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Discussion Starter #1
Hey folks,

I just bought a Unimog a few months ago and now that the weather is improving I have gotten to work on her more! The first thing I did was service the portal gear hubs! and I discovered that they were almost empty! Once I filled them back up, and sealed everything back up - I discovered why:



She leaks!! Like - all of them :(

So I ordered up some new seals! -> https://corepartsmb.com/shop/unimogsbu/axles-driveline-sbu/10-bolt-axle-hub-seal/

Is there any other parts I need for this particular service? I found mention of other hub seals and gaskets for Non-SBU mogs.
 

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Hopefully the seals you ordered are not the ones that you linked. If they are you will want to swap them out. You have 6 bolt axles. The axle seal for the 6 bolt axles should be an 016 997 75 47 - They should be 140MM seals. You will also want to check your wear rings to make sure they are not grooved.

Look up the discussion about the seal installation tool and in particular the proper depth to set the new seal.

Cheers,

Scott
 

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Discussion Starter #3
I have 008 997 58 47. Damnit.. Well, I think the parts took so long to get here that likely I can't return them at this point anyway.. Thanks for the part number!
 

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Where to buy?

Any idea on where to buy the below items?

Hopefully the seals you ordered are not the ones that you linked. If they are you will want to swap them out. You have 6 bolt axles. The axle seal for the 6 bolt axles should be an 016 997 75 47 - They should be 140MM seals. You will also want to check your wear rings to make sure they are not grooved.

Look up the discussion about the seal installation tool and in particular the proper depth to set the new seal.

Cheers,

Scott
 

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U1300L
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The guy that answered your post Scott has all that stuff. Go
To his website. Expedition imports. You need to replace the seal
And the metal spacer that goes between the portal gear and the wheel
Hub. Not too hard of a job.
 

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Are these the right ones?

https://expedition-imports.com/0169977547
https://expedition-imports.com/4063371551

If these are the correct ones - how would one know that they were? I'm trying to learn here so bear with me..

I ask because from my understanding the U1300L is a Unimog 435, or SBU type. Are most axle parts between the SBUs and the 40x, 41x and 43x axles interchangeable? As I am trying to service this vehicle in the future figuring out what parts I need is going to be a challenge - the shop manuals do a great job listing all the part numbers for the tools - but not the parts themselves :(

I've seen reference to ID numbers on the axles, so I crawled underneath mine and found these:



But the numbering on my mog doesn't seem to make sense with what's in the listing.
 

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Yes that’s right. The 406/416 are very similar to the 435 and should have the same seals. I’m not sure if the drum brake models were different, but I’m pretty sure that the disc brake models are the same parts.

I’m sure Scott will chime in and confirm that those of the right parts.

As long as your wheels don’t have any play in them associated with the portal gear/bearing just go ahead and replace the seal. But if there is any play you may need to rebuild. It would only be a mater of time until it leaks and fails again.
 

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Take wheel and hub off. Extract old seal measure and or note # on it. Get charge card ready call Scott and away you go.
 

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There is no hard and fast when it comes to the Unimog and parts. There are generalities, and processes to follow when it comes to the parts support. If you know your part numbers, enter them into the search box on our site, and that is a good starting point.

How do you get your part numbers? Parts books, or for later trucks the Electronic parts information systems. If you do not have your part numbers, then you simply start a ticket in the system, supply the Chassis#/axle# and let us do the parts specifications for you.

Your picture is of the axle casting, not much use to us. Axle number is usually a stamped metal mag above the fill plug on the center diff.

In general, Disc Brake 6 lug axles, have quite a few similar parts. However, there are numerous differences. Example, your axle (based upon our phone conversation) is a very early version that does not use the later (and much cheaper surplus) wear rings.

