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1976 Case MB4/94 (unimog 406)
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Discussion Starter #1
Ok guys, help me out. I have searched "rear axle seal replacement" "rear axle seal leak" etc. Lot's of info ( I see I will need a new wear ring along with the seal), but no how to. I have ordered a manual from Eurotruck, but it's on back order for several weeks.

Any info for the actual procerdure involved would be great. Any info on specialty tools needed, where to buy them etc. Anyone live nearby and wants to help...yea, right!


The patient is a 76 Case and the leak is coming from the inside side of the brake rotor, have not yet pulled the wheel, have to get a jack that is tall enough lol.
tks much, Dan
 

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Unimog Moderator
250GD Wolf
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How bad is it leaking? If its not bad, it might just need the wear ring cleaned up or some gunk got in the seal. When was the oil changed last?

How is the diff fluid?

I know its been posted but I can't find it now :) I'll try to dig up some links for you later, try searching for "Hub leak" or "portal leak" instead of axle.
 

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1970 406 Unimog with 9'2" Boss V-Plow....... 1974 404 Unimog Rock Crawler
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874 Posts
Ok guys, help me out. I have searched "rear axle seal replacement" "rear axle seal leak" etc. Lot's of info ( I see I will need a new wear ring along with the seal)
Why do you assume you will need to replace the wear ring? Contrary to some mis-information I've seen on this forum the correct seal which will fit with your existing wear ring is still available.

Also no special tools are needed, the MB factory shop manual shows a special installation tool for the large axial seal but you can install the new seal without it.

BTW I have an MB4/94 shop manual, in the meantime if no one else chimes in on this I'll try to upload a scan of the seal replacement procedure later today.
 

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1976 Case MB4/94 (unimog 406)
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Discussion Starter #4
Why do you assume you will need to replace the wear ring? Contrary to some mis-information I've seen on this forum the correct seal which will fit with your existing wear ring is still available.
.

You answered your own question lol. I'll search around for the right one, I hadn't bothered because of aforementioned disinformation. Any Idea where to get it? I see lots of 140mm but no 136mm (that's the right one yes?) thanks for the reply.

tkv000, thanks for the pm.
Fluid doesn't look bad, the leak is bad though, steady run, not a drip. I just recently purchased it, so have no idea when maintainance was last performed. I do know the fuel filters were full of what looked like black petroleum jelly, but there where no leaks when I looked at it and the engine oil was not very dirty, though I changed it anyway. It only has 6900 miles and 1000 hours.

I haven't gotten into the axle seal yet, wanted info and parts on hand because she won't fit in garage and don't want to block driveway whilst awaiting the seal.

I need to get a hi lift jack, but tractor supply only carries the 48" and I figure I might as well get the 60". National tire and wheel isn't too far away. :D
 

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Unimog Moderator
250GD Wolf
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Scott at Expedition imports said at one time, he had a whole barrel full of NOS 136mm, use at your own risk of leaking.

See this thread here:

http://www.benzworld.org/forums/unimog/1532751-new-hub-seal-406-a.html

Hi Guys,

This is incorrect information.

Yes, there is a service bulletin out by MB referencing the 140MM wear ring as a replacement for the 136 seal/wear ring. HOWEVER, MB is still offering the 136MM directional seals. I had also been under the impression that the 136 directional seals were no longer available and had been superceeded to the 140 seal and wear ring, until discussions with an MB repair shop in Germany. As I was complaining about the costs of replacing seals when the 136mm wear ring was in excellent shape. The mechanic looked at me like I was an idiot and asked why I would do that instead of just replacing the 136mm seals.

Sure enough, we have been ordering the 136mm seals with no problem from MB.

On a side note if someone has all 136mm seals/wear rings and wants to keep it that way, but has a bad wear ring(s), I have a good supply of NOS 136mm wear rings on stock. A number of dealers, us included, also have VERY good deals on the 4063371551 140mm wear rings as the result of surplus sales a number of years back.

Just food for thought.

Cheers,

Scott Ingham
 

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85' U1300L Holset Turbo VA A/C, 66' Propane 404.1 rock mog, 1975 416 Doka, G500, Volvo C303
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Your seal may still be good! You might have blown the seal out of its seat with a leaking locker seal.
 

