Fuel Tank Woes

We had purchased a fuel tank for our M1038, as well as the missing straps, fuel level sender and other pertinent parts, and were ready for installation.

Top view of fuel tank ready to be installed

We were unaware, however, that the jumper between the fuel tank and the wiring harness was missing. So, using the correct Prestolite wire, wiring ends, and PET loom, we fabricated a replacement jumper. (Ensuring that it was made to military specifications).

UPDATE 3/ 24/2019: We fabricated the jumper at a 36″ length. As it turned out, the length could have easily also be made at 18″-24″ length. As it turned out, we cable-tied the excess to the fuel tank vent tube near the crossmember where the jumper connects to the harness. We suspect that should we have to remove the tank in the future, the extra length will prove “slack” to permit us to lower the tank without having to disconnect the jumper from the harness.

We were ready to install. Or so we thought. Even after removing the driveline, we found that we could not physically fit the tank into the area, as it hit the emergency brake caliper, rotor, and bracket.

We were simply unaware there was more than one main fuel tank. Our tank 2910-01-447-3911 [2910014473911] carries part number 12460105, and is easily located. As it turns out, we should have verified application through the UOC (Usable On Code) found in the parts TM in the far right side under description.

The UOC for a M998 is H13, whereas the UOC for a M1038 is H14. For practical purposes (other than differences between having a winch or not) either code would be accurate.

As it turned out, the NSN for the tank we had did not have the correct UOC, and we found the tank we required was part number 5582606, with no NSN provided for a part number. We simply had the wrong tank.

Through further research, we were able to identify a serial number split from 1 thru 44824, which uses the brake mounted against the rear differential on the driveshaft side. 2530-01-174-7441 [2530011747441].

We are well aware of operator complaints regarding this parking brake, but have found to often that operators attempt to adjust the brake from the brake handle adjustment (which is meant only to adjust for slack in the cable), and not properly adjust the brake from the caliper adjustment. We purposely chose to maintain this brake system because of our unit’s 4 digit serial number for historical purposes.

However, as noted above, we were completely unaware that maintaining this brake would require a fuel tank of limited availability.