3/FSV-098
L4/QUA-003

Revision: Initial

Date: 05/22/2012
Revision: Initial
2/8

LACMTA: Air Compressor Suction Line Rework

SAFETY PRECAUTIONS MUST BE FOLLOWED ACCORDING TO ACCEPTED INDUSTRY
STANDARDS AND LOCAL/PROPERTY REQUIREMENTS.
1.
2.
3.
4.

Park the bus and apply the parking brake.
Turn off main battery disconnect switch.
Open rear engine compartment access door.
Disconnect the air intake silicone elbow from the charge air cooler (CAC) pipe. Turn the elbow
up and cover it to prevent from contamination.

5. Remove the engine hatch underneath the rear settee seats.
6. Disconnect silicone hose at the CAC pipe. Cover the exhaust port of the CAC to prevent from
contamination.
7. Cut the CAC pipe 5” from the mounting clamp with a reciprocate saw.
06-12-2012
8. Remove the two pieces of CAC pipes.

Work instruction number: L3/FSV-098
L4/QUA-003

Revision: Initial

Date: 05/22/2012
Revision: Initial
3/8

LACMTA: Air Compressor Suction Line Rework

9. Disconnect compressor suction hose from the air intake pipe.

10. Remove fitting from the air intake pipe.

06-12-2012
11. Install plug into the air intake pipe.
12. Install the 90º elbow fitting into the new engine side CAC pipe.

Work instruction number: L3/FSV-098
L4/QUA-003

Revision: Initial

Date: 05/22/2012
Revision: Initial
4/8

LACMTA: Air Compressor Suction Line Rework

13. Before installing the new CAC pipes, ensure that they are cleaned and free of contamination.
14. Install new CAC pipe piece into the silicone elbow at the engine intake side. Torque the clamps
to 100 in-lb.

15. Install silicone hose at the CAC side. Torque the clamps to 100 in-lb.
16. Install silicone hose between the two CAC pipe pieces with clamps. Torque the clamp to 100
in-lb.

06-12-2012

17. Secure the engine side CAC pipe with the original U-clamp to the original mounting bracket.

Work instruction number: L3/FSV-098
L4/QUA-003

Revision: Initial

Date: 05/22/2012
Revision: Initial
5/8

LACMTA: Air Compressor Suction Line Rework

18. Cut to fit the original compressor suction hose to the fitting on the engine side CAC pipe.
Replace hose if required.

19. Install clamp to the suction hose of the compressor hose and torqued it to 100 in-lb. Ensure
that the hose is not kinked or rubbing.
20. Reinstall engine hatch underneath the rear settee seats.
21. Remove tools and unused parts from work area.
22. Clean out bus.
Installing Turbo Protection Valve on the Air Dryer
The turbo protection valve is required to be installed on the air dryer to protect the Cummins engine
from boosted air power loss. Follow the instruction written in Graham White’s official bulletin # RK
06-12-2012
CKX5 (see attached at the last page).

Conversion kit #CKX5
Work instruction number: L3/FSV-098
L4/QUA-003

Revision: Initial

Date: 05/22/2012
Revision: Initial
6/8

LACMTA: Air Compressor Suction Line Rework

After completing the rework on the air dryer:
23. Remove all the tools from work area.
24. Check for completeness of work.
25. Turn the main battery disconnect switch(es) on.
26. Start the bus and make sure that the air compressor is working correctly. Check for leaks.
27. Record bus number, date of repair and name of technician who completed the work.

06-12-2012

Work instruction number: L3/FSV-098
L4/QUA-003

Revision: Initial

Date: 05/22/2012
Revision: Initial
7/8

LACMTA: Air Compressor Suction Line Rework

06-12-2012

Work instruction number: L3/FSV-098
L4/QUA-003

Revision: Initial

Date: 05/22/2012
Revision: Initial
8/8