M998 HMMWV: Project Status
| 12/21/1999 | Bought the truck. While attempting to drive the truck to the truck scales to get a weight certificate, it stalled and refused to start (it started working again later). I had it towed to the hangar where I keep my M109A3 shop van, and I plan to start working on it after Christmas. It appears to have intermittent electrical and/or fuel system problems, but the engine sounds good and does not smoke. |
| 1/2/2000 | The electrical problem may have been caused by bad battery connections and loose alternator belts. The fuel problem will be harder to fix, because it looks like the fuel injection pump needs to be rebuilt. |
| 1/16/2000 | I finished replacing the fuel injection pump today. It runs! Replacing the pump is a big pain in the butt. It's necessary to remove the intake maniford first, and it's not easy to work on a HMMWV engine. I don't think the truck will need too much more work to be fully road-worthy. I bought a 4-passenger top kit and cargo area cover, and the mirrors should be here in a few days. I picked up a take-off fording exhaust stack, but I still need an intake snorkel. |
| 1/22/2000 | The truck seems to be running pretty well now. I gave it a bath, installed the mirrors and wiper arms, bolted on a beat-up surplus fording exhaust stack, and began working on installing the soft top. The connection between the battery current shunt and the alternator/chassis ground cable was loose, and made some pretty sparks. Monte Bowe's truck had the same loose connection, so maybe it's a common problem. I can't finish installing the soft top until I get some replacement wellnuts for the windshield frame and B pillar. I'll also do without the cargo area cover for a while, until I fabricate the metal plates which reinforce the body around the mounting brackets. |
| 1/26/2000 | After servicing the parking brake, I took my first "real" on-road trip in my HMMWV late tonight (that short first trip out of the auction house yard, followed by a stall and a tow, doesn't count!). I just went down to the nearest gas station, hopped on the freeway briefly, and returned to the hangar (about 10 miles round trip), but I'm pretty happy that the engine ran and nothing important fell off. I think it's just because of the tread pattern on the military tires I'm running, but the truck really wants to wander around on rough pavement. |
| 1/28/2000 | The HMMWV makes it home! My M998
finally made the 30-mile-long trip home from the hangar
where I've been working on it for the last month. I
started around 9:30 PM, taking a chance that the darkness
wouldn't be a problem in order to avoid heavy traffic.
Most of the trip was on a very hilly freeway through an
uninhabited stretch of mountains. At least one wheel seems
to be badly out of balance, so I had to keep my speed
under 55 MPH so the truck wouldn't get too squirrelly.
Several times on uphill segments, the engine started
making a loud roaring sound. I think it was
probably the fan turning on, but the jury's still out.
There was a plastic-burning smell, and I have not found a
cause for it yet (maybe a slipping belt?). I pulled over
three times at call boxes to count the wheels, look for
smoke, see if any of the tires seemed too hot, let the
engine cool a bit, etc. Two of my stops were right before
toll booths, so at least I was in lighted areas those
times. All in all, it was an exciting trip!
Upon arriving home, I managed to get the truck into my garage without removing the fording exhaust stack or hitting any walls... I was a bit surprised that I actually shoehorned it in! I did need to detach the garage door opener carriage to get the door open far enough to clear the exhaust stack. My downstairs bedroom (and future radio room) has been extended into the garage, so there's really only room for one vehicle... and a HMMWV is a bit more than one vehicle! Inspecting the truck after my arrival, I discovered that one of the brand new grade-8 locknuts I used to re-fasten the exhaust crossover pipe cracked in half... that's a puzzler, because I even torqued them to spec with a torque wrench. I noticed a bubble in the plating on the lower metal coolant pipe (where the drain cock is). Light finger pressure crunched it, and a few drops of bright green coolant came out! Eeeek! The radiator hoses feel pretty crunchy, so I think I ought to just replace that pipe (I bet it isn't cheap!), all of the radiator hoses and the thermostat, and flush the radiator. I also want to test the fan to make sure its clutch works right. I plan to disassemble all of the wheels, remove the run-flats, replace tires as necessary, and have them balanced. It'll probably be a while before my truck takes its next trip... between the bad smell and the rust-through I found on that coolant pipe, I think my truck was lucky to make the whole trip under its own power! I bet my neighbors will freak when they see that HMMWV
in my garage... hee hee hee!
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| 2/3/2000 | I finished installing the cargo area cover tonight. The
truck looks pretty sharp, now! The right rear eyelet on
the rear curtain won't stretch far enough to go over its
footman loop, so I may need to move the loop over a half
inch or so. I think that the burning plastic smell that
showed up on the drive home was caused by a plastic label
I found on the side of the muffler (which appears to have
been replaced). I probably hadn't gotten the exhaust
system hot enough to cook it before. Folks tell me that
the loud roar is normal, and is caused by the
engine cooling fan, which is controlled by a hydraulic
clutch and a solenoid valve.
