leaks and lockers

[E-steban]

Building this house has been kicking my butt. Just as soon as I seal the garage floors with some methacrylate sealer it will be time to take my 406 apart. My front lockers do not work and I have gear oil leaks on both front and rear right side wheels. Before I get started I wanted to ask a couple questions to the mogwise ones.



Here are the leaks as seen from the outside of the front and rear wheels:








The rear wheel has no leakage on the inside.



The front wheel blew oil all over the inside the other day when I engaged the lockers. Here is a photo of the inside of the front right wheel. Oil is sprayed all over the place. (I washed wheel with hose just prior to this shot) The oile seems to be coming from the hub/spindle seal in the center inside of the wheel.

Would the pressure from bad locker seals cause this oil to blow ?
What parts will I need to repair these front and rear wheel leaks ?





These are the locker seals I bought. They are kind of square cross section. Do they look correct ?




What side do I dissassemble (driver or passenger) on the front of my Case to get at the locker mechanism in order to replace the seal ?

Any other hints or tips before I start would be greatly appreciated.

Thanks a MILLION for your help, Steve in Golden, CO



PS - Here is a photo of the house thus far.



garage side before slate and stucco

[Mogasaurus]

Steve - the house is looking great - certainly a change from when I saw it this summer.

The outer hub seals (which cause the leaks on the outside ) are simple to replace. But, there are two different seal kits since MB changed some dimensions at some point. The old seals are not easily obtainable so, if you have the old seals and modern replacements, you must also add a new "wear ring". Here's a quote, compliments of the late Jack Russell:

"Now there is one, universal seal for 737.0,1 & 747.0,1 axles. The only
"catch" is that the new seal is changed dimensionally. Circa 1978 the
factory "improved" the wheel seal. They made the inside diameter
larger. The early units have a 136.0 mm I.D. The wear ring the seal
inner surface rides on is appropriate to this dimension.

All later production uses a 140.0 mm I.D. seal, with a correspondingly
large diameter wear ring. If you are making repairs to leaking outer
wheel seals on a 406/416 and it still uses the 136.0 mm ID seal? Then
you must also change the wear ring to the new type as the old seals are
no longer available."


Replacement details can be found here:

http://www.rfspecialists.com/temp/seals/416%20final%20drive%20output%20seal%20replacement. htm

Since I don't remember where I downloaded that page from (it might be Dr Dan's), I simply mirrored it. Thanks to the original owner - come forward and I'll credit you.

The input seals are a bit tougher because the entire portal must come off. There are several web sites that detail this - it's much more work but the actual tech is pretty easy.

Before you replace the inside seals (maybe even the outside ones), make sure your hub vent tubes are clear of debris. If they're clogged, this could pressurize the internals enough to force lube past the seals. Since this seems to happen when you engage lockers, chances are the locker seals need to be replaced also (I guess you already know that ). Unfortunately, this requires disassembly of the axle itself - again, not that technical of a job, just heavy and awkward. Here's another Dr Dan page, describing the fix on a U1300 - I think the 416 axles are pretty much the same ( can anybody confirm that ??):

Unimog 1300 Air Locker Repair

[graphic66]

Those look like the correct locker seals. Not to bad of a job at all. A cherry picker or some sort of lifting tool like a front end loader or fork lift can help getting the axle half out. Or just jacks with wheels. Just make sure your Mog is supported well before working, these things are heavy.

[E-steban]

Thanks for the help and advice above.

Yeah Keith the house is getting closer but still not done. My hardwood installer punctured the radiant floor tubing by missing the sleepers when nailing. I had to tear up all the hardwood (ruined) find the leaks by chiseling up the gypcrete and splice. Probably a 2 month set back and 10K+ !! Luckily he is insured and so am I... whew.

A long time ago Von gave me some seal dimensions and now I cannot find where I filed them. He told me that the seal he uses is 1 mm smaller ID and poses no problem. I would like to have the parts in hand before starting to tear the truck apart. Von, could give me those seal sizes again please ? It is a 1979 Case with discs if that makes a difference.

[E-steban]

for the record:

I spoke to Von earlier today and he said that after about 1976 the wheels take a 140x165x12 mm seal - thanks Von.

[E-steban]

Okie dokie, its only taken me since 6 months but I began to tear into the 406 today in hopes of first fixing the front locker piston seal and then later fixing the two leaking right hand wheel seals. I will post my adventure in hopes that it might help somebody else. Tips and advice welcome. One nice thing is that my infloor radiant heat became functional yesterday. Man is my new garage floor toasty nice. I could lay on it all day long.

