The HMMWV was down for over a month this summer. I was having problems with the power steering that I thought was air in the system from when I removed the cooling stack. It was hard to turn but even the brakes stopped working right. Back when I put the cooler back in I filled up the power steering with ATF, it never really ran dry or anything. I topped it up a little then just as I was pulling back in the driveway it squirted some out all over the ground ( I guess out the cap vent). That's when I noticed the brakes were not power assist any more. I tried bleeding it a couple times like the TM says but it never got better. I pulled out the a power steering tester I had for GM vehicles, but none of the fittings would fit. I found a surplus power steering test I had bought, but on first glance it looked like it wouldn't fit the HMMWV. Then I realized the two adapters were screwed together. Here's a picture of what the adapter for the HMMWV look like.
I hooked up the power steering tester according to the TM (you have to install a bypass hose as well as the tester) and followed the troubleshooting procedure.
During normal operation is showed only about 50 psi and maybe 1 gpm. When I closed the valve the pump only got up to about 600 psi. According the TM the pump was bad. I finally found a NOS genuine military part. I followed the TM and got it installed and bled. It was amazing how much better the truck drove with a good pump. I did notice with the new pump when starting the truck if you have your foot on the brake the pedal will jump back up at you when there's pressure, with the bad pump it did not anymore.
I've been wanting to add some switched to the HMMWV for lights and accessories. The boxes that mount near the fording valve look nice but I didn't want to get in the way of the valve when I get it installed. I found a neat 4 switch plate on an auction site that mounts by the door.
I found out the hard way that you should install the switches after you mount it otherwise it will not fit. There's a groove machined into the plate that keeps all the switches aligned straight. I didn't use the switches that came with it, they were nice but I wanted sealed military grade switches so I went with the cutler hammer brand. I soldered on some pigtails with packard connectors on them.
I've been experimenting with different dome lights for the truck. I ordered some BA15S led bulbs that fit in a standard dome light socket. They were advertised as 12-24v bulbs. Before installing them I hooked them to my power supply and tested them out at 26 volts to simulate the alternator charging the batteries in the truck. The current on them jumped up to .4 amps (according the power supply) by the time I got up to 24+ volts. It only took a couple seconds for them to start smoking. I guess the voltage range of 12-24 volts was a clue.
I tried them again on 12v after they stopped smoking and they actually still work. The next ones I ordered only say 24 volts, so hopefully they will actually work in a 24v vehicle.
My in progress projects now include- mounting a 24v inverter in the helmet hardtop (one of those surplus 1800w units), installing the Harris offset heavy duty antenna bracket (the hardtop was in the way, having to use spacers on the back), rear flood lights, switched 24v fuse panel (from ignition or ACC position, using a relay), switched 12v accessory power panel to run a vhf radio and CD / stereo, adding a 12v Tekonsha prodigy electric brake controller and relay box for 12v trailer receptacle, a spare tire mount for inside the hardtop that holds the tire vertical, a roof rack for the hardtop. I've installed two of the armor dome lights in the front with some simple brackets, just need to get some pictures.
I'd like to install some 24v outlets inside the truck. I was thinking about the mini twist lock kind that the CUCV ambulance has. I've also seen some that look like a light bulb socket, usually used for trouble lights and the pouch style MRE heaters. I'd like to be able to use the outlets for the hot water MRE heater, a surplus 24v electric fridge / freezer (originally for blood / medicine transport), work lights, a laptop power adapter, etc. Any suggestions? Anyone know which prong on the CUCV ambulance outlets is positive (one is silver the other is brass color)?