BENDIX TCH-002-010 User Manual

Technical Bulletin

Bulletin No: TCH-002-010 Effective Date: 6/2/08 Cancels: N/A Page: 1 of 2

Subject: Retroﬁ tting Wide-Based Tires: Increased Vibration Requires

Improved Air Chamber Bracket Supports

This Bulletin addresses vehicles originally equipped with dual tires on the drive axles which are retrofitted with “wide-based” tires (also referred to as “Super Singles”).

T est data has shown that retroﬁ tting “wide-based” tires can result in higher vibrational loading of vehicle drive axles and wheel ends. As a result, the air chamber bracket supports are potentially exposed to vibrations and stresses beyond their original design capabilities.

Example of

Air Chamber

Bracket without

Gusset

GUSSET

Example of Air Chamber Bracket with

Gusset

As with all retroﬁ ts, Bendix recommends that the installer conﬁ rm with the vehicle Original Equipment Manufacturer (OEM) that the changes to be made to the vehicle are approved and obtain from the OEM any vehicle modiﬁ cations that are required (e.g. suspension clearances, etc.) before proceeding.

When vehicles equipped with Bendix foundation brake components are retroﬁ tted with wide-based tires, Bendix requires the vehicles to be further equipped with:

• Air chamber brackets with gussets (see Figure 1). If the air chamber brackets do not have gussets, they must be replaced with Bendix approved air chamber brackets with gussets. Identify the part number stamped into the support arm (see Figure 2 for location) and refer to BW7253 for the proper gusseted replacement.

• Bendix “Marion” air chamber bracket supports or other Bendix approved air chamber bracket supports, welded to the axle, are required (see Figure 2).

Failure to make all necessary changes when retrofitting wide-based tires will void the

warranty on all Bendix

foundation brake

products equipped on the vehicle.

FIGURE 1 - EXAMPLES OF AIR CHAMBER BRACKETS WITH AND WITHOUT GUSSETS

AIR CHAMBER BRACKET

PART NUMBER STAMPED HERE

“MARION”

AIR CHAMBER

BRACKET SUPPORT

(TYPICALLY

820188)

FIGURE 2 - EXAMPLE OF “MARION” AIR CHAMBER BRACKET SUPPORT

WARNING: Follow all standard industry safety guidelines when welding, including disconnection of batteries.

(Continued over)

Bulletin No: TCH-002-010 Effective Date: 6/2/08 Cancels: N/A Page: 2 of 2

FIGURE 3 - EXAMPLE OF SUPPORT WELD ARRANGEMENT

Whenever available, use the axle manufacturer’s recommendations for welding the additional “Marion” brackets - the welding notes below are shown for reference only (See Figure 3):

• E70T-5 FCA W or ER70S-6 GMAW Single Pass Process 60

F (15.50C) Minimum

Pre-Heat Temperature

• Maximum Fit up gap of 0.16 inch (4mm)

• The order of welding may be reversed or started on the opposite side

• The direction of welding may be completely reversed

Reference: Application Guideline Catalog - BW7260 Illustrated Parts List - BW7253

Available from the Literature Center at www.bendix.com and also from www.Roadranger.com.

Questions or changeover information: Call 1-800-Air-Brake (1-800-247-2725)