NEWS | Dec. 19, 2019

M1000 HET Semitrailer: Installing New APU Hydraulic Pump

Mechanics, there’s a new hydraulic motor pump, NSN 4320-15-010-3304, available for your M1000 HET semitrailer’s auxiliary power unit (APU).
This new pump is a different design and replaces the old, black cast-iron pump, NSN 4320-01-331-8742. When you receive the new pump, you’ll notice it has an aluminum mid-body section and comes with the hydraulic inlet and outlet ports about one inch closer to the pump’s mounting cap screw holes. That makes it a little tricky to remove and install when following the current instructions in WP 0107 of TM 9-2330-381-13 (Oct 09, w/Ch 1, Apr 15).
Some mechanics get around this by continuing to order the old pump. But stock is running short and soon only the new pump will be available.
Installing the new pump is possible. It just requires a few changes to the removal and installation procedures. Here are the coming changes:
In Step 4 of WP 0107-2, insert a NOTE that it may be necessary to remove the pipe-to-tube adapters in order to allow the mounting cap screws (Item 3 in Fig 1) to be removed.
In Step 2 of WP 0107-4, insert a NOTE that it's necessary to place the right-side mounting cap screw (Item 5 in Fig 1) and lock washer (Item 6 in Fig 1) on the pump's mounting hole before the right-side pipe-to-tube adapter is installed. Installing the right-side pipe-to-tube adapter first prevents the right-side mounting cap screw (Item 3 in Fig 1) from being installed.
Make a note of these changes until the TM is updated.