Document QXa2p4O51J4ngD6q949jOaBmR
PLAINTIFF'S EXHIBIT
BULLETIN
JUNE 20, 1979
\0. qio3 under brakes
FOR BRANCHES, DISTRIBUTORS AND CUSTOMERS.
CHASSIS AFFECTED ALLENTOWNBf HAYWARDS?' OAKVILLE^
DISCONNECTING ANTI-WHEEL LOCK SYSTEM (All Vehicles So Equipped)
PURPOSE To inform the field regarding legality of disconnecting or by-passing anti wheel lock function on vehicles in service.
RECOMMENDATION If the anti-wheel lock system is in good operating condition it is recom mended that it be left in operation unless otherwise instructed (e. g. by a mandatory safety cam paign). If an anti-wheel lock system is disconnected, be sure to follow the instructions given herein.
INFORMATION In October, 1978 a Federal Court rendered a decision that invalidated the necessity for anti-wheel lock equipment. This decision means that a manufacturer, distributor, repair shop or owner may legally remove or make inoperative the anti wheel lock equipment on any vehicle so equipped, regardless of date of manufacture.
Anti-wheel lock function is no longer required to meet the brake standards which the Federal Court modified. This decision does not mean that anti-wheel lock systems cannot be installed or used.
Mack Trucks, Inc. does not recommend that anti-wheel lock systems be disabled unless a condition exists that may increase stopping distances. However, some owners may want to disconnect their system. As a convenience to these owners we are providing the following instructions.
NOTE
We suggest that the disconnected wires be left intact and protected from damage so the system can be reconnected if desired.
A. Disconnecting the Anti-Wheel Lock Electrical System
NOTE
To insure complete deactivation of the anti-lock electrical system, it must be disconnected at two locations as described in following Steps 1 and 2. The procedure is the same for front and rear axle or bogie systems.
1. Disconnect the system power lead(s) at the cab circuit breaker. Lo cation of the circuit breaker and wire identification is shown in the ac companying chart. After disconnecting, tape end of wire(s) so it can not make electrical contact.
CIRCULATION
Service Manager
Shop Foreman
Night Foreman
Night Foreman
Inapector Leadman
Inapector Leadman
Inspector Leadman
Unit Over haul Room
HINTED IN U S A .
Page 1 (Continued Page 2) Service Operations, Allentown, Pa., U.S.A.
Shop Office
,9
JUNE 20, 1979
1. ANTI-WHEEL LOCK CONTROLLER 2. POWER/WARNING LEAD CONNECTOR 3. CONTINUITY CABLE (IF USEOl
NOTE
The anti-wheel lock warning light will remain lit whenever the key switch is in the run pos ition. This feature is an additional warning to the driver that the anti-lock system is inoperable.
IMPORTANT WARNING BE SURE THE NOTICE LABEL 4MR1452 (RE PRODUCED BELOW) IS AFFIXED TO THE IN STRUMENT PANEL IN FULL VIEW OF THE VEHICLE DRIVER.
NOTICE The Wheel Anti-Lock System on this Vehicle has been made Inoperative by Disconnecting the Power Supply. The Brakes are Fully Driver Controlled.
4 MR 14S2
B. Front (Steering) Axle Brakes
If the anti-wheel lock capability is removed from front wheel brakes, it is essential that the brakes do not have excessive braking ability, otherwise they may lock up and cause loss of steering control. This condition can exist on FA536 and 537 series front axles built between March 1, 1975 and June 1, 1976 and FA616D, 617D and 618D disc brake equipped front axles. These axles must be checked and if not equipped as follows, they must be modified. Consult your Mack service center.
Cam Brakes . Type 20 brake chambers . 5 1/2 in. slack adjusters . Medium friction (EE) brake lining
Disc Brakes . 17:llntensifier (Type 36 Rotochamber - Refer to Service Bulletin
Q95a under BRAKES) or as an alternative. . Install drum brakes - Consult your Mack service center.
Rockwell Front Driving Axle No change required