Finally bought a M37!

[chapmajs]

Threw a new parts counter 12V fuel pump on in place of the original, changed inline fuel filter, runs and drives now. It has a boat fuel tank in the bed, guy I bought it from had the original gas tank but someone had, for whatever reason, cut it in half. Fortunately, the tank straps are still in place.

Just ran it for a minute since I still need to get an oil pressure gauge hooked up. Zero smoke on startup, after doing a loop around the lot there was some burn-off smoke but I'm pretty sure it's from oil on the manifold...I think this truck has literally never started since whoever had it before the guy I bought it from...who'd had it for 10 or so years!

I have the slightest amount of braking at the very bottom of the master cylinder stroke, so probably time for a new MC.

 

[John Mc]

Threw a new parts counter 12V fuel pump on in place of the original, changed inline fuel filter, runs and drives now. It has a boat fuel tank in the bed, guy I bought it from had the original gas tank but someone had, for whatever reason, cut it in half. Fortunately, the tank straps are still in place.

Just ran it for a minute since I still need to get an oil pressure gauge hooked up. Zero smoke on startup, after doing a loop around the lot there was some burn-off smoke but I'm pretty sure it's from oil on the manifold...I think this truck has literally never started since whoever had it before the guy I bought it from...who'd had it for 10 or so years!

I have the slightest amount of braking at the very bottom of the master cylinder stroke, so probably time for a new MC.

Was the new pump rated in the 4-5 PSI range, or did you have to keep the pressure regulator you mentioned earlier in the system?

 

[chapmajs]

Was the new pump rated in the 4-5 PSI range, or did you have to keep the pressure regulator you mentioned earlier in the system?

It's 4-7 PSI so I kept the regulator, which is definitely working. With the clear inline filter, I can see when the float closes and stops the fuel from entering the filter.

 

[John Mc]

That's good. The high end of that pressure range could overcome the carb.

 

[chapmajs]

That's good. The high end of that pressure range could overcome the carb.

Yeah that's been my experience with other generic electric fuel pumps. End up flooding out the bowl vent!

Any chance someone in central VA wants to swing by and help me dial in the timing? Pretty sure it's way late.

 

[chapmajs]

Well nevermind, looks like I *will* be doing a carb rebuild! After sitting with gas in the bowl for a little bit, the float filled up and it floods. Kinda figured that was too good to be true!

I looked into the no gauges issue and think I found the problem:


Nothing's hooked up! I rescind my previous statement about the rewire job being pretty OK. I see a new harness in my mid-term future. I did bench test the dash and everything seems to work, though someone did hook up the high beam indicator as a dash light. Couldn't test the speedometer, there's no cable in the dash and I didn't want to jam something that's not the right size in there.

I sat the dash on the fender and croc clipped it in so I could try and read oil pressure, but no luck. The gauge pegs out when the sender wire is touched to ground, but does not read anything when connected to the sender by the dipstick. I'd guess bad sender...I *hope* bad sender!

 

[glcaines]

Threw a new parts counter 12V fuel pump on in place of the original, changed inline fuel filter, runs and drives now. It has a boat fuel tank in the bed, guy I bought it from had the original gas tank but someone had, for whatever reason, cut it in half. Fortunately, the tank straps are still in place.

If the tank halves are in good shape, you can get the tank welded back together.

 

[chapmajs]

If the tank halves are in good shape, you can get the tank welded back together.

Previous owner said it was very rusty, so I'm planning on getting one of those new stainless tanks. Figure that'll eliminate potential rust issues anyway!

 

[chapmajs]

Wow, it's coming up on a year! Didn't have much time for the M37 over the winter and early spring, but I did finally get some time to wrench on it this week. I made a video for my friend Bill Lewis who'd asked what was going on with it:

Last year, I'd discovered my oil pressure gauge wasn't registering anything, so I stopped engine work until I could plumb in a mechanical gauge and check on it. I had to purchase a temporary mechanical oil pressure gauge for another rush repair job last week, and once it was confirmed I moved it over to the M37, as seen above. It definitely pumps oil, but pressure was low. I assumed the oil was gas killed by the previous owner, since they had the distributor off a tooth and seriously miswired...probably cranked it a ton without ever getting it to fire off!

