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1961 Swiss Unimog 404
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Discussion Starter #1
I just picked up this Swiss 404 troop carrier that had been sitting for some time. Even though it only has just over 15,000 kilometers on the odometer it has several issues. What follows will be documenting the process of sorting the problems out and getting her ready for the road.
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1961 Swiss Unimog 404
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67 Posts
Discussion Starter #2
After a thorough cleaning to removed a small fortune in acorns and pine needles I set about taking stock... While it does run it puffs black smoke, pops through the carb and backfires. It stumbles badly when you give it gas and has no power.

The choke was extremely hard to manipulate, shortening the overall length of the cable and oiling it solved that issue. Easy one down!

Pulling the plugs confirmed what I've read about unimogs idling rich, all where soot covered and the only standout was the tip on cylinder one (white junk).
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I've probably got fuel and timing issues going on...
 

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1961 Swiss Unimog 404
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Discussion Starter #3
I set the valve clearance this afternoon to start from a baseline. I read removing the valve cover could be a bear but it wasn't too bad after loosening the coolant tank and taking out that little strip of metal above the valve cover on the dash.

I didn't have a crowfoot for the valve adjusters so I made my own poor man's 404 valve tool.
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Worked pretty good, I can't complain!
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I found a few tight exhaust valves but nothing crazy except for cylinder one... Remember that plug with the white junk? Cylinder one was way tight on both the intake and exhaust valves, fixed now.
 

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While your in there, check the rocker arm hold down springs. They have a tendency to crack/break at the bottom hook and in the coil on one or the other side.
 

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1961 Swiss Unimog 404
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Discussion Starter #5
I found a surprise up near the cam timing gear...
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Looks like one of the lower timing chain guides failed. I'll be pulling the pan...
 

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1961 Swiss Unimog 404
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Discussion Starter #7
Today I removed the cooling lines and radiator to get the the front of the engine and those timing rail pins. All the hose connections were weeping and cracked with age so new hoses throughout.
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I pulled the fan assembly off the crank for room to work.
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Tomorrow I'll pull the pan for a cleanout... The rivets holding the rubber to the timing guide are not in the aluminum backing so they must be down in the pan.
I happened to catch the shop light pointing down into the engine bay and thought it made for a cool pic.
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1961 Swiss Unimog 404
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Discussion Starter #8
I pulled the air filter today and cleaned it out, lots of junk captured in the oil and a mud wasp nest... Gross!
The rubber gaskets are cracked with age so I cleaned it and set it aside until my parts order arrives.
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Here's one for the experts.... When I pulled the air filter assembly out the green plate with standoffs was wedged under it. I'm guessing it goes over the intake somehow. Does anyone know the correct way this is installed?
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I don't recall the details, but I believe the intake plate was a Swiss feature to block off the external air flow to the engine - presumably to use warmer engine compartment air. From everything I have heard, it just ends up being a flow restriction, so most people remove it. My Belgian 404 doesn't have it, so I can't tell you what difference it makes.

-John
 

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1961 Swiss Unimog 404
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Discussion Starter #10
I don't recall the details, but I believe the intake plate was a Swiss feature to block off the external air flow to the engine - presumably to use warmer engine compartment air. From everything I have heard, it just ends up being a flow restriction, so most people remove it. My Belgian 404 doesn't have it, so I can't tell you what difference it makes.

-John
Thanks!

Removing it sounds like a plan. This thing had me scratching my head, I found it wedged under the air cleaner. It must have fallen down when a previous owner installed the snorkel and was forgotten.
 

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1961 Swiss Unimog 404
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Discussion Starter #11
More progress today...

Got the new gaskets into the air cleaner and reinstalled it back into the mog.

Also figured out how to adjust the handbrake, it wasn't engaging until almost 12 o'clock (see red on the pic) but I got it down some... Much better now.
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I went through and adjusted the eccentrics on all for corners and that's when I noticed the rear brake lines are squashed on both sides of the axle. I've read this is from shipping... Looks like i'll be making some new brake lines.
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Also got the steering indicator installed, the steering wheel did not want to come off!
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Discussion Starter #12
Not much to report... Been stuck waiting on the post office that lost my parts. Turns out all the timing chain guides had lost the rubber pad or were just about to... Waiting on the upper one, the bottoms are now replaced with NOS parts.
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I wonder how many 404's are running around with the rubber gone off these guides due to age...
 

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1961 Swiss Unimog 404
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Discussion Starter #14 (Edited)
I have always preferred the nylon replacements. Far less issues.
Do they make a nylon replacement for the upper one? I have been unable to locate a nylon 3 hole jobber, just the long and short 2 hole lower ones... I read that the upper one is positioned differently on the 4 and 6 cylinder engines in the cars. Mine was positioned in the head with the pins running through the middle and lower holes.


Edit: I just ordered one from you Scott, part #84 on the timing diagram... That and the rear seal are the last things holding me up. The last seal I ordered turned out to be 8mm also! I ordered another from a seller that specified a 6mm OR 8mm seal so hopefully 3rd time is a charm!
 

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1961 Swiss Unimog 404
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Discussion Starter #15
All sorts of little jobs going on...

Replaced the cleaned oil pan after installing the new timing guides. Got all the supports and such bolted on too.
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Also got the new battery shut off installed.
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Still working on cleaning up the wiring and fuel lines...
 

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1961 Swiss Unimog 404
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Discussion Starter #17
Pulled the distributor for conversation back to points and found the mechanical advance was a rusted up gooey mess, no way the last few owners ever got top performance out of that dizzy, even with going the electronic route. Nothing personal against electronic ignition but I was let down in the past after installing a set in another car and having it strand me. If the wiring in the vehicle is old old old I stick with the points, they will function at a lower voltage than the petronix will.
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Everything cleaned up and moving easily, just need a new fiber washer for the bottom end.
 

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Discussion Starter #18
I was able to pull the top end of the transmission to reseal and clean the shift plate. Getting it back on was a challenge!
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It shifts much better now through the pattern, no hangups like before.
 

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1961 Swiss Unimog 404
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Discussion Starter #19
A very nice forum member sent me some old plug wires and parts from his ignition conversion. I was able to swap the military ends on the plug wires I currently have to hook up to the military coil and cap.
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Discussion Starter #20
Got the rebuilt plug wires and cap on the now installed rebuilt distributor.
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