Supposed Navy Clark Clarktor-6 Tug/Tractor

A few years ago I bought a Clark "Clarktor-6" industrial tractor (pictures attached). The guy I bought it from got it surplussed from one of the local VA (Veteran's Association, but also in Virginia) facilities, where it was used as part of the grounds maintenance equipment. He'd said, but I have not confirmed, that it was used on an aircraft carrier during WW2. It's one of the "lighter" setups, with single rear wheels, so I guess that'd make it a MILL-30. Engine is a flathead Chrysler, originally it'd have been the industrial six, but it's been swapped with one out of a 1956 Plymouth, so that's not a lot of help in figuring out its history!

I got the engine to fire off earlier this year, previous owner said he hadn't run it in at least 10 years. Needed the usual points cleanup, the starter solenoid was stuck and wouldn't contact (and then stuck in contact!), Bendix gear needed oil as it wouldn't pop out, etc. Here's a short video of it running on saw gas squirted down the carb:


The carb was of course totally crudded up. Ordered a complete rebuild kit from Mike's, still need to boil it out and rebuild.

There’s a really great group on these tugs on Facebook. The admin has most of the original build cards for clarktors. If you’re able to read the serial number on the dash plate above the gauges, it’s pretty likely he can show you the build card and where it was originally shipped to from the factory.

I have heard that everyone moved to Facebook from the old Yahoo Groups page. I'm not on Facebook though. Might see if my wife minds me using her account.

Good looking tug! I had a MIL-40 when I was a teenager but stupidly scrapped it.

Turns out my facebook login from college still works! I'm on the Clarktor group now and have posted my data plates, as they are. Figured I'd post them here too:



Number on the left is 84629 with a triangular symbol after it. On the right appears to be T-925.

If you’ve found the machine serial number contact your local Clark parts dealer, they maybe able to get you the original build sheet and parts manual
They made me this one for free about 20 years ago, after I stopped in for some simple parts.
Parts where very reasonable as well.
Not as old as your machine, but still old enough to prove they started a very good library at some point.

There's a guy on the Facebook group who works/worked for Clark and has access to all of the original build sheets, engineering drawings, etc. He used to be on the Yahoo group, before Yahoo shut all of that down.

So, it's been a minute, but I finally got some work done on the Clarktor end of this winter. I pulled the bad "passenger side" steer tire and found a busted off bolt:



I'd pulled the carb after the above "it lives!" video, and when I opened it, I found this wonderful mess:



I cleaned everything, reslotted the chewed up screws with my Starrett screw slotter, and put in a full kit from Mike's Carb Shop. It's much more presentable now:



It was originally bolted to the manifold with a wrong-length stud and a regular hex bolt, and was super annoying to remove under that short hood. I bought these studs off McMaster-Carr:



They are meant for CNC machining surfaces that are full of threaded holes for securing work. The end that goes in the manifold above is threaded with a friction fit thread to keep it from backing out -- you have to install them with a double nut arrangement, but once they're in, they don't back out when you take the carb off. Very handy stuff! They are 18-8 stainless, so make sure to use copper anti-seize compound!

I pulled the blown tire off the rim, which was a real fight...ended up using the Sawzall on the tire. I cleaned the rims up a little and wanted to paint them to stop further rusting and make tire installation easier. I will probably have them sandblasted and powder coated at some point. Someone welded in the bolts that hold the two halves of the split rim together:



Not sure if that's a factory thing, or something done in the field.

I decided to try a new trick to get the broken bolt out: I slotted it with my Starrett screw slotter and turned it into a giant grub screw. Then I tried to blast it out with the impact gun and a 3/8" wide slotted bit (sometimes called a drag link blade). That didn't work and split half the end off. I'm pretty sure someone cross-threaded the bolt and then tried to force it, which is what broke it off. It was a nasty thing to get out. I drilled it out and crept up on the final diameter 1/64" at a time. I couldn't get the thread leftovers out with a punch and pliers, so I cut them out with a 1/2-13 tap and a ton of Tap Magic cutting fluid! It did work:



The first couple of threads were just about pulled out of the casting, but there was plenty of meat left inside.

I ordered tubes with too-short valve stems: the blown one had a totally wrong straight stem, and I measured the other side and used that length to order...before realizing the two wheels are different on my Clarktor! The valve stem barely reaches the edge of the rim:



Fortunately, there's a fix:



...tire valve extenders! You can get these at most auto parts stores, the ones above are 1 1/4" long. They operate with the Schrader valve in the inner tube's stem, so you don't have to pull the valve core to use them, which also means you can unscrew them when you're done. I did remove the one I used, so it won't get broken off. I mounted the tire and aired it up to 50 PSI:



I ordered some NSN'ed deep lug milsurp tires, and I think they look a lot better on the tug than the random probably trailer tires that were on there -- in addition to not being beat, of course! I ordered tubes and flaps off Amazon, 6.90 x 9 is the same as 6 x 9. Definitely want flaps with split rims. The blown out tire/tube that was on there didn't have one.

While I had the jack out there, I lifted the rear end and confirmed the "driver's side" rear wheel is stuck. I think the brakes were set too tight and it rusted to the drum. The "passenger side" rear wheel turns freely, but I can feel brake drag.

Today, I had a minute to gas it up and try to drive it:


It drives! The stuck brake came loose when I let the clutch out at idle. Shockingly, it seems to have working service brakes! I can't tell how decent they are as I still don't have a fuel tank on it and have been running on a carb bowl full at a time. The pedal is very hard though, which it should be on unboosted hydraulic brakes. I drove it over to join some of the other stuff at the eastern fenceline:

Hooked up a temporary tank off a single-cylinder engine and ran the tug some today:


I drove it around the lot at the building enough to warm it up, then drained the oil. Totally black of course. It did have an oil filter in it, a FRAM CH236APL, but it was in upside-down! Ordered a new oil filter, a new air breather filter, and some Rotella 15W-40 from NAPA. Filter will be in tomorrow.

Either the water pump or generator bearings don't sound great. Planning on sending the generator off for 12V conversion (I believe it's a 6V still) anyway. Transmission didn't want to shift into second or third gear, a little persuasion with an engineer's hammer got it into second, feels like it wants to go into third but isn't aligned -- I did the "adjusting" while the oil was draining, so haven't tried with the engine running.

I have the Clarktor running on a temporary gravity feed tank off some single-cylinder engine. I placed it on top of the hood to see if that was sufficient. It runs, but stumbles under load if you give it too much pedal. Pretty sure it's not getting enough fuel with the gravity feed. It will probably be worse with the actual Clark fuel tank, since it's slightly lower.

I was going to hook up the engine-driven fuel pump and try it, but it leaks bad. So, now we're up against the eternal old stuff question: do I run an electric fuel pump that will invariably fail on me, or do I run a remanufactured fuel pump that might leak gasoline into the crankcase one day?