Also just to update this thread there has been quite some discussion on the install of the hub seals. some info from EI here: https://support.expeditionimports.com/hc/en-us/articles/217428777-140MM-Hub-Reduction-Output-Seal-Installation-and-Tool-Cad

Bill Caid has some good stuff here as well: Hubs

Cheers,

Scott
 

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1988 U1300L RW1 Working gears Dual Tanks AC Rigged for Camping Plus: 91 F250 HD 4x4
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Expanding the conversation

I think it relevant to fold a post from Kreitpiel re: Expensive Unimog Tools into this discussion, as per the old adage "you can never do just one thing" (mainstay of the Journal of Unintended Consequences). I am doing this as a cut and paste, so that Kreitpiel's post does not revert to chronological order.

OK, so, I am into making a portal tool, but have a question about some of the dimensions. I am hoping someone (Scott ?) can double check for me. The way I see it, the bearing will sit (locate) on the small lip as per pic 1. However, the bearings I have does not sit as such, with the inner lip of the shell being 148mm. Not 155 as per the drawing. A translation error ? or perhaps a change in bearing dimensions somewhere along the line ?
From the post:

View attachment 2510304


This touches on a multitude of issues, some of which I think I have some useful experience with. Another, longer post by me to follow very shortly.
 

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1988 U1300L RW1 Working gears Dual Tanks AC Rigged for Camping Plus: 91 F250 HD 4x4
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Escapades of the Wild Portal Seal Install Tool

As in all things Mog, there is no one answer, or even a single path to an answer. Full background info is required in all situations. The Background:

When I secured my RW1, from VK Cars, Andy told me that one portal was leaking, and one was weeping. Knowing that I was to take delivery in Galveston and drive 1200 miles home to Denver, he said that the seals (all 4) had to be replaced. He sends work like this to a pair of moonlighting M-B truck/ ag mechanics in the Netherlands who are Mog enthusiasts. He also recommended that they convert to a more modern cassette seal, I believe that originated with the 419. In this seal, the outer diameter press fits to the portal box, and the inner diameter press fits to the wear ring. The seal/ rubbing surface is between the halves, and is rubber on rubber, no relative motion on any metal part of the hub. Gets away from wear issues on the wear ring itself. One issue though is that the wear rings have to be turned down and flame polished/ re-hardened (?). I had the cassette seals installed, all four. Got the truck, and after Googling driving lessons, drove home uneventfully.

Truck in the shop for about 6 weeks, as I installed AC and connected up the dual tanks. Took it out, finally, and switched to 4WD, then diff lock (first time) on our gravel road. Back in the shop, and a couple days later was aghast to see flood of gear lube all over the inner side of the left rear brake disc, shoes, all over the rim, etc. Jacked up, wheel off. Of course the seal has failed completely. Andy on holiday at this juncture, and my calls all over the world were to no avail in figuring out my problem/part installed/ tool to install. When Andy returned from vaca, it turns out that the cassette seal is unique to the 419 in a couple ways, the face of the seal is stepped, which the tool must accommodate, and the M-B tool for the 419 apparently is based on a 60mm wear ring/hub bore, whereas the 435 series (mine) has an 80mm bore. Critical, for establishing concentricity. A number of independent shops in the Netherlands had had issues trying to install by carefully tapping in the seal, and so a machine shop in the Netherlands made a few custom tools for this seal on a 435. All tools spoken for when built. No one in North America knew anything about this adaptation.

Okay. Step Two:

View attachment 2510328

In analyzing the failure, I found about 0.050 inch runout relative to the face of the wear ring. My conclusion was that this created a "swash-plate" action in the seal rubbing surface, in that the relative displacement from inner to outer would go from none (starting point, as pressed) to double that, once per revolution. My guess was that the air pressure from the 4WD found the vulnerability. Concluding that "best response" was to absolutely insure an even insertion, I designed an insertion tool of extreme accuracy. The ole "fool me once...." scenario.The goal was to start the insertion of the seal parallel to the plane of the wear ring, and move it evenly into position, and stop at a positive, even depth.