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1976 Case MB4/94 (unimog 406)
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Discussion Starter #7 (Edited)
Gonna pick up a hi lift jack sat, then will verify what the deal is..tks all


"Your seal may still be good! You might have blown the seal out of its seat with a leaking locker seal."

That's even worse isn't it?
 

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Non MB 1975 Volvo C304, 1958 Kramer U540, 1959 unimog Westfalia 411
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A small bottle jack on blocks may be better than the handyman/ hi lift unless you rig axle to frame so your not lifting the chassis without the axle. The front of a 406 is almost too heavy for the hi lift IMO or look a Doka TD solution there's a clip and I don't know how to find it. I think I use a 6 ton bottle jack and it works great with a little cribbing.Whoops simul post wasn't trying to reiterate.
 

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85' U1300L Holset Turbo VA A/C, 66' Propane 404.1 rock mog, 1975 416 Doka, G500, Volvo C303
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Simple yet so effective!

 

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Sold .....1987 U1250 Unimog
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I have some really tall stands, lowest position is about 26 inches, rated at 10 tons. I thought about trying the youtube approach but I didn't want to destroy the legs as they dont have a lot of horizontal support on the lower half. anyways I put a 4x6 under the two front tires which gave me just enough room to slide them in, let out the air, and presto... SBU jacked up. I also have used cribage and a 20ton bottle jack. Im with everyone else a high lift is really a joke on a unimog. Used one once to replace a spring on the rear but even then it was scary.
 

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85' U1300L Holset Turbo VA A/C, 66' Propane 404.1 rock mog, 1975 416 Doka, G500, Volvo C303
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Dave, not sure what your stands look like, but horizontal support is not really needed. All the forces generally act along the vertical of the stand. Draw a line from the axle to the part of the base that contacts the ground. This is the direction of pressure until another part of the jack stand foot touches.
 

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1970 406 Unimog with 9'2" Boss V-Plow....... 1974 404 Unimog Rock Crawler
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...I'll search around for the right one, I hadn't bothered because of aforementioned disinformation. Any Idea where to get it? I see lots of 140mm but no 136mm (that's the right one yes?) thanks for the reply.
You can get the 136mm seals <HERE>. Before ordering I would measure the wear ring on your truck first. Never ass-u-me anything regarding parts for Unimogs!
 

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1976 Case MB4/94 (unimog 406)
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Discussion Starter #16
Never ass-u-me anything regarding parts for Unimogs!


Roger that, Sean at Eurotruck already told me that. Gonna dig into it tomorrow, and tks again all.
 

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1976 Case MB4/94 (unimog 406)
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Discussion Starter #17
Well here's the scoop.
Took the hub off, no big deal, just a little labor intensive, Ie tire and wheel, rake caliper etc. ( 8 ton bottle jack and a six ton jack stand). Was some gunk inside the ribs of seal so cleaned it out put it back together.. no leak!

Drove it arond mom's yard a bit, engaged air lockers..no leak. Drove it home about 5 miles...no leak. Got a shower came out and checked it... leaking a bit..sumofagun!!!

Verified its a 136 mm seal so I get to do it all again when the seal comes in, gonna place an order today, need a few other bit's and pieces too.

Thanks again all, I thought I was gettin off easy, should have known better lol
 

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1976 Case MB4/94 (unimog 406)
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Discussion Starter #18
OK, got right and left seal and manual, along with some bits and pieces via ups today. Thank you Eurotruck. Gonna get to it this weekend, time permitting.
Was also having some difficulty with title and registration, I think due to age and vin not matching database etc. Got vin verified by Certified inspection mechanic and viola, I also got my title and registration for my 1976 Mercedes pu truck today, woo hoo!
 

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BenzWorld UNIMOG statesman
Unimog 404.1 Diesel (sold :( )1995 LMTV 1078
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... Was also having some difficulty with title and registration, I think due to age and vin not matching database etc....!
congrats on reg. The vin issue is not uncommon. MB couldn't care less in having Mog's vin pattern match the standard nomenclature / pattern that US title systems use.
 
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