Yes, my neighbors did, in fact, freak.
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| 2/5/2000 | While lubing the chassis, I discovered that the bolt holding the left radius rod (like a tie rod, but sets the toe-out of the rear wheels) to the chassis was very loose, allowing the rod to rattle around. After jacking up the left rear wheel, I found that I could easily "steer" it about 1/2". Yikes! That would sure explain why the truck wanted to wander all over the place on the trip home last week. It would also explain why the left rear tire is worn out, while the other three look pretty good. I tightened the bolt back up, and I guess I'll be learning how to do a 4-wheel alignment soon! On a brighter note, all four pairs of ball joints seem to be OK. |
| 2/27/2000 | This afternoon, I finished disassembling, inspecting and
remounting the right rear tire and both front tires. I
wanted to remove the runflats, and also inspect the tires
for runflat damage, so I would know how many new tires I
will need. The left rear tire needs to be replaced; it's
worn out by the alignment problem, and it has too much dry
rot for use as a spare. I didn't bother removing it; I'll
do that when I get a replacement. The other three tires
look OK on the inside, but the front right tire has a
1/16" diameter, 3/16" deep hole in the sidewall.
The hole doesn't go all the way through, and doesn't leak,
but that tire might want to become the spare, anyway.
Remaining tasks:
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| 3/26/2000 | It's been a while since I updated the status page, but
I've been busy. In no particular order:
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| 3/29/2000 | I decided to take a few days of vacation to work on my truck. Today, I picked up a couple of new tires I ordered ($300 each... Ouch!), installed a new lower coolant pipe, and flushed the radiator. I backed the truck out of the garage to run the engine right as the neighbors' kids were getting home from school. My house was very popular today! I let the kids climb over the truck, because I knew they'd never leave me alone otherwise. I can go back to being grumpy tomorrow. |
| 4/1/2000 | I've been busy in the last few days. I had planned to
replace the outer end of the left radius rod (the same rod
which was loose before, and thus would need to be
adjusted), because its dust boot was torn wide open. I was
unable to get it to budge in the adjuster sleeve. After
hours of torching, Liquid Wrenching, hammering and
cussing, I managed to get the other end to turn about a
half rotation... I gave up, and had
George Pretty express me
a whole new rod (I'd rather waste my money than my blood
and skin!), which I received this morning. I put plenty of
anti-seize on its threads, and it was easy to turn by hand
after installation. Ironically, it was almost the correct
length when I installed it, and the right radius rod
needed the most adjustment. Luckily, I got its sleeve to
turn with some Liquid Wrench, a bit of rapping with a
hammer, and all of my weight on a pipe wrench.
I finished the alignment today, and over the last few days I've also replaced both front tires, installed the radio tray, mounts, antenna bases, and wiring, re-installed the transmission hump padding, bolted an ammo box to some existing rivnuts on the hump between the front seats for use as a glove box, removed the cargo bulkhead (it turns out that it interferes with the rear seat transmission hump padding), changed the fluids in both differentials and the remaining hub gearbox, and made lots of other minor fixes. I think that I'll just need to balance the wheels to get the truck fully road-worthy! I hope I have enough energy left to do that tomorrow. While test-driving my truck today (for the first time in months!), I noticed that there seems to be a lot of gear noise coming from the back of the truck... I hope that's normal! I sure got some funny looks driving that HMMWV around the neighborhood! (Hee-Hee!) Future projects include installation of backup lights (waiting on connectors and a crimper), installation of the radios (waiting on the radios and one antenna whip element... the rest is all there, and they should just drop in the mounts), fabrication of a front license plate bracket (cable ties for now!), looking into a very slow leak from around the transmission, mounting a spare tire (I've put that off until I have a pro take a look at the non-penetrating sidewall hole in the tire I plan to use, and tell me whether it should be patched or left alone), and fixing some butchered and/or decayed wiring around the alternator. I think all of the major stuff is almost out of the way, other than any new bugs which might get shaken out during the next 500 miles or so. |
| 4/2/2000 | I didn't have enough strength left to balance the wheels today, so I changed the transfer case fluid and the transmission fluid and filter instead. That was a messy job! I've been told by an experienced HMMWV rebuilder that my rear-end noise is normal, so I guess my truck is fully road-worthy, except for needing its wheels balanced. I'll do that soon, but I don't see why I shouldn't drive it to work tomorrow. WOO-HOO!! I took it for a 10-mile test drive this evening, and it seems to be running well. |
| 4/15/2000 | Since the last entry, I've finished installing the radio (an AN/VRC-47, a member of the VRC-12 series of radio sets, and consisting of an RT-524A transceiver and an R-442 auxiliary receiver), installed backup lights, and balanced the wheels. I tried to mount the spare tire after the tire shop looked at it and determined that the sidewall hole didn't go all the way to the cords. Unfortunately, the surplus wheel I bought a while back failed the feeler gauge test. I recycled it as a portable antenna base; see the pictures page. To secure my vehicle, I decided to use a Pit Bull Tire Lock. Its jaws didn't open quite far enough to go around those big HMMWV tires, but I made it work by cutting off the protruding part of the steel core from the inner (larger) jaw. The backup lights are from an M1035 HMMWV two-litter soft-top ambulance. They're not correct on an M998, but I think they make the truck safer to drive, and at least they're from a HMMWV. I tapped power for them from the horn, so that the backup lights will only operate when the lighting system is turned on (just like the HMMWVs which are supposed to have them). I'll add new pictures showing the antennas, radios, intake snorkle and backup lights someday, when I get around to it. My truck seems to be running great! |
