NEWS | May 13, 2021

HEMTT, PLS: Put a Stop to Stop Bolt Woes

PLS
Photo by Capt. Cain Claxton
 
Do you have a HEMTT M1120A4 LHS or PLS M1075A1 truck? If you do, then you know the enhanced-container handling unit (E-CHU) rear slider positive stop bolts can sometimes get damaged and even sheared off, leading to maintenance downtime.
 
Positive stop bolt on rear slider
Positive stop bolt on rear slider
 
Avoid the problem by replacing the two (2) positive stop bolts located on the rear sliders at the back of trucks with a rubber bumper assembly. You can order a single rubber bumper assembly using NSN 5340-01-693-9335, and you’ll need two (2) bumper assemblies to perform this optional upgrade.
 
Rubber bumper assembly installed
Rubber bumper assembly installed
 
Important note:
The assembly cannot be used on the M1074 PLS or a PLS with the Universal Power Interface Kit/Engineer Mission Modules (UPIK/EMM) water distribution system. Also, they cannot be installed on base-model M1075 PLS trucks with serial numbers 86372 and below.

When you’re installing the rubber bumper assembly, be sure to follow safety guidelines in TM 9-2320-326-13&P (Sep 20) for your HEMTT or TM 9-2320-319-13&P (Feb 19) for your PLS. The install requires at least two (2) people.
 
Installation Instructions
 
To install the rubber bumper assembly:
 
  1. Raise the E-CHU slider.
  2. Support the E-CHU slider in the raised position with large jack stands.
  3. Remove the stop bolt and nut. If there’s severe damage to the bolt, it may need to be extracted.
  4. Use a wire brush and non-corroding solvent to clean the threads in the E-CHU receiving plate.

    NOTE: If the threads are damaged, then you’ll need to use a thread tap. Once the threads are dry, put some blue sealing compound on them. You can get a 50cc bottle using NSN 8030-01-014-5869.
     
  5. Place the spacer (washer) over the stem of the rubber bumper.
  6. Use a strap wrench to tighten the bumper assembly.
  7. Carefully remove the jack stands and lower the E-CHU slider.
  8. Use these same steps for the other side.

Make a note until the TMs are updated.