NUMBER: SB-121-023

DATE: 9/10/02
MODEL: CH, CL

(Does not apply to Meck Trucks Australis)
(Supersedes Bulletin SH-121-125 dated 2/142)

REAR CROSSMEMBER REINFORCEMENT — CH AND CL WITH CH
STYLE REAR CROSSMEMBERS

Cracks may develop in the rear crossmembers {assembly part Nos. 48OL51BM and
48Q154AM) used on CH and CL model chassis equipped with AL II suspensions, Typically,
these chasele are used In tanker earvice, and the cracks may likely ocour just inboard of the
inner Huck™ bolts that fasten the lowar bracket to the main cantar section. If aacks develop,
the crezamember malin canter section must be raplaced. Additionaly, to prevent cracks from
developing In the replacament crossmembers, it ia recommandad that additional
relnforesment plates be Installed to the canter main secten of the crosamember where it Is
secured to the lower bracket. Also inspect tha lower bracket for damage and raplace as
necessary, Part numbers for replacing the crossmember assemblies and installing the
edditional reinforcament ates ara as follews:

43GL518M Gressmember Assembly stthout aide Channel Ralntarcement

Oty. Part No. Deacription

1 POLS126M Crosamemiber, malin conte: section
2 GOW413 4M Lower braciust, crossmarnber

8 4AM Pan, Huck-FH

4 1594M1 Collar, Huck-Fit

4$0L215N2 Croaamembar Aseombly with inside Channel Reinforcement

‘Oty. Part No. Description

1 9OL5124Mz2 Crosamember, main center section
2 GOLATIIAM2 Lower inackal, erossmembar

a 4AM Pin, Huck-Fil

6 15SaN1 Galler, Huck-Fit

43051663 Heavy Coty Cromamember Assembly without Inside Channel Reinfioreamant

Gy. Part Mo. Gevcrigitan

1 512462 Crpsmember, main canter section

z SOL41914M Lower breaches, oad member

z $01 4145¢M End bracket, crossmember main canter seciion
5 44ANQ Fin, Huck Fit

3 1504M1 Collar, Huck-Fl

SERVICE PUBUCGATIONS, ALLENTOWN, PA 12105

S8-121-023 — Page 1 of

Ge

@MACK TRUCKS, IMG, 2068

4¢0LE44M Croeamamber Asgembly without aide Channel Reinforcement

Gty. Part Mo. Description

1 Pals 124é Crosktiemiee, main canter section
2 BOL41794M Lover bracket, croesmember

a 4AM2 Fin, Huck-FH

8 1594M1 Collar, Huck-Fit

S20L04AN9 Crosememizer Agpambbly with ingkie Channel Reinforcement

Oty. Part No. Desorption

1 SGLS124NG Coosemanber, main canter section
z BOLdA1TTSAM2 Lower bracket, crosemamber

a 442 Pin, Huck-FR

8 1304Mi1 Coftar, Huck-Fit

Relnforsamant plates and fasteners are as follows:

City. Part Na. Description
4 BOLA480h Plate, reinforcement
4 apa Pin, Huck-Fit

4 169AM1 Collar, Huck-Fit

Installation procedures for the crossmember assembly and the reinforcement plates am as
folkows:

1. Remove the existing croasmember from the chassis. For information concerning frame
and crossmember service, and any pertinent information covering Huck-Fit frame
fasteners, refer to the Frames, Springs and Suapension Service Menual, 14-100.

2, Install the crossmember brackets to the frame rall and secure with the proper size
Huek®-Fit frame fastanere.

NOTE

On the previous cossmember center sections (part Nos.
§QL5101BM and 9$0L51918Mé2). It was necessary to drill the
four Inner mounting holes to secure the reinforcement plate. The
new crossmembers {part Mos. 9OL5124M and 90L5124M2)
Include the reinforcement plate inner mounting holes, Drilling the
crossmenber is no longer necessary.

$8-121-021 — Page 2 of

3. Secure the crossmember main center section to the lower bracket, and the
ralnforcament plate to the crosemamber cantar section. Use B Muck-Fibe pins (part No.
44M?) and 8 collars (part No. 15941) to secure the crossmember canter section and
relnforcement plate to the end brackets, anc 4 additional Huck-Fik® ping {part Na,
44M1) and collars (1594M1)} to secure the reinforcement plate at the inner holes of the
crossmember malin center section.

Fiqpure 4 — RinForosmoent Phaty inetetietion

The number of crogsmembers used on a chassis varies by chassle design. Labor codes and
Mmecimim labor alewances for crossmember reinforcement and replacament are as follows
(refer te the illuetration below for crossmemiber layout):

Back of Cab Gomewebe Creaemener
Cree eee n i”

Figura J — Crmesmembar Lago

121 DLO 92 Reptace Back of Cab Grosamember and Crossmarnber #1 15.3 he.
121 DK 00 82 Replace Grosamernninn #4 Sz bw.
ADOITION
«141 OK O60 TL Additional time to sagiace Croamnem bar #3 2.3 br.
©4121 OX OO TL Additional time to replace Croperemizar #2 0.6 hr.

The abows times include take chargé tima, steam cisaning, reinforcement plate Installation,
fifth wheel removal when neceseary, etc.

$B-121-023 — Page 3 of 3