| 5/7/2000 | Last Thursday, I drove my HMMWV up to the annual
Military Radio
Collector's Group meeting in San Luis Obispo, CA, about 250
miles north of my home. It was a lot of fun, and I happened to
meet many other HMMWV collectors. Unfortunately, it looks like my
truck developed a head gasket leak, so it didn't make it back
home. I had it towed to the workshop of Bob, an expert HMMWV
rebuilder in nearby Santa Maria, CA (about 200 miles north of my
home), and he's agreed to take on the job of replacing the head
gaskets. Since replacing the fuel injection pump is about 3/4 of
the same job as replacing head gaskets, I know that I
could do the job myself... and I also know that I don't
want to!  Bob says that the noise coming from my rear end is
not normal. That's both good and bad... it means that I'll be
doing some more repair work once my head gaskets are replaced and
I drive my truck back home, but it also means that I can make that
!@^* noise go away! On the brighter side, even with a leaking head
gasket, my truck still starts more easily and runs better than
most of the other HMMWVs I've seen. I'm crossing my fingers that
I'm just working the last few kinks out of it now.
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| 6/25/2000 | My truck's out of the truck hospital, with a new pair of (surplus) cylinder heads and new head gaskets! I'll drive up with a friend of mine next weekend to pick it up. A few of its friends threw it a party to celebrate it's successful recovery. Once it comes home, it'll need a bit of rear differential surgery, but it's getting pretty close to being in top health. While I have the gearbox out, I might as well service the rear CV joints and replace their boots. I plan to do the same to the front, but I figure I'll need to drive it a bit more first once I get the rear end all fixed up. I can't wait to get my truck back home! While I'm up in Santa Maria, I'll definitely make the trip up to Jocko's for some of the best steaks in the world. |
| 7/7/2000 | I drove my truck home last weekend. It's great to finally have it
back in my own garage! It runs great at speed, but it now smokes
and runs roughly at idle, especially when cold. I hope that new
problem won't be hard to fix. It has developed a power steering
pump leak, and I need to replace one of the alternator brackets. I
plan to do both of those things before I do anything else. Then, I
need to flush the cooling system and refill it with the right
antifreeze mixture, and then get to work on the rear diff. After
that, I want to install the 3-point seatbelt mod (that's neither
cheap nor easy!), and then work on lots of other little things. It
never ends... I
replaced the shorted windshield washer pump with a NOS
replacement, but I haven't done anything else to it. I think I'll
let it sit in the garage for a while before I get started, while I
work on other neglected projects. I'm kinda sick of dumping time
and money into it for now, so it's time to take a little break!
I'm sure it won't be too long before I'm swinging wrenches at it
again.
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| 7/29/2000 | I ignored my HMMWV for a spell, while I worked on my commercial driver's license for my 2.5-ton van (and that's still in progress!), but I've finally started working on it again. I pulled out the alternator a couple weeks ago, repainted it because of some surface rust, and replaced the missing fan guard. That wasn't much work, but today I got serious, pulling out the power steering pump and cleaning and rebuilding it. Its seals were all shot, but it looks OK otherwise. The seals kit is pretty cheap, but it takes a fair amount of labor to pull it out, clean it up, and replace the seals. Next time I work on it, I'll install the power steering pump and alternator, and fix some ratty alternator wiring. My truck should be running again then, so I can flush the cooling system and go get some fuel... then it goes back up on jack stands so I can rebuild the rear diff! I haven't decided whether I'll do that myself or take it to a diff shop. As long as I have it out, I'll probably replace the rear CV boots and check out the rear CV joints. |
| 8/5/2000 | I got my truck back together today, and flushed the cooling system. It felt good to drive it again after a month, but I don't plan to drive it much more until I rebuild the rear diff. While flushing the cooling system, I discovered that both of the 3/8" hoses which run from the high spots on the radiator and the engine to the surge tank were plugged up at the surge tank nipples. These hoses let air escape from the radiator and engine and go to the surge tank, rather than getting trapped. In the "rinse" cycle of the chemical flush, I got about a mile from home and then my temperature shot up to 240°F. I think there was a big pocket of trapped air in the radiator, and then when my thermostat opened up it burped up to the surge tank and the water level in the engine dropped. Now that they're clear, I can get the coolant level right on the first try. The next step is to rebuild the rear diff, but I might wait a while before I start spending time and money on that. |
| 10/20/2000 | Well, I finally fixed that rear diff, and my truck is
fully road-worthy again! I took the diff in to the local Hummer
shop to have it repaired. One of the bearings on the input shaft
broke, but the gears were all still OK. I had them replace all of
the seals and bearings. I reinstalled the diff a couple days ago,
and test-drove the truck this evening. No more ear-plugs!
