Two new toys unimog 404

joeblack5

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IMG_20200409_112304_333.jpgSo I was in need of a truck that can get me thru some swampy area. Found one but the PO had two for sale . so well... Two it was.
They came from California and sat in the desert for 15+years.
Sofar I have removed the sparkplugs and dumped a couple of teaspoons mystery marvel oil in each cylinder.. Then I put them in 6 gear and raised one rear wheel. With a crowbar they both came loose.
Got some batteries and tried the starter with plugs out . On starter the oil pressure gets up to 2-1/2.. The closed cab fire trucks ignition wires are sparking. Did a compression test on both and all 6 show compression although all over the place.

So now I am starting on the fuel system and I find that the fire truck has an in tank electric fuel pump.. I have a factory manual but there is no mention of this pump.
Found some posts about this pump but no details.. Does anybody has a fuel diagram with a factory electric fuel pump?

Thank you.
JohanIMG_20200409_112304_333.jpg
 

joeblack5

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Factory manual, or TM?
Hi Guy, hoping you would respond,

I have the UKD 40 402 2132 Werkstatt- Handbuch 404S.

I have read people writing about a factory fuel pump to avoid vapor lock. But found no details. The carb has two hard lines to the banjo bolt. I assume there is a pressure regulator inside the banjo bolt like the mercedes diesels have on the IP??

The mechanical fuel pump on the M180 is there also,, maybe use the electrical pump for a couple of seconds to flush /cool the fuel lines and then the mechanical pump takes over?
Just downloaded some military TM's from GamaGoat but no mention of electric fuel pumps ( I can read German since I am original Dutch)

The top cover on the fuel pump was loose and I could see the electric motor, commutator and brushes, All looks in good shape. But pump is electrically disconnected.

Thank you,
Johan
 

Guyfang

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Johan,

I do not remember an electric fuel pump on the Military CEE truck. I didn't work much on them, but do not remember one. Do you have the Army TM's for the CEE truck? There are posted in the forum. Also, try and contact Migginsbros here in the forum. He has much more info on the
MOOG.
 

joeblack5

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Thank you, here is a picture. Inside the housing is an electric motor.. It seems there is a return line to the front tank as well.IMG_20200416_181652_735.jpg this is a 404 415 ??? 040-608
More studying to do.
Johan
 

joeblack5

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Took the tank out . Black liquid tar / varnish inside. Removed the pump. It was seized up.
Tried to add some diesel and nuts and bolts but the tar was to thick and sticky. So with all covers of I took it to a carwash with hot soap pressure cleaner. Came out nice. Some pics if pump and carb connection. A fuel diagram if anybody has it would be nice.IMG_20200417_111022_291.jpgIMG_20200417_131612_688.jpgIMG_20200417_133347_613.jpg
 

joeblack5

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For documentation purposes only..
Tank after cleaning, pretty nice, no corrosion at all.. Zenith electric Fuel pump parts. Detail commutator and brush. Had to solder on the strainer to close a damage..there was a second impeller or so on the same shaft. It is sofar desintegrated that i left if of..Sofar i have not found any info on this pump.IMG_20200419_100632_849.jpgIMG_20200419_100524_601.jpgIMG_20200419_103002_282.jpg
 

joeblack5

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Put the tank back on and filled with 5 gallon of gas. Hooked all up and connected the pump to a separate 12 volt battery.. Pump is pretty loud...So I learned that the front is the reserve tank and that the tank selector has to be in reserve... Next was the fuel strainer in front of the mechanical pump.. It opened up OK but the strainer itself was loose. Tinned the edges and soldered it back around the core.. Next was a overflowing carb.. So took it of and it turned out that the seal under jet cover was dry cracked. Took a thick o- ring. At the same time I cleaned the carb , jets, small orifices . The gasket was in bad shape. Got pretty thick gasket / rubber paper and made two new ones.
IMG_20200422_224618_612.jpg
Well it was worth it. Success.. Second crack it fired up and idled pretty smooth.. But a high screech... Water pump stuck..
 

joeblack5

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Well success was a little premature... These units were sitting in the California desert for 10 to 15 years. Oil in this one seemed to be clean as in just changed, i guess 10 years ago. There was no coolant. Yesterday i just ran it for 30 seconds on idle and unfortunately did not check for water in the oil since there was not coolant anywhere. Today I filled up clean water to flush and had a bit of white smoke for about 3 minutes , then it was clean, maybe mystery marvel oil?? Anyhow the oil is for sure brown emulsion at this moment. Drained all the oil and left the water in and see if tomorrow there is water in the oil pan.