View attachment 2510326

Got a hand drawing of the custom tool from Andy, which was great EXCEPT THAT the need to dimension the face, to match the seal step, was alluded to, but not provided. Also had to do Google Translate of the notes, to decipher (see penciled in). Got the PDF of the M-B tool from EI website, as a good solid reference. Measured everything I had, including the 3 new cassette seals Andy sent me (warranty), and designed a tool. Another issue with these seals is that the wear ring must be bolted down securely, so the inner diameter is pressured to the final resting place of the wear ring itself when the disc and hub are finally installed.

Here are the components. I did the square stuff on my table saw (must use proper neg rake alum blade, and WD40) and on my mill. Had to take the turnings to a small shop nearby. Guy gave me a real break, only $250 USD cash for that work. Materials from local Alum supplier/ recycler, plus hardware from MacMaster-Carr, set me back about $150 more.

View attachment 2510330

Here is the assembled tool. The outer alum sleeve has it's face cut to match the step in the seal face. That part I had to make a judgment call on, based on averaging face measures of the three new seals I now had. The outer sleeve fits with minimal clearance over the inner sleeve, which is itself a heat shrink fit on the base plate. The tight clearance over the full seal diameter reduces "tilting" to an absolute minimum. The base plate is held to the side gear by the strange 4 bolts. Couldn't use hub bolts, they impinged on the inner sleeve wall, no room, so I used 1/4-28 socket head cap screws (GR10) with slugs of M16 x 1.5 (with ThreadLocker Red) as necked down securing bolts. The base plate has an 80mm boss, for concentricity, and the center threaded rod pulls from the backside of the base plate. An alum block inside the inner sleeve is a base for two shoulder bolts, that position the top press-plate, and prevent any rotation while pressing. Used 1/2 inch fine thread hardened rod, and a thrust bearing to reduce friction while cranking down. The length of the two sleeves are set to provide a pre-calculated insertion depth when the press plate "bottoms out" on the inner sleeve, more or less centering the seal in the available depth. Seal parallel to plane of face of wear ring is guaranteed, to tightest tolerance possible.

View attachment 2510332

Inner sleeve bolted onto the hub, with seal a slip fit over, and ready to add outer sleeve.

View attachment 2510334

Outer sleeve, press plate, bearing, nut and washer installed, ready to press.

View attachment 2510336

Crankin' 'er in. With the thrust bearing, it was virtually effortless.

View attachment 2510338

Outer sleeve, press plate, bearing, nut and washer now removed, seal is set to depth.

View attachment 2510340

Freebie: My brake piston expander.

View attachment 2510342


So, after all that fracas, put everything back together, then checked other rear seal. It measured much less runout, but decided to put the tool on, and seat it both deeper and truly parallel.

Eventually, got all other truck issues sorted, and took off in October (!) for Canyonlands. 1500 miles driven, not a sign of a drip, but then.......

On the hard 60 mile drive out from Tuweep, at speed on a rough gravel road, one front hub dripped a bit (4WD the whole way, smoother ride).

Still 400+ miles to go, so I did. Late in the day, on the highway, two other hubs started to drip, but totally dry on the one I replaced. Next day, finished the trip home, checking portals regularly. Everything held, except for my peace of mind.

Before my latest trip, in April, I pulled both front wheels and brake discs. Right side had tiny drip, look okay, so I pressed it for good measure. Left front was a mess, and checking quantity of lube drained, it had lost significant volume, albeit not dry. Still having two new seals, I pulled this one. To my consternation, the bore in the portal box had significant corrosion and pitting on the bottom arc of the bore. I made a tight cardboard circle protector for the bearing, and 220 gritted the corrosion as best I could, then use Brakleen.