Woo-hoo! It's still hard to carry on a conversation in
this truck, but now that the rear diff isn't howling any more, I
no longer need to wear hearing protection in when I drive it.
I guess the next major task is to install the 3-point seat belt modification. There are a few other minor things to do to it, too, but the truck is basically fully road-worthy now! |
| 10/27/2000 | I've suspected for a while that my brake light switch wasn't
working quite right. I temporarily installed an indicator light so
that I could see when my brake lights come on while I drive the
truck. Due to pitted contacts (I'm guessing), I cannot adjust the
switch to turn the lights on fully with light brake pedal
pressure, but turn them off when I release the pedal. Last
weekend, I made a bracket out of some hunks of metal and
temporarily installed a snap-action lever switch in place of the
original switch. It works well, but isn't waterproof, and isn't
very sturdy. I have the right switch on order. I'll also replace
the plastic bushings on the brake pedal mounts, because one is
broken. While I'm at it, my truck needs a new hand throttle cable,
too.
Today, the seat belt latch at the driver's position finally gave up the ghost. The other three aren't far behind, judging by the condition of their plastic parts. My parts dealer doesn't have the 3-point upgrade kit for the front seat in stock right now, so I just temporarily replaced the driver's seatbelt with a cheap non-retracting belt from Pep Boys. |
| 11/12/2000 | My truck still smokes and rattles a bit more than I like when
started cold, but otherwise it's running really well. I'll check
the glow plugs a bit more carefully soon. If that's not the cause,
then I'll just live with the smoke. I replaced the bad brake pedal
switch. I thought one of the brake pedal bushings was broken
because of some play in the pedal, but it turns out that the play
is just because the hole in the pedal bracket is a bit larger than
the pivot pin. I replaced the bushings anyway as long as I had it
apart. I also discovered that my hand throttle cable wasn't in
such bad shape, after all, so I guess I didn't need to replace it
after all, but as long as I bought a new one anyway... I need to
stop being so picky and just drive the @^$! thing!
I got a surplus brush guard from
eBay recently, and I installed
it tonight. The guard and one of its brackets are a bit bent, but
I figure that give it character. The guard is one of those wimpy
early-model military ones, but it should work out just fine since
I don't plan to do any really serious off-roading. No pictures
yet, so you'll need to wait until I have another reason to take a
new picture of the truck if you want to see it.
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| 1/21/2001 | Well, it looks like my brand new brake light switch has failed
just like the last one, so the brake light won't come on unless I
put a lot of pressure on the brake pedal... much more than I use
in a normal stop. If I readjust it to turn on with light pressure,
then it won't reliably turn back off. I believe that this is a
design flaw. A rotary switch should not be used in that
application, because the edges of the contacts will arc, heat up,
and get pitted when the brakes are lightly applied, thus creating
a high-resistance area between "on" and "off".
I've put that home-made bracket and snap-action switch back in.
I'd like to replace it with something a bit less cheesy. When I
do, I'll update the modifications page
with details.
I also installed my surplus military GPS receiver and its external antenna recently. The antenna is on a home-made bracket mounted behind the snorkle support bracket, and the GPS receiver hangs from the roof just to the right of the driver's seat. While I was at it, I added a dome light to the bracket that I made to mount the receiver. That's a lot nicer than fumbling for a flashlight in the dark. Surprisingly, this installation required no holes or other permanent modifications. I'll describe this on the modifications page when I get around to taking some pictures. |
| 1/2/2004 | I'm converting my truck to an M1037 shelter carrier. I have an S-250/G shelter containing an AN/GRC-122B radio teletype set which will be mounted on the back of the truck. This conversion includes replacing the rear suspension with heavier-duty components, mounting a special frame in the bed, relocating the tailgate to the end of that frame, and other modifications. The conversion is described in more detail on the modifications page. |