Then the brakes , oh yeah,, no fluid either, replaced the des-integrated brake fluid container. Filled up oil , no oil to the brakes.. cut the hoses and indeed , swollen up. So i ordered a new hose kit and will replace the steel sections as well. Before that comes in I can clean the calipers and see how bad the coolant in the oil is.

tbc

Johan
 

joeblack5

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Further experiments. no visible water came out of after I removed the oil drain plug . I had drained the oil out yesterday but left the cooling water in the expansion tank. Some thick honey brown sludge dripped out the oil drain,
Decided to take the oil filter out as well and there was more brown sludge.. Hope it did its job.. I am planning on running cheap 15W40 diesel motor oil from walmart with a new oil filter in the hope that the extra cleaning / anti sludge will help clean the engine out.
Any suggestions?
I also removed the sparkplugs and cranked the engine to see if there was any water in the cylinders. Did not notice any.
So far so good.
Anybody experience with 10 year old motor oil turning to sludge in a desert environment?

Then I moved on to the older 1958 404 .114.

Reinstalled the distributer and sparkplugs and reinstalled the " cleaned carburetor" This truck had the OEM fuel pump removed and replaced by an aftermarket electric fuel pump. That fuel pump is a van pump and was stuck with old tar gas.
This fuel system is already botched up. The problems with to much fuel pressure are concerning. I think I am going to copy the fuel system of the other truck.. That is Tee of the fuel line just before the carb and let the extra fuel flow back in the tank... Also better for vapor lock.
Took the fuel tank of to try and clean it out again.

Anyhow I could not resist the urge to try to start and used some starter spray. It fired up. These little victories keep one motivated. I am all for instant gratification....So on to the electric fuel pump.
tbc

Johan
 

Guyfang

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Further experiments. no visible water came out of after I removed the oil drain plug . I had drained the oil out yesterday but left the cooling water in the expansion tank. Some thick honey brown sludge dripped out the oil drain,
Decided to take the oil filter out as well and there was more brown sludge.. Hope it did its job.. I am planning on running cheap 15W40 diesel motor oil from walmart with a new oil filter in the hope that the extra cleaning / anti sludge will help clean the engine out.
Any suggestions? (I am a generator guy, but in this situation, I would take some ATF, and fill the engine up with it, put in a new cheap oil filter and run it for 1/2 hour. Then drain it, and change the filter. This is what we did, and the instruction came from CECOM Command, to help with this sort of thing. And we normally got the oil pressure back up a few PSI. Does this engine has an oil cooler? One that is cooled by running oil through a housing that had passages were the engine coolent also run through? When ever we had water in the oil, and check the radiator neck also, the problem often there. The oil cooler.)
I also removed the sparkplugs and cranked the engine to see if there was any water in the cylinders. Did not notice any.
So far so good.
Anybody experience with 10 year old motor oil turning to sludge in a desert environment?

Then I moved on to the older 1958 404 .114.

Reinstalled the distributer and sparkplugs and reinstalled the " cleaned carburetor" This truck had the OEM fuel pump removed and replaced by an aftermarket electric fuel pump. That fuel pump is a van pump and was stuck with old tar gas.
This fuel system is already botched up. The problems with to much fuel pressure are concerning. I think I am going to copy the fuel system of the other truck.. That is Tee of the fuel line just before the carb and let the extra fuel flow back in the tank... Also better for vapor lock.
Took the fuel tank of to try and clean it out again.

Anyhow I could not resist the urge to try to start and used some starter spray. It fired up. These little victories keep one motivated. I am all for instant gratification....So on to the electric fuel pump.
tbc

Johan
Open to see what I wrote.
 

Karl kostman

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Joeblack congrats on joining the UNIMOG CLUB! There are a few of us odd balls here but always remember WE have extremely good taste in REAL trucks! I had a 404 for a couple years and my truck did not have that electric fuel pump on it at all, in fact I have never seen a setup like that? As far a engine oil and lubricants of all types sitting in the desert can definitely not be doing the truck any favors. Obviously your are changing the engine oil in both engines, dont care how it looks its got to GO! I would also highly recommend you pull the wheels and hubs and take a good look at the wheel bearings. What happens here is that in HOT environments the grease will melt out of the bearings and you will have exposed metal and its going to likely rust, bad on bearings. This will also go the the axle portals, its easier to take them apart now and find all is good then to wait and then find all was not so good when you have a failure, just in case you havent noticed yet some parts can get expensive. As far as you fuel system goes there is two ways to handle this, one is to piecemeal it together and just keep fixing it when you get a new dose of tar that decides to let loose, or you can do it once and do it right? I would have both fuel tanks cleaned out very well and relined if needed, you can really tell until they are clean then I would pull all my fuel line off and run wire through it with some kind of gumout cleaner and lots of compressed air until its completely clean. This is also the time to re-seal fittings etc. You are going to need either a different fuel pump or you going to need a regulator on it, with the carb on that truck (it needs to be rebuilt also) you can safely run around 3.5 to 4.5 pounds of fuel pressure without a problem and that is AFTER you rebuild the carb! You have a very great piece of engineering history with the 404 they are great trucks, they will never win any kind of race but they will sure go through and over a lot just do it slowly! Good luck and congrats! Of course welcome to the club!!
Karl
 

