Re: [MV] 2 1/2 ton rear wheel seals

From: R. A. Moir aka RAM (cyclopsram@starband.net)
Date: Sun Aug 25 2002 - 17:48:09 PDT


Well, ya know they have lasted 50+ years in all kinds of stuff with both
seals and we are not going go do the later generational engineering here....
If you put them together correctly as the folks at Rockwell designed them,
and maintain them, they will last another 50 years. the bearings were
designed for GAA and that is what they like... Not GO, H2O, Amsoil,Mud or
other stuff....I agree with Ronzo on this one.... welcome back to the MV
problems.... RAM
----- Original Message -----
From: "Ron" <rojoha@attbi.com>
To: "Military Vehicles Mailing List" <mil-veh@mil-veh.org>
Sent: Sunday, August 25, 2002 12:27
Subject: Re: [MV] 2 1/2 ton rear wheel seals

>
> When I pulled my rears due to oil leaks past the inner seals, I found
> little "rabbit turds" of grease on the top of the axle between the
bearings
> and inside the hub. The 'turds' were created by blobs of grease being
rolled
> inside the hub in the oil inside the hub.The bearings had all of the
grease
> washed out of the outer bearing and not much left in the inner bearing.
> So, greasing the bearings and leaving the outer seals off seems
> counterproductive. If the seals could hold oil that well, they wouldn't
leak
> out on the inside of the wheels at all, right?
> Most common cause of failure of the inner seals is the little piece of
> cork being left out that goes into the keyway under the outer bearing and
is
> compressed into place by the tang on the outer seal. This allows oil into
> the hub area in the first place. Again, the devil is in the details....
> In 2 of the PS monthlies I've seen, one in the early seventies, and
> again in the early 80's was a little blurb to the M35 mechs to make sure
> they made sure they put these cork pieces in to avoid early seal failure.
It
> was also in a multi page MWO or TB that I can't seem to find at the moment
> (lost in the
> network hell on one of my machines).
>
> Looking a little deeper, I came across this....
>
> from TM 9-8000 PRINCIPLES OF AUTOMOTIVE
> VEHICLES section 19-11, Para a) Synthetic rubber seals, "Fig 19-4
> illustrates the effect of pressure on lip seals. Internal pressure
developed
> during operation forces the sealing lips tighter against the rotating
shaft.
> This type of seal will only operate effectively against fluid pressure
from
> one direction."
> This would tend to explain why they use two seals. The inner seal
keeps
> water from entering the hub from outside. The outer seal keeps the oil
from
> reaching the inner seal and leaking out. You use grease on the bearings
> because it tends to stay put in the hub if it does get flung off. The
seals
> at opposite end of the hub are there only to keep out OUTSIDE water, but
> this requires the outer oil seal to protect the inner seal.
>
> That make sense?
>
>
>
> Ronzo
>
> ----- Original Message -----
> From: <MVTrucker@aol.com>
> To: "Military Vehicles Mailing List" <mil-veh@mil-veh.org>
> Sent: Sunday, August 25, 2002 8:57 AM
> Subject: Re: [MV] 2 1/2 ton rear wheel seals
>
>
> > Rick,
> > Interesting question and I'm looking forward to the responses.
> > Years ago when I was doing my first seal installation, I
> > stopped in to our local National Guard motor pool to ask
> > some questions. What a learning experience! They pack
> > the bearings with plain old chassis grease, the yellowish
> > stuff, on the initial installation, then leave the outer seal
> > out so the gear lube takes care of the bearings. I still
> > pack the bearings with blue or red grease and install both
> > seals. I'm not so sure that the inner seal would hold up
> > very long against the light (compared to grease) gear
> > lube.
> > Joe Young
> > www.joeyoung.com
> >
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>
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>



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