Today I had time to change the oil. Aired up the tires, started the truck, and drove a few laps around the lot to warm it up. Oil pressure came up some during warm-up, not sure if it was cooking off gas in the oil, freeing up a stuck oil pressure relief, or what. Anyway, when I drained it there was definite old gas stink to the oil, and it was very thin. I don't know what weight was put in there by the previous owner to start with. I went to drain the oil filter housing, there was no filter in it, and the drain plug was hardcore stuck. I removed the filter housing from the engine to try and free it up, and absolutely can't get it out! I have drilled it until I can just start to see the threads and still can't break the remnants out.

I'm pretty sure it had a bunch of water in the bottom of the filter housing at some point. There was a ton of sludge, which I washed out with mineral spirits, and under that there was a *bunch* of bad, deep pitting in the bottom of the housing. The back of the plug was super rusty, probably totally galled into the threads. The pitting is so bad I'm worried it will pinhole at some point, so I'm on the hunt for another Military Junior sized filter housing (current one will take a NAPA 1100 or WIX 51100 filter).

It's time for new soft lines to the filter housing, probably order those, the carb kit, and the timing light adapter from Midwest Military.

Found out that the short stub of hose between the thermostat housing and the valve for the cab heater option is slowly leaking.

 

[chapmajs]

Well, I got it out:



Stupid thing fought me the whole way! I had to file on it with a round file until I could clearly see the peaks of the housing threads, then I was able to dig out just enough of the first thread to get a 1/4 NPT tap started in it. The tap cut the rest out. I couldn't pull it out with pliers like one normally does when drilling out a fastener to thread valley diameter.

I don't know how well the pitting comes out in that image, but it's pretty bad. Maybe 1/16" deep. I tried to zoom in on it to show the detail:



I dunno...dare I run that?

 

[chapmajs]

Bought the carb kit, timing light adapter, new oil filter hoses, a bypass fitting hose, and bypass fitting clamps from Midwest Military.

I think I'm going to run the filter housing with the pitting for the shakedown phase, and then swap it out once I'm ready to be driving the M37 on the road. Bought a brass 1/4" NPT plug for it, will be using Teflon tape on it to both make sure it seals on the chased threads and prevent future sticking.

My filter housing was missing the spring, in addition to having no filter in it, so I'm buying a NOS one from Kaiser Willys.

 

[GopherHill]

Well, I got it out:

View attachment 923160

Stupid thing fought me the whole way! I had to file on it with a round file until I could clearly see the peaks of the housing threads, then I was able to dig out just enough of the first thread to get a 1/4 NPT tap started in it. The tap cut the rest out. I couldn't pull it out with pliers like one normally does when drilling out a fastener to thread valley diameter.

I don't know how well the pitting comes out in that image, but it's pretty bad. Maybe 1/16" deep. I tried to zoom in on it to show the detail:

View attachment 923161

I dunno...dare I run that?

I would try it. It's a bypass filter, not much pressure. If you are a worrier, give it a skim coat of slow setting JB Weld.

 

[chapmajs]

I would try it. It's a bypass filter, not much pressure. If you are a worrier, give it a skim coat of slow setting JB Weld.

Hah, I was thinking about something like that...maybe filling it with solder!

 

[GopherHill]

If the tank halves are in good shape, you can get the tank welded back together.

I would try to fix the original tank. It's a pain to fit something else and have the filler neck and fuel gauge work out.

 

[chapmajs]

I would try to fix the original tank. It's a pain to fit something else and have the filler neck and fuel gauge work out.

I don't have the halves it was cut into, and I doubt the guy I bought it from still has them at this point. I was planning on buying one of the stainless steel ones from Vintage Power Wagons...steep price, but guaranteed not to crud up the fuel system, which has been a recurring problem for equipment and vehicle tanks for me! Gave up on the M38A1 too and bought a repro from Kaiser Willys -- it had a CJ-5 tank in it anyway, with the small diameter filler neck.

I do still have my original mounts and filler neck, fortunately.