Fixing the 1998 HMMWV

[mrandig]

It's cranking but not starting.

Best I can tell, there's no fuel. At least there's nothing running out at the fuel / water separator valve. I had a little spurt of around 4oz. at first, but that was it. Probably just whatever was in the separator to begin with.

I don't have much going on for tomorrow, so I guess I'll figure it out then.

Tank is full of diesel. Over-filled is probably more accurate.

 

[mrandig]

I don't seem to have any vacuum on the inlet side of the fuel pump.

How was this thing even running before?

Looks like another parts order. Even if I went with AC Delco or NAPA, I can't find anything in stock close to me.

 

[mrandig]

Instead of just twiddling my thumbs waiting on parts (again), I decided to take another crack at the driver's seat, as it still wasn't sliding properly, and absolutely had no interest in raising or lowering the height.


This time, the whole thing is coming out and then coming apart. Or vice-versa, whichever is easiest...

Since the seat had been removed previously, I decided to take the base apart, beginning with the sliding section. There are four bolts that attach the rails, one for each corner. The rear bolts can be accessed by sliding the seat forward.


The front bolts are the opposite. Push the seat back as far as it will go.


A little PB Blaster is always helpful loosening things up. In this case, it was a "mega size" can, so it was actually a lot of PB Blaster.


The bolts are #6 allen head. A 13mm "stuby" wrench helps to get into those hard-to-reach places.


Upper sliding section removed.


There's a canvas seat cover underneath. This is supposed to be green, but there's a lot of dirt going on down here.


Looks like it might be OK. Besides being caked with dirt.


With the seat cover removed, it becomes a little clearer why things don't work properly.


The top seat cover velcros to a lower skirt cover.


The lower skirt cover won't come off until the base is removed. More allen head fasteners.


The base bolts directly to the reinforcements in the floor. There's a bolt for each corner.


Room gets pretty tight, but a few universal joints get the job done.


The lower skirt is shot and needs to be replaced. The upper cover should be fine with a little wash.


Here's the base removed.


And finally, we can see the floors. Once again, just when I thought things were clean, more dirt appears.

 

[mrandig]

The new fuel pump is here.


That said, I'm just not feeling it today. "Quick" projects on this truck never seem to work out that way, and I'm just not in the mood for more frustration. Maybe tomorrow.

Instead, I'm going to keep going with the interior, and hopefully I can make some progress. With both the seat and seat base removed, this will be my best chance to clean up the driver's side. This truck will never again have that new car smell, but at least I won't have to shower after I drive it around.

I've got one last piece of installation and the fire extinguisher bracket to remove.


With a 7/16" socket, everything comes out pretty easy.


There's a cross bracket that mounts to the seat bracket, and once removed, the final piece of insulation will come out.


So much dirt.


Everyone into the pool.


The wife keeps wondering where her dishwashing brushes are going.


New bracket for the fire extinguisher.


Correct replacement fire extinguisher.




All parts are getting a final wipe down before some grease, where needed, and re-assembly.


With the dirt loose, it should be easy enough to clean up with vacuum once it's dried.



Somewhere around this point, I remembered that I hadn't purchased any of the other insulation pieces. Assuming I can still find the hardware to install them (I haven't seen them for a while), I may just skip this step for the time being.

 

[mrandig]

I'm still working on the interior but expecting to be finished this afternoon.

Here's the base cleaned up and just about ready to re-install.


I had some random supplies lying around, so I figured why not give them a try. The synthetic grease is supposedly made for dusty, sandy environments.


The acid brush is for precision application.


I ended up using some light oil also. The needle tip made it really easy to control.


Here's what everything looks like finished.


Speaking of random supplies, I also had this "tub-o-towels" laying around. Not sure why or when I bought these, but I highly recommend.


The "tub-o-towels" did the trick. I'm super happy with the way the interior cleaned up.

 

[mrandig]

I still need to get the fuel pump changed out, but I did manage to finish some work on the driver's interior.

Here's the new seat, disassembled and cleaned seat base and sliders, and a new fire extinguisher.

It looks like it will be a while before I get the covers for the base, so I'm good for now.

 

[mrandig]

Finally getting around to replacing the fuel pump.

It continues to amaze me that, for a truck so big, everything is such a hassle to work on. All the pieces and parts been removed now, so it's just a matter of replacing with new.

Not sure how well this shows up in pictures, but the fuel pump backing plate has two gaskets. Add that to the gasket that's still glued to the block, and that makes 3.

A total of three gaskets, just for the backing plate alone. I guess we found one of the leaks...

 

[mrandig]

Looks like someone went at this adapter plate, hard. Someone with a screwdriver.

I'm tempted to replace it, as it's gouged up pretty bad. That said, I'm feeling lucky tonight, and sick of trying to source parts, so I may just roll with it and see how it turns out.

I haven't looked at the block yet, as there's another gasket to remove on that side also. Hopefully it's not this beat up.

 

[mrandig]

The new fuel pump is now installed.

I'd be lying if I said it wasn't irritating, but it didn't take too long.

Here's all the parts.


Just for ease of assembly, and keeping everything in place, I use Gasgacinch. It supposedly a sealant, but it really acts more like contact cement.


A little grease on the fuel pump push rod. Fortunately, the cam was in a good position, and I didn't have to crank the engine to seat the rod properly against the pump lever.


I didn't take a lot of pics, as I already wished for three hands, photos would have meant four...

Here's the pump installed. I'll connect the lines later, and then we'll see what happens when we turn the engine over.

 

[mrandig]

The new fuel pump is in and has passed testing.

We've got vacuum on the input side.


We've got fuel flowing on the output side.


That said, despite my best efforts, I can't seem to get the hard line going to the filter to thread correctly.

This is one of those moments where it is probably best to walk away for a bit, and try again later.