First I had to jack the sucker up. Luckily I had what the last owner called a "Mog Jack" - basically a long hydraulic jack. It still took a stack of 4x4 for it to reach the half shaft tube of the front left wheel. I jacked it up on the tube covering the half shaft and then placed wood and a jack stand under my frame. A heavy sucker this beast is, at least for me since I am used to KTM 640s. It was necessary to keep the jack under the half shaft tube in order to have sufficient clearance to remove the wheel.



Next I disconnected the shock absorber.
Then the lower coil spring bracket. To disconnect the upper coil spring bracket I would have to tilt the cab to access the nut and cotter pin which is a bunch more work since I have the FOPS above the cab. The spring will just have to hang there, looks like plenty of room to take the axle out.


Then I removed the daigonal cross brace that goes from the frame to the steering knuckle.
Man are those bolts tight !!! Matter of fact I had to buy a new torque wrench that goes to 250 ft lbs for this beast - $70 at Home Depot.






There is a plate on the front attachment point of the diagonal brace that keeps it from slipping, watch that you put it back the way it is meant to go. One side of the plate has concentric rings the other side has teeth. They mate with their counterparts on the other components. It is pretty obvious which way they go.






Than I undid the cotter pin and unscrewed the castle nut on the ball joint on the end of the tie-rod. That is as far as I got today. Couldn't get the ball joint loose from the tie-rod.





Luckily Autozone will sell you a ball joint extractor set that they will gladly refund your money when you bring it back even if dirty and used. I headed off the mountain to go get the extractor and buy some larger mm sockets and wrenches. Few things in my present tools are large enough for the mog other than my crescent wrench.

Hasta Mañana

----------------------------------------------


Well mañana arrived and armed with larger sockets, larger wrenched (24 mm is the most common), and a ball joint separator I was back at it. My neighbor Dave came over to help too.



Kudos to Littleton, Colorado Autozone for lending me this extractor. Worked like a charm.







After removing both hydraulic lines to the two calipers and the air line to the locker mechanism we unbolted the differential cover. Them we chained up the axle - hub assembly to an engine hoist and slid her out. Pretty easy actually.

[E-steban]

Once the axle assembly was out from under the truck we tried to find where the o-ring was. It took a while. It was not immediately apparent. The notched locking mechanism consists of two pieces - one on the axle and one on the differential side. Where was the o-ring ???!!!! Hmnmm we looked and looked. from the axle we slid out the spring, piston, thrust washer, shim, and still could not find it. Then we took off the drain plug and the spigot where the air line attaches. We looked and looke and finally figured that the piston was acutally two pieces. We used a hooked wire to slide the second piece out ot the axle tube. Lo and behold there was the rubber o-ring, trying to hide from us.



differential side of locker mechanism


axle side of locker mechanism



Visible are the locker spring, inner portion of locker piston assembly, bronze thrust washer, thin steel shim washer and outer portion of the locker piston assembly with o-ring still on splined axle shaft.



Here is the hooked wire we used to take the sleeve that forms the outer portion of the locker piston out with.



After replacing the o-ring with a new one and using scotchbrite to remove a little rust we cleaned the differential cover mating surfaces, applied a little adhesive sealer and reassembled.




I also found that the breather tube (located under the coil spring lower mount) was clogged solid with gradoo.







Reassembled the rest of the stuff, bled the brakes, put the wheel on and we were done with the locker o-ring. About a 4 hour job if you have what you need on hand.

Next on the list were both the right side wheel seals.

[VON]

Steve,
I hope you know there are two o=rings per axle! One on the piston and one inside of the axle housing.

[E-steban]

Originally Posted by VON

Steve,
I hope you know there are two o=rings per axle! One on the piston and one inside of the axle housing.

Uh oh..... nope did not know that.

Where on the inside of the axle housing ?
I looked up and down in there, even cleaned out the residual oil and dirt and saw nothing. I guess that is why I am doing this thread so that there is a better guide available. I guess I will be taking it all apart again, I needed the practice.

[coachgeo]

Originally Posted by VON

...two o=rings per axle! One on the piston and one inside of the axle housing.

do I remember correctly that it is the one on the inside of the axle housing that is usually the one that causes problems?