Two new toys unimog 404

[joeblack5]

Thank you, that looks easy enough. I anticipated a more complex system that uses less muscle power to put the tire in place.
Simpler is better.
Thanks David/

Johan

 

[Ferretboy]

Yes simple....two "J" hooks with some threaded handles....the tire sets on the frame first and then lifted into place....with one hook ready....ive done it by myself...but two lads would make it a breeze.....

 

[joeblack5]

Thanks David.

Did a 50 mile trip today and above 60 kmph the engine occasionally hold back in surges...every second or so.. Maybe sloshing in the tank? At this moment I am running the original fuel pump that I overhauled. I need to take a second look at the fuel system. Would be nice to mount a fuel pressure gauge so that there affirmative knowledge.

Johan

 

[Ferretboy]

Hi Johan.....yes a fuel pressure gauge sounds like a great idea for your electric pump set up......i dont know if your manifolds are the same as mind but the front exhaust manifold bolts to the intake....with a pre heat flap inside controlled with a bi-metal spring...have you checked that?....if its open when its hot.....or stuck open.....that might cause some problems ....dont know the alcohol content of the fuel you use.....????? thats just a thought...im No expert on the subject...sounds great you can take it out for a long ride.....very cool.

 

[joeblack5]

Thanks David, good call, I forgot about that flap and my spring missing. I

Johan

 

[Ferretboy]

Its just one more thing to think about....the exhaust heats up the intake.....the fuel these days with alcohol....or what ever in it might not do well with the heat....but just a thought....love hearing from you and wish i could do half the stuff you do...cheers mate.....David

 

[2manytrucks]

Hello Johan,
I have several 404.1's and nearly all of them with the stock fuel pump will surge at prolonged highway speeds. I have put low pressure electric pumps in line as a booster, which solves the problem, or I've put a newer mechanical pump on which also stops the surging. 404's work on a really low pump pressure. If I remember right, it's around three pounds and they guzzle gas (I usually get a whopping 6 mpg highway), so it doesn't take much to tip the balance in volume. The gas out here on the left coast has as much alcohol as any out there and they still run like a sewing machine on it. If I had to bet on what you're experiencing, it's a fuel delivery issue.

The flap with the thermal spring will cause the engine to stumble hard and backfire through the carb when it's not working right. It's surprising how important that little spring is. The shaft on the flap often seizes on trucks that have been sitting or gets sticky. I use graphite spray on it due to the extreme heat. If it doesn't turn easily, that small thermal spring can't move it through it's full travel.

On the ignition coil, the stock ones do get unusually hot. I'm not sure why, but I've run some here over 23 years now and they still work fine. They are a 12 volt coil which is why the input voltage goes through that round ballast resistor first to step it down from 24 volts. The conversion kits available to switch to a civilian cap/wires/coil and electronic ignition (I've used the petronix kit) in place of points are probably the best single improvement that can be made on these vehicles.

 

[joeblack5]

Thanks 2many,
Hoping it was fuel. Ordered a 24V pump . Will use a external regulator to bring it back to 2.5 -3 psi. The original mechanical fuel pump is still there but I do not know how well it works. I am sure it is just waiting to find a convenient moment to start leaking into the oil pan.. With the price and convenience of an electric pump I will remove it and block the engine off. Then I can get rid of the fuel line running around the whole engine. Also with the current original electric fill pump the start is almost immediately. Nice to know that you turn the key with a full carburetor.
It seems my tank selector is not leaking , also a matter of time , So I will mount two pumps, one for each tank , Like the redundancy in case one pump craps out.

6mpg... hmm better get second tank connected and my fuel gauge working... wonder what the om617 diesel conversion are getting for mpg?

I started to work on a contact less and distributor less electronic ignition system but as usual as long as the old works the priority is low. For now I thru a 12 volt coil in as a spare.

My spring is missing, not sure if the flap is open or closed. The exhaust manifold is cracked on two spots. Not ready to replace or repair at this moment . I bought exhaust tape to wind around it and see if I can keep the heat and noise under control.

Even with all the little "problems" i still love driving this truck.

Johan

 

[joeblack5]

On with my "impovements"

Both of these trucks still have DC Dynamo's and now voltmeter.
When I met with Speedwobble to pick up his old FLU419 frame he gave me a kit he made with USB charger designed for the FLU. Thank you again Mark. Anyhow this set my gray matter in motion and found on ebay a USB charger with a 24 Volt voltmeter and current for the cellphone. So I bought 4 of those from the other side of the world at $9.40/ piece.
From the 4 one was broken and 2 displayed 0.5 Volt low at 28Volt. But..One was OK.. As usual with this stuff, you complain, send some pics, and they refund your money.

I love gauges and a USB charger in the MOG is very useful.
In my dash above the engine there are switches for the missing alarm horn. So I took that switch out, filed the hole a little bigger..... be careful with the expansion tank right behind it.. Then trace out the wiring from the switch. Found the brown and brown / black wire back , disconnected, at the area of the fuse panel. I assume where the horns were located. The brown was already connected to the negative battery so I used the Brown Black and connected it with a 2 Amp fuse to the fuse rail part that is always energized.

