Usage:
M312 (6TL),
M315 (7ML),
M318 (6ES, 8AL),
M320 (6WL) Excavators
Description of Change: The platform for the M300 series Excavators is changed in order to provide better cab support. The former M10 bolts that are used on the previous machines are replaced with new M12 bolts. The M12 bolt size can sustain the recommended torque of 105 ± 10 N·m (78 ± 7 lb ft) and reduce the possibility of bolt failure.
Other changes are made to improve the platform design. New rubber mounting assemblies for the platforms allow for a more desirable clearance with the M12 bolt. The bores in the new platforms are threaded for the M12 bolt. New washers provide the recommended flexibility of the cab platform on the mounts.
Adaptable To: The new 8T-4176 Bolt (M12x1.75x90mm) is used in place of the former 8T-5436 Bolt (M10x1.50x130mm) for securing the cab to the upper structure. The new M12 bolts may not be used with the former mount assemblies and platforms. The chart lists the applications for the new platforms and mounting assemblies.
Illustration 1.
Location of the new M12 bolts.
The improved cab platform mounting is effective with M312 (6TL333-Up), M315 (7ML680-Up), M318 (6ES228-Up, 8AL1032-Up), and M320 (6WL97-Up) Excavators.
Illustration 2.
Section view of new 144-4079 Mount Assembly. See chart for serviceable part numbers.
The improved parts are designed so that washer (2) should not come in contact with outer metal (C) of the mounting assemblies. The mounting assemblies have rubber (A) internally, in order to provide more flexible movement for the cab.
Washer (2) should only come in contact with inner metal (B) of the mounting assembly so that the head of the bolt and the washer can act on rubber material (A) of the mounting assembly and not the outer metal of the mounting assembly.
The former washer has an outer diameter that was larger than the diameter of the mounting assemblies. This prevented the mounting assembly to flex with the movement of the cab.