Seals Can Be Damaged When Removing Or Installing The Cut-Out Cartridge Valve From The Body Of The Accumulator Charging Valve Group Caterpillar

THIS TIB REPLACES THE JULY 26, 1995 OFF-HIGHWAY TRUCK TIB, COMPONENT CODE 4307. DESTROY THE JULY 26, 1995 TIB. IT WILL NOT APPEAR IN THE QUARTERLY INDEX

Problem:

There is a drain hole in the body (block) of the accumulator charging valve that is cross-drilled into the cavity for the high pressure cut-out cartridge valve. This hole can cut the third seal and back-up ring (from the nose end) when the cartridge valve is being installed or removed from the block.

An annulus at the cross-drilled drain hole has been added to the new block that is the body for the 120-4622 Accumulator Charging Valve Group. The accumulator charging valve groups with this annulus can be identified by either a date or the letters "XX" stamped on the side of the 120-4307 Block that faces toward the front of the machine.

Solution:

Earlier valve bodies (blocks) that do not have a date or "XX" stamped on the end should be reworked so the seals are not cut when the cartridge valve is being removed or installed. Use the dimensions shown in the illustrations to rework the valve bodies (blocks).

The 120-4622 Steering Accumulator Charging Valve Group was in effect with 793B Trucks (1HL264). The 120-4622 Steering Accumulator Charging Valve Group with the annulus is in effect with 793B Trucks (1HL303). The 120-4622 Steering Accumulator Charging Valve Group in 793B Trucks between 1HL264 to 1HL303 will also need to be reworked.

Illustration 1

Valve Body (Block)

Illustration 2

Section A-A

Illustration 3

Section E-E

Illustration 4

Detail G

COPYRIGHT 1995 CATERPILLAR ALL RIGHTS RESERVED