View attachment 2510344

When I set the seal, I first used Permatex Surface Activator and High Temperature Sleeve Retainer on the bottom third of the portal box bore. The goal was to seal the seal to the bore, as I suspected that the leakage was through the pitting of the bore. Did another 970 mile jaunt, including about 180 continuous miles in 4WD, and no drip whatsoever from this hub. Right rear dripped a tiny bit on the way in, while in 4WD, but when I pulled the fill plug, gear lube flowed out on me. Why you always carry waterless hand cleaner. No more drips there, for the duration, but I plan to redo this seal as well; well, just because.

So, unasked for, but still a rousing primer on Why We Love Our Mogs.

If there is interest, my tool drawings are all hand drafted, but I can scan and post, as a general reference as to how I went about this. Modifying for other dimensions/ seals would not be too hard.
 

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1988 U1300L RW1 Working gears Dual Tanks AC Rigged for Camping Plus: 91 F250 HD 4x4
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Yes, I think it would be great to see some of your tool drawings.

Michael
Gladly. First the disclaimers:

I am an old-school hand drafter for about 55 years now. My drafting is for myself, and I take a lot of shortcuts, even if seemingly using conventions.

I scanned to JPEG, so I could edit somewhat, as the scans to PDF do not print well.


The originals are full size, except the detail of face is 4x: all are accurately drawn to scale, to insure all would come together properly. The center block and octagonal 1/2 inch thick press plate were made by me from a couple of notes, but it is easy to derive the pieces involved.
For simplicity I use CNC dimensioning often, but then don't bother with +/-.


Portal Insert Tool

This is a composite set of sections. Left half for the detail of the 4 plate attachment bolts. Right half is for the details of connections to the center block. The block is to give solid support to the center rod and 2 shoulder bolts, eliminating torque and bending. The block is 1 1/2" thick, and top and bottom machined flat. The lower portion of the rod bore is threaded. The bore in the bottom plate is thru-hole: the bottom nut tightens the block to the bottom plate. The socket head cap screws are 1/4-28 x 2 3/4". Shoulder bolts are 1/2" dia. with 3/8-16 NC threads as are the flat head socket heads to attach the block (and prevent rotation). I use my simplified version of simplified thread representation. The sleeve is drawn retracted, and seal is shown fully inserted.

Black=Aluminum tool parts Red=threaded Blue=hub and wear ring

Portal Insert Tool.jpg

Detail of Face of Outer Sleeve

This is the part I had to make executive decisions on re: cut to match the seals I had. The inner/ outer rings of the seal do have some relative motion, and I went for an offset that gently pushed them tighter. Seems to have been a good plan.

Red=outer sleeve (face) Blue=seal black=portal box/ wear ring/ inner sleeve/ bottom plate

FaceDetail_OuterSleeve.jpg

Inner Sleeve and Bottom Plate

In the section left is for the 4) 1/4" cap screws and right is for the 2) 3/8" FH socket head. I did the holes on the mill on a square plate: the machine shop cut the diameters on the plate after, using my center. The shrink fit is fine, because the tension is through the rod from the bottom of the base plate, which is 4-bolted to the side gear through the wear ring. The inner sleeve is subject only to compression, during the final squeeze; it can't go anywhere. It does establish concentricity, then serves to keep the outer sleeve on axis, thus pressing the seal in evenly, and is the "stop" for the press depth.
v= finished surface

Inner_Sleeve.jpg

Outer Sleeve and M16 Slugs

Only drwg in the bunch that is almost self-explanatory. The notes to "VERIFY" are to check that the inside step JUST slip fits over the wear ring, and that the ID is the CLOSEST possible slip fit to the actual inner sleeve( which was cut first), thus keeping "tilt" to a minimum.

Outer_Sleeve.jpg


Photo that didn't make the cut on the earlier post. This is the seal sitting properly on the outer sleeve. The "tops" of the sleeves are flush, on the table, which is equivalent to the inserted condition.

P8300572.jpg

Finally, if anyone out there cares to create CAD drawings, I'd be more than happy to assist (I don't have the software, and couldn't use it anyway). The concepts here can be invoked for any hub/ seal combo.
 
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