FSB 371-046

Mack Trucks, Inc.
Greensboro, NC USA
Field Service Bulletin
Trucks
Date
Group
No.
Release
Page
3.2014
371
046
01
1(2)
Frame Rail Ground Stud
CHU, CXU, GU, TD
FSB 371-046, Frame Rail Ground Stud
(March 2014)
On certain Mack Trucks built from 01/01/2010 to 10/7/2013 the main ground stud, located on
the frame rail behind the battery box, may have been improperly torqued. This improper
torque may have allowed corrosion inhibitor to get between the ring terminals which may
cause multiple fault codes and/or intermittent issues.
To correct this problem, follow the procedure below:
You must read and understand the precautions and guidelines in Service Information,
Function Group 30, "General Safety Practices, Electrical and Electronics" before
performing this procedure. If you are not properly trained and certified in this procedure,
ask your supervisor for training before you perform it.
Repair
1 Secure the vehicle for service by parking it on a flat level surface, applying the parking
brake, chocking the rear wheel, and placing the transmission in neutral.
2 Disconnect all cables from the negative (ground) battery terminals to prevent personal
injury from electrical shock and prevent damage to electrical components.
3 If necessary, clip cable ties and remove battery cutoff switch bracket fasteners and tie out
of the way.
4 Check torque of nut on ground stud.
Note: Some trucks may have ground studs secured with double nuts. Make sure the
check torque is applied to the inside nut.
a. If the nut torque is 40 Nm≥ (30 ± 4 ft lbs). No further action required. Proceed to step
10 of repair procedure.
b. If the nut torque is < 40 Nm (30 ± 4 ft lbs), proceed to step 5.
5 Remove the nut and cables from the ground stud.
6 Clean residual corrosion inhibitor and debris from all ring terminals and stud.
7 Reinstall the ring terminals and nut. Torque to 40 Nm ± 6 Nm (30 ± 4 ft lbs)
8 Coat all connections with corrosion inhibitor or similar product.
9 If necessary, reinstall battery cutoff switch bracket fasteners. Install previously removed
cable ties.
10 Install all the previously removed cables to the negative (ground) battery terminals.
PV729-FSB371-046_M
USA63491
Mack Trucks, Inc.
Field Service Bulletin
Date
3.2014
Group
No.
Release
371
046
01
Page
2(2)
Reimbursement
This repair may be eligible for reimbursement if a product failure was experienced within time and mileage limits of
the applicable Warranty coverage. Reimbursement is obtained via the normal claim handling process.
Claim Type (used only when uploading from the Dealer Bus. Sys.)
01
Labor Code
Inspection and Repair
7238J-01-80
0.3 hrs.
Causal Part
983716