 

[Retiredwarhorses]

You need to release all tension on the hard line if you haven‘t already, remove the clamp above on the stud and remove the clamp on the intake manifold.

 

[Milcommoguy]

You need to release all tension on the hard line if you haven‘t already, remove the clamp above on the stud and remove the clamp on the intake manifold.

TRUE, And I might add...get a wrench on the that pump fitting with the green dot (last picture pump hard line block) when tightening up to the final torque. Very easy to twist and distort the metal housing.

What's with the kool-aid fuel, CAMO

 

[mrandig]

TRUE, And I might add...get a wrench on the that pump fitting with the green dot (last picture pump hard line block) when tightening up to the final torque. Very easy to twist and distort the metal housing.

What's with the kool-aid fuel, CAMO View attachment 957590

I had to look the red diesel up also. Assuming this isn't Kool-aid, it may be designated for off-road use only. Assuming it's not Kool-aid.

 

[mrandig]

D'oh.

I removed the first clamp, and that gave me plenty of slack.


Lots of slack, but fighting me still, I think just out of spite. I think it's going to be a case where it all fits together easily at some point, after a ton of frustration, no explanation given.

Just another day. Your sage advice is always welcome.

 

[Milcommoguy]

D'oh.

I removed the first clamp, and that gave me plenty of slack.
View attachment 957592

Lots of slack, but fighting me still, I think just out of spite. I think it's going to be a case where it all fits together easily at some point, after a ton of frustration, no explanation given.

Just another day. Your sage advice is always welcome.

Another tip from the peanut gallery... slide the flare nut back a little and observe the flared end to mate STRAIGHT in and square to the pump flare. If not a slight tweeeek to the line to match it up. Not a bend or kink or heavy preload. Looking to easy in and both mating flares KISS. I know this looks and sound simple... but different pumps, the angle to the dangle only has to be a couple of degrees to be off and the cussing begins, LOL Maybe more loosey clamps.

Key words: Cross thread, Tweek, Preloaded, Bent the sh!x out of it, Band-aid

If it was easy... everyone would have a HumV, CAMO

 

[mrandig]

Key Words: *Censored*

I can't get over how frustrating that was. The tips of my fingers are on fire.

The hardest part, for me at least, was trying to manipulate the top of the line at the intake manifold, while trying to align the bottom, and then trying to tighten everything before it shifted around.


Finally. How many days has it been now?

I know I've had to walk away quite a few times.


We've now got fuel bleeding off at the filter. Almost to the engine...


And just like that, it all fits together easily, after a ton of frustration; no explanation given.

 

[Milcommoguy]

Key Words: *Censored*

I can't get over how frustrating that was. The tips of my fingers are on fire.

The hardest part, for me at least, was trying to manipulate the top of the line at the intake manifold, while trying to align the bottom, and then trying to tighten everything before it shifted around.
View attachment 957694

Finally. How many days has it been now?

I know I've had to walk away quite a few times.
View attachment 957695

We've now got fuel bleeding off at the filter. Almost to the engine...
View attachment 957696

And just like that, it all fits together easily, after a ton of frustration; no explanation given.

And I see (could be a troublesome ???) check valve feeding the fuel canister top housing. Known to stick and cause headaches. Switch out to this fitting. (picture shows could be good with slight leak at purge/bleed screw) Something else to fix, lol.
Get that man a beer, AHaa Tylenol, CAMO

 

[mrandig]

I don't know if I was expecting a parade, confetti canons, or a dancing frog, but hearing the engine fire up after all of this time was almost anti-climactic. And it only took two tries.

I say two tries, as the first time I slipped a power steering hose, resulting in yet another quart of Dex III spilling onto my floor. The correct term should actually be spraying, but the result is the same. That's two full quarts of hydraulic fluid on my garage floor just this month alone. Combine that with everything else that's spilled, I'm going to need a mop and an environmental permit.

Anyways, turns out the gas tank was not full of Kool-Aid. Today we'll top up the fluids, run the motor for 30-40 minutes, and just see what happens. I'm not feeling bold enough for an FCF just yet, but at least I can move it now.

 

[mrandig]

Testing is coming right along.

Here's an action shot. Unsurprisingly, it looks the same when it's not running. Less smoke I suppose.


After 45 minutes of idling, the floor remains relatively clean. It is a M1123, so I didn't expect the floor to be spotless.

On the left (driver side), there's a single drip of red fluid. That's from toping up the power steering fluid, so no worries. On the right (passenger), I see Kool Aid. That new fuel pump had better not be leaking. *Insert Keyword here*


Unfortunately #1, there is a dark oil spot growing under the center of the truck. I suspected previously this was happening, but I was too lazy to fix it - I literally have oil percolating out of the dipstick base.


Unfortunately #2, my passenger floor is wet. IYKYK.

Fun fact: I tried to pressure test the cooling system a few days back and couldn't get a vacuum. At the time, I just figured that I was a dumb ass. Turns out the heater core will need to come out.


So, all things considered, I'm not disappointed. A bit more work to be done, but we're getting closer.

Oh, and coming off hard acceleration, the truck will drop below normal idle and die. I'm assuming this is due to the fuel being older than Chester Arthur, but that's something that will need to be checked out also.

 

[mrandig]

And I see (could be a troublesome ???) check valve feeding the fuel canister top housing. Known to stick and cause headaches. Switch out to this fitting. (picture shows could be good with slight leak at purge/bleed screw) Something else to fix, lol.
View attachment 957697 Get that man a beer, AHaa Tylenol, CAMO

I'll add the check valve to my list of headaches.

The slight leak at the purge/bleed screw was intentional, just so I could see if fuel making its way up from the mechanical pump. It's since been tightened down.

Are we talking about this one?