 

[joeblack5]

The rubber air inlet hose to the carburator was cracked. It is a tight curve under the dash. i was not happy the way mercedes had routed the inlet pipe nor with the mercedes price of $65.
A the scrap yard I found a VW with a nice air inlet.
I even had a PCV inlet so that the hose from the valve cover can be now a nice short run.
To save some weight and route the inlet so that more of the engine is easier visible I used some 2" PVC 45 elbow. Maybe I will go to ABS since that is black and more temp resistant.
The other ribbed elbow was laying around..even has an air inlet temp probe..the VW hose had two ears on top that I cut with the band saw. Also the pcv stub on the bottom was shorted with the bandsaw. This new hose is a lot more flexible ..

Johan

 

[joeblack5]

Got some nice used broken gauges to repair and play around with from a gent in Bellingham.

Was curious if it was going to fit and look half decent.
Making the hole larger was a slow process ..the old way..to inflict minimal damage to the surroundings.

Cut the back of my old speedometer because it had a non functioning ODO meter..
I liked the older speedometer because it had green dots of fluorescent paint indicating , I assume, max speeds in the gears.

Had to grind flat spots on the bezels to make them fit.. The next step will making a tachometer in the old speedo shell.

 

[joeblack5]

I am driving this Mog regular now and al along it once in a while does not engage 1 high or 3th if you want, all the time.

The gear shifter goes upto 2" from the doghouse. In the last 1/4 to 1/8 of an inch it engages.

of course if it did not engage or jumps out then it takes some time before I can get it back in 1 high because the tranny is still spinning inside.

All gears and clutch seem to work fine 4th high need to go slow especially when it has warmed up. Oil level is good.

My question.. Is my gear lever supposed to go that far forward.?

thank you,
Johan

 

[joeblack5]

Anybody, any insight about third gear lever going that far forward..and jumping out, can the forks have bend inside and not engage completely?

Thanks Johan

 

[Pohl]

Anybody, any insight about third gear lever going that far forward..and jumping out, can the forks have bend inside and not engage completely?

Thanks Johan

"Ought to" could be taken relatively. Many a 404 transmission can exhibit this type of behavior. If all else appears ok, it could be due to:
the doghouse cover itself being "tweaked" and not seating properly; the gearshift lever and force transfer through the vertical pedestal on the transmission top cover thru to the horizontal movement of the shaft its connected to, yada yada. Bent forks are as well a possibility.
The wait time required between the third and fourth gear shift is attributable to the discrepancy between motor and drive train speed. Despite the fact that synchros are present, these trucks like to be double clutched.

 

[joeblack5]

Thank you Pohl,
The dog house is ok all clamps are on and it fits tight al around.

Yes I double clutch and 5 to 6 is no issue for me.
The third gear is a little frustration , sometimes when I am sure that it is in gear but when I start from zero speed at the light it jumps out, then it takes a while before the tranny slows down, so it is frustrating for people behind me, and for me also of course.

trying to find out peoples experience if there is anything else in the lever / selection plate mechanism that can prevent the actual gear to engage properly.

also if the gear just works but is only half engaged I would imagine that over time things would damage or get more damaged.

thank you , Johan

 

[Ferretboy]

Hope the photo is o.k. im seeing 7 3/4 " from the front of the engine cover to the shift knob....

 

[joeblack5]

Wow, that was quick, thank you, oh my , yours looks so ...new.. amazing.

Thanks David,

Johan

 

[Ferretboy]

You are always welcome....hope it is some help....the best to you mate...

 

[2manytrucks]

Hello Johan,
Just to add some other vehicles to David's measurement above, I just checked two 404.1s here and they were 7-5/8" and 8-1/8" so looks like you're right in the average.

When I used to deal with a lot of these, the 404.1's commonly had transmission problems, especially the fire truck versions. I think there are two main reasons.

First, the gearbox in the 404 is largely a carryover from the early first generation models 2010, 401 and 411 which were comparatively tiny (smaller than some golf carts, I have a 401 with a five foot wheelbase, same trans design except non-synchro) and only had 25 max horsepower with a top speed of about 35mph floored, downhill, with a favorable tailwind. The 404.1 has 80-90 horsepower stock and I hit 60mph frequently, albeit on a flat road with that tailwind. So basically the same tranny is hooked up to triple the horsepower going double the speed. The diesels in the small trucks had a red line under 3000 RPM, the 404 easily revs to 6000.

Second, the 404.1 is underpowered with 80-90 horsepower and so you're constantly shifting up/down to maintain any semblance of speed, especially on a highway. To make things worse, a lot of these mogs operated in mountainous parts of Europe like the Alps. When you add it up, a lot of these trannys are just plain worn out. It's telling that the other common problem in the 404 is the clutch being worn or broken.

The good news is there's enough parts for them here in states to build a large fleet.

Jeff

 

[Ferretboy]

When i first got the mog...it ran poorly....after removing and cleaning the carb....about 100 times....i moved on to the ignition......found a mercedes collector not far from me....showed him my distributor and he sold me one from a 1960s car....dont know the year or model....popped it in....had to hook up a vac advance on a port at the base of carb.....she never ran better......ive never went back to find the problem with the original.....plugs....wires....cap....ect....easy and cheaper to do a tune up now....