joeblack5

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Thanks Guyfang, Yes that ATF would have been better. was at Tractor Supply and they had 2.5 gallon 15w40 diesel motor oil on special for cheap. So that was my choice.
Cleaned the gunk out of the oil filter housing and installed a new filter. Pre filled with a bit of 10w30 before install and then cranked with plugs out tille I had oil pressure.Put plugs in and started it up.. No white or smoke at all. Oil pressure full scale and 2-1/4 after 1/2 hour.
A little valve noise and some backfire coming from low idle. Temp gauge broken ... and leaking coolant around temp. bulb.
es
Clutch engages and dis engages. Drove it forward and backwards a coupe of feet but had only a parking brake....
Next step will be another compression test and valve adjustment and see if I have coolant in the oil.

The 58 mog was less lucky. Set up a test with a fuel return line and electric pump out of a 2.5 gallon jerry can. But the carb was still leaking.
It fired on ether but did not stay running on the carb,. Maybe I will use the carb from the running unimog for testing .


Hi Karl, thanks for the hints. Tomorrow i will start cleaning out the tank from the 58 Mog and will take another look at ethe carburetor.

tbc,

Johan
 

joeblack5

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Tore the 58 unimog carburator apart. Fuel level was very high, so I think i just was so rich that it could not run at all? It did fire on ether and even had a little fire ball come out of the carb, may be liquid gas in the manifold?

Either way, checked the fuel level and it seemed high to my inexperienced eye. Could not find an issue with the float valve but while I was wondering what was going wrong I suddenly realized that for my home made gasket I had used 1MM thick material and the old on was 0.25 MM.
A little Aaha moment came up.. guestimated the float arm length and calculated that my 0.75 MM thicker gasket must have resulted in 3 MM about 1/8" higher gas level. Now is that enough enrichment for the motor not to run? Seems not, but I learned something. Will see if I can rig up a fuel bowl level tube and see where it all goes wrong and try again tomorrow.

tbc
Johan
 

joeblack5

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Well, the kids were annoying so I thought better cool of in the shop....in the manuals about this zenith 32 carburetor I had seen a picture of the fuel level inside the carb.. The thread is an amazing uncommon M7x1 mm .. My cheap harbor freight set had the tap and die. In the pile of brass coupling I found a piece usable for modification. At least this will take the guess work out of it.IMG_20200426_204054_391.jpg
 

tennmogger

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Johan, I have read your thread and see several unanswered questions. Concerning the added electric fuel pump, yes, this is common modification to do two things; 1) boost pressure to the carb to overcome vapor locking as you suspected, and 2) prime the carb after sitting a long time or even if shut down recently. The gas can boil out of the carb in a surprisingly short time. Then the electric can be shut off and the mechanical pump takes over.

In the hardcab 404, having two banjos on the carb is normal. One comes from the mechanical fuel pump, and the other from the electric pump, of course. This works because neither pump will pass fuel in the opposite direction. I use a similar system with an electric pump but my 'dual banjo' is located at the output of the mechanical pump.

If you add an electric pump, on the rear fuel tank there is an unused port in the bottom of the tank, left front corner. A banjo can be added there and fuel supplied to an electric pump down low (through a filter). This is the ultimate cure for vapor locking. From the added pump my fuel line runs to the output of the mechanical pup, putting the two pumps in parallel just like your hard cab.

Engine Oil: The engines will run fine on 15W40 as you plan, however, in cold weather you might want to go to a synthetic. I run Walmart full synthetic 10W30 and that really helps the engine start in cold weather. The synthetic lets the engine run to high rpm easier too. These 404's are high rev'ing systems, and 5000 rpm is not uncommon.

I know you asked more but I don't remember what.

[edit: those were Kelly Minnick's trucks weren't they!! Glad to see them resurrected]

Bob
 
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2manytrucks

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Johan,
I just saw this post and I have a '65 404.1 TLF-8 with that same exact electric pump on the front tank as it came from Germany. Do you still need a diagram? I don't have one, but I can sketch it out.

Strange coincidence, I live about 75 minutes from where those trucks were for sale in California.

Jeff
 
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