Service Bulletin - June 2023
SAF Tire Pilot Plus™ (TPP) Inflation System
Hubcap Window Replacement
Tire Pilot Plus (TPP) grease style hubcaps on axles produced
after January 2020 through May 2023 (date code 20 001
through 23 150) may have been manufactured with nonconforming hubcap window material. This can result in failure
of the hubcap window, exposing the wheel end to the
environment. We recommend replacing these windows at the
next service interval or if a failure occurs. All hubcaps
windows on a single trailer should be replaced at the same
time. Replacement window kit part number is 48100816. Each
kit contains 4 window replacements.
The following instructions provide the necessary information
for identifying and replacing the plastic hubcap window on
grease style hubcaps.
Hub may be pressurized, failure to vent
the hub prior to servicing could result in
minor or moderate injury.

TPP Hubcap Window - Preparation for
Service
PREPARATION:
1.

When working on a trailer before completion of, or
during the procedure on the next page, make sure to
have the air supply and power to the trailer turned off.
Any residual pressure in the hub assembly should be
relieved by opening the hub lube fill port or loosening
the hubcap itself (hubcap removal is not required). It is
necessary to have the hub fill plug rotated between the
9 and 3 o'clock position, to prevent semi-fluid grease
from coming out when opened.

2.

Be sure to keep body clear of the hubcap faceplate
area until the hub is confirmed to not have any stored
pressure. In addition, allow pressure to leak out through
the center axle vent until no audible air can be heard.

3.

If any troubleshooting or service is required with air
supplied to the trailer, disconnect the wiring harness
from the TPP electronic controlled module or mechanical
regulator assembly before pressurizing the air system and
working near the hubcap window faceplate area.

XL-AA20122SB-en-US Rev B · 2024-02-16 · Amendments and Errors Reserved · © SAF-HOLLAND, Inc., SAF-HOLLAND, HOLLAND, SAF,
and logos are trademarks of SAF-HOLLAND S.A., SAF-HOLLAND GmbH, and SAF-HOLLAND, Inc.

1

TPP Hubcap Window Replacement

TPP Hubcap Window – Inspection &
Replacement

Figure 1

INSPECTION:
4.

Before performing any maintenance on the trailer, set the
parking brake and block the tires.
Failure to set the parking brake and
chock the tires prior to beginning
maintenance could allow the vehicle
movement which, if not avoided, could
result in death or serious injury.

5.

Check date code range, on the axle serial tag, to see if it
falls inside the affected date range, date codes 20 001 and
up. (Figure 1).
Figure 2 illustrates the grease style plastic hubcap
window that will need to be replaced.
Figure 3 illustrates the aluminum replacement hubcap
window with duck-bill vent.

6.
7.

DATE CODE (YY DDD)

Figure 2

Figure 3

2

XL-AA20122SB-en-US Rev B · 2024-02-16 · Amendments and Errors Reserved · © SAF-HOLLAND, Inc., SAF-HOLLAND, HOLLAND, SAF,
and logos are trademarks of SAF-HOLLAND S.A., SAF-HOLLAND GmbH, and SAF-HOLLAND, Inc.

TPP Hubcap Window Replacement

REPLACEMENT:
1.

Figure 5

Loosen and remove the window retainer screws using a
T20 Torx bit and save screws (Figure 4).

NOTE: Use of a power or air tool is NOT recommended
for the removal of the retainer screws.
2.

Remove the aluminum retainer from the hubcap assembly
and save (Figure 5).

3.

Remove the hubcap window plate from the assembly
(Figure 6).

4.

Position the new aluminum window with duck-bill vent
on the window seal (Figure 7).

Figure 6

Figure 4

Figure 7

XL-AA20122SB-en-US Rev B · 2024-02-16 · Amendments and Errors Reserved · © SAF-HOLLAND, Inc., SAF-HOLLAND, HOLLAND, SAF,
and logos are trademarks of SAF-HOLLAND S.A., SAF-HOLLAND GmbH, and SAF-HOLLAND, Inc.

3

TPP Hubcap Window Replacement

Replace the aluminum retainer ring on the hubcap
assembly. Make sure to align the gasket if it has shifted
position (Figure 8).

6.

Install the window retainer screws (Figure 9).

7.

Torque the window retainer screws to 18-23 lb-in in an
opposing pattern (Figure 10).

Figure 8

NOTE: DO NOT send hubcap windows back. Scrap the
plastic window once the replacement is complete.
For this procedure SAF-HOLLAND will reimburse 1/2 hours of
labor per trailer. Once the procedure is done, you will need
to supply:
„

trailer make

„

trailer VIN

„

trailer in-service date

„

both axle serial numbers

„

suspension serial number

„

date of window repair

„

authorization number

Figure 9

to SAF-HOLLAND warranty at [email protected] for
labor reimbursement. We apologize for any inconvenience
this may have caused. This program will remain open until
December 2024. SAF-HOLLAND is committed to serving our
customers with quality products.
If other warrantable issues are found during the replacement
of the hubcap window, a separate claim must be filed for
those items.

Figure 10

SAF-HOLLAND, Inc. · 888.396.6501 · Fax 800.356.3929
SAF-HOLLAND Canada Limited · 519.537.3494 · Fax 800.565.7753
Western Canada · 604.574.7491 · Fax 604.574.0244
SAF-HOLLAND Mexico · +(52) 55.5362.8743 · Fax +(52) 55.5362.8743
www.safholland.us

XL-AA20122SB-en-US Rev B · 2024-02-16 · Amendments and Errors Reserved · © SAF-HOLLAND, Inc., SAF-HOLLAND, HOLLAND, SAF, and logos are trademarks of SAF-HOLLAND S.A., SAF-HOLLAND GmbH, and SAF-HOLLAND, Inc.

5.