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Discussion Starter #1
Hello everyone!
So I'm a proud owner of my first Unimog, dream truck for many years.
The purpose of this post is to, share my story/frustration, help me find out just what happened and to point me in the right direction to perform a clutch job. I do have the repair manuals however.

After purchase, i drove it home a hilly 250km without any issues. The next day I took it for a 30min light offroad drive. On the way home I pressed in the clutch to downshift into 3rd, I had a little bit of trouble finding 3rd. I was pushing the gear leaver a little harder than I normally would and I felt a snap and my clutch pedal was to the floor without any resistance. I was able to limp home 2km slowly in 3rd. Drove and felt normal, just didn't touch the gear leaver or clutch.
The 404 had a new 500km old clutch, old pressure plate. The engine was replaced old/new also.
The clutch looks to be a puck style and installed in the not advised orientation. However the repercussions (the fingers being able to strike the spring barrels of the clutch plate when miss adjusted), looks to not have happened.
When I opened up the view port on the bell housing, I discovered that two of the three release bearing springs where not attached... Pictured.
And that the clutch had a material (most likely clutch friction material) lodged between the clutch and the pressure plate. Two pictures of this.
I can't see the riveted ring of the 4th picture in pictures 2 and 3.
Anyway needless to say I need a new clutch. Just wanted to share my story and see if this has happened to anyone else.
I will update this post with pics as I get into it.
Any input of how this could have happened would be appreciated.
What are people's thoughts on the puck/ceramic vs the organic clutch preferences?
I plan to replace the clutch and pressure plate as per the Mercedes Unimog book. They instruct (basically) to free the engine, remove radiator and fan, free the bell housing from the engine then move engine against grill. This should give enough room to get to the clutch. Is this method recommend?
Other than the clutch kit and coolant what else would you suggest to replace?
Thanks everyone!


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Did you by chance push in the clutch in low gear and let the truck roll down a hill and pick up any speed?
 

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Discussion Starter #3
Hey.
No, I don't tend to ride the clutch like that. I prefer not to rely on the brakes for the majority of deceleration or to maintain speed. I don't think I done anything incorrect in the operation of the drive.
Thanks DokaTD.
 

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I have done two clutch replacements now but both with the engine out so not exactly apples to apples. I hear it can be done engine in but it’s going to be pretty tight in there. Personally, if I were gonna do it, I would also replace the throw out bearing and maybe even the pilot bearing depending on how it looks/feels just to be sure. It’s a PIA to get to it all so much more cost effective to do it all while your in there. As for puck vs disk, I have used the puck the last two times and have no complaints. Is yours a hard or soft cab? Reason I ask is it will probably be much easier to position an engine lift on a soft cab to support and align the motor.
 

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Discussion Starter #5
Thanks TMogger.
Yes, it's a Swiss soft top. Shop Manual requests to remove the windshield and shows a long hoist attachment bar that runs the length of the removed value cover with eyelets at the ends. It appears to be bolted to the block with the valve cover bolts. Neat method. Just need to fabricate one. I plan to get the four piece clutch set.
Thanks for the input TMogger!
 

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Here are some 404 clutch photos. Probably nothing too helpful, but I'll post them in case there is something that might help the orientation of things, etc.

Some show carnage, some just t the OEM pieces.
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You didn't do anything wrong. I think you had a failure that many of us had with a bad production run of pressure plates. One of the pivot points under one of the three pressure plate actuating levers has collapsed. That drops the pressure on that arm, the pressure plate does not disengage on that 'corner', and the clutch drags as it did with you. You can't shift gears. You push a little harder (the normal thing to do) and the springs get into the clutch disc. Your pictures show that. Lots of bad things follow.

It is easier to change the clutch components by sliding the engine forward. Sorry you have to go through that.

I have some pictures of another bad PP but no time at the moment to figure out how to send them (or to delete the original post...sorry for the clutter.) There's definitely a learning curve on this new posting system.

Bob



Hello everyone!
So I'm a proud owner of my first Unimog, dream truck for many years.
The purpose of this post is to, share my story/frustration, help me find out just what happened and to point me in the right direction to perform a clutch job. I do have the repair manuals however.

After purchase, i drove it home a hilly 250km without any issues. The next day I took it for a 30min light offroad drive. On the way home I pressed in the clutch to downshift into 3rd, I had a little bit of trouble finding 3rd. I was pushing the gear leaver a little harder than I normally would and I felt a snap and my clutch pedal was to the floor without any resistance. I was able to limp home 2km slowly in 3rd. Drove and felt normal, just didn't touch the gear leaver or clutch.
The 404 had a new 500km old clutch, old pressure plate. The engine was replaced old/new also.
The clutch looks to be a puck style and installed in the not advised orientation. However the repercussions (the fingers being able to strike the spring barrels of the clutch plate when miss adjusted), looks to not have happened.
When I opened up the view port on the bell housing, I discovered that two of the three release bearing springs where not attached... Pictured.
And that the clutch had a material (most likely clutch friction material) lodged between the clutch and the pressure plate. Two pictures of this.
I can't see the riveted ring of the 4th picture in pictures 2 and 3.
Anyway needless to say I need a new clutch. Just wanted to share my story and see if this has happened to anyone else.
I will update this post with pics as I get into it.
Any input of how this could have happened would be appreciated.
What are people's thoughts on the puck/ceramic vs the organic clutch preferences?
I plan to replace the clutch and pressure plate as per the Mercedes Unimog book. They instruct (basically) to free the engine, remove radiator and fan, free the bell housing from the engine then move engine against grill. This should give enough room to get to the clutch. Is this method recommend?
Other than the clutch kit and coolant what else would you suggest to replace?
Thanks everyone!


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Discussion Starter #10
Thanks Bob.
I will check out those pivot points once I'm in there. When I opened the bell housing port, I had two of the three finger springs detached and the contact points from the fingers to the TOB where not aligned in the notch. As long as it doesn't happen again. I will update when I'm in the bell housing. I do plan the method of shifting the engine forward. I'd love to see those pics if you or anybody finds then.
Thanks Bob.
 

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Hi Truktor, that's a great set of pictures. Much better than the pictures I had and can't find now.

Thanks
 

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Discussion Starter #15
Wow, Truktor. Nice pics! Thanks.
I'm feeling fairly confident to perform the job. I'm however having trouble finding recommended engine lifting points. I want to have everything down packed before I drive into the job. I have a forklift as my hoist. Just need help with safe chain mounting points on the engine. Thanks.
 

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Here are some shots of improvised 404 engine removal / positioning rigs.

They are avoiding the cylinder head bolts, for whatever reason. The bodies are also removed, so there isn't a direct relationship to your situation - just some alternative approaches.

The rig with the Suzuki...well, you do get the driver throwing the Goat horns....

Again with the duplicating / multiplying posts. Odd.
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Some clutch / TO bearing stuff, and a couple of Vintage shots of the Engine / Trans assembly for entertainment
purposes.
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TRUKTOR
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