Wheel seal....

[Iver]

Quite a while ago I asked for suggestions regarding why my tag axle wheel was dragging with a small application of the brake pedal.
Some thought it just might be rust from sitting.  Some thought it might be low pressure in the air bag.  Even perhaps the slack adjustment might be incorrect.

All good suggestions.

Turns out when I later developed a leak in that wheel seal and removed the drum,  one brake shoe was badly cracked and one brake spring was broken.
Mystery solved.

So...I am about to replace the seal and redo the brakes.  There is not a wear sleeve on the hub. Do I need one?

Just trying to understand the action of the seal.  Does the inner rubber ring spin on the hub or does the seal spin around the rubber ring when the wheel is turning?

          Thanks, Iver.

[luvrbus]

Iver the way you are describing the seal you have the type that does not use the wear ring the seal spins inside the seal itself, good seals if not that type suggest you change over wear rings are becoming obsolete with that type seal

good luck

[gumpy]

MC9 uses a seal wiper. The inner rubber is sealed to the wiper and the seal spins around the inner rubber.  You can see the wiper in this photo: http://www.gumpydog.com/Bus/MC9_WIP/Mechanical/Tag_Axle/010513.24.assembly_after_washing.JPG

I don't have a photo showing replacement, but it's basically the same as the front. Chisel off the old one. Heat the new one to expand and
install it. I used an old bearing as a slide ram to install the new one, or tap them lightly with a hammer and piece of wood.
Put a dab of RTV on the spindle before seating the wiper to prevent seepage
between the wiper and the spindle. Also a dab of RTV on the wiper before seating the seal.

[Iver]

Thanks Clifford and Craig,
  Craig, I checked your site before and noticed I didn't have the wear rings which you show.
I asked at the parts store for a wear ring and they said this type of seal doesn't need one as long as the hub is not damaged where the seal fits.

I guess I'll check the hub and go ahead and install the wheel and see what happens.

The book says fill with 30W oil.  Others say gear oil.  I'm leaning toward gear oil 80W-90W.
    Any thoughts....
Thanks,  Iver.

[Chopper Scott]

Just make sure you don't combine mineral based oil with gear oil. You can smell the difference. That makes a mess. I use regular 80/90 weight gear oil.

[edroelle]

Use your fingernail and check for a groove on the bottom of the spindle.

Secondly, Luke suggests using grease rather than oil/gear lube in a motorhome application.   I have changed 1 of mine to grease so far.

Ed Roelle
Flint, MI

[JohnEd]

I read a short while back something that knocked me onto my heels.  Gun folks were trying different stuff to stop rust during storage.  First shock was that WAX doesn't stop moisture worth a darn.  Really?  That seems counterintuitive.  Then the block buster....petroleum oil DOESN"T LIKE steel.  Say what, I said.  They dipped a iron sheet in gear oil and hung it in a wet box and it rusted in days and you could track the rust down the sheet as the oil migrated further and further leaving a perfectly oil-less surface.  Now just guess what won hands down....synthetic oil.  Seems it REALLY LIKES steel and clings to it like forever.  I have pulled wheels on my RV that have had rust half way up the bearing.  Half way up.  I was baffled but I knew my marine grade grease was NOT the culprit.  WRONG!  Charge the bearing with the appropriate lube in the synthetic of your choice.  The times they are a change'n.

[gumpy]

I use 90wt in my wheels. I think it's actually 85w-90 or some such nomenclature.

I don't know about the grease vs. oil. Obviously grease works well in cars and other applications. I don't see why it wouldn't work in the bus. But, I can't really see changing for no
reason if the oil is working for you. Now, having said that, I've had two seals go out on my in the last couple years.

As far as the synthetic information, that's interesting. I'm not a big synthetic oil user, primarily due to cost and life cycle. But it will be interesting to see if any more comes up on this.

[JohnEd]

Gumpy,

You have to pull the wheel apart to check and repack.  I think that grease is used because it sticks to the moving parts and continues to lube. Old school.  I don't know if it has more lubricity than 90 wt but I think you can get grease in a number of weights.  Greases have high temp drop points cause the bearings they lube get really hot.  With 90 wt I think the oil would tend to carry the heat away and you can check it with a visual.  Regardless, syn is proved to run lots cooler and have more lubricity than any Dino stuff.  And it stays on the metal and prevents rust.

I am changing EVERYTHING over to syn in all my rolling stock and my gun oils and greases.  Please advise me if you get contradicting info cause everything I read says it's only drawback is initial cost.  I think that is demonstrated to be easily recoverable.  The engine oil I will change only after an analysis says I should and I have been told you get a pretty good feel for how far it will go after your first go round.

Nice to hear from you and please don't think I am talking down to you...I know who you are and it is my aspiration...

John

[Iver]

Craig.....

What type or brand of seals did you have fail?

The one I just bought was a SKF  Scot Seal.  Seemed fairly expensive. However it is the only one I've had to buy.......so far.

          Thanks,  Iver.

[gumpy]

Nice to hear from you and please don't think I am talking down to you...I know who you are and it is my aspiration...

I don't generally think people are talking down to me. Especially on this board.

This synth sticking to metal stuff is new info to me, and I just don't have enough information about it to be knowledgable.
Same with the grease pack.  I just don't know if it makes sense to change them if they are working well. The sticky synthetic thing is interesting, though, and could add a new layer to the
issue, considering my bus sits about 10 months out of the year.

I do know I find it easer to tear down a hub that's filled with oil than with grease. Easier to get rid of the old oil than to get rid of the greasy gasoline after cleaning the parts.

Also, on my autos, I change the oil at 4000 miles. The synthetics I've looked at recommend much longer (some were 1 year or 15000 miles). I can't condone that kind of run time, and it
doesn't really make sense to do an analysis vs. just changing the oil due to cost of the analysis.  It might make sense on the bus, where  you have 8 gallons in there. I change the oil in the bus
at a target of 8000 miles, which typically comes out to once a year.  Usually in the fall just before I put it to bed for winter.

Iver, I think the seals were National, or maybe Scot. JD, at C&J Bus Repair seems to think the primary cause of seal failure is the bearings being set too loose. I suppose it's possible I had
them too loose. I set them my hand, and don't have a gauge to tell me amount of movement. It's also possible that one was leaking under the wiper as I don't think I used RTV the
first time I replaced them. Also, one of the seals that was leaking was one I had initially installed on the tag, and then moved the hub and drum as a unit to the front, and did not replace
the seal, so I suppose I should not have been surprised that one leaked.

[rv_safetyman]

A couple of years ago I switched to heavy straight weight gear oil (135 as I recall - had to order).  That seemed to help a small weep I had.

I monitor several of the stick and staple boards, and many of those folks have switched to Lucas Hub Oil. The reading I have done, suggests it is good stuff.  At the 2009 Quartzsite rally, a fellow brought some and we all played with using a finger test.  Seemed to have great lubricity and reminded me of STP.  A year ago you had to really look for it.  Now it is at every truck parts place and truck stop.

I have purchased a couple of bottles and will convert when time permits.  They say you can add it to your existing oil, but I hope to drain the hubs (no special effort to clean bearings) and then put the straight stuff in.  It is said to "cure" seal leaks.

Jim

[DaveG]

There are a few different seal designs, and one of the least favorite is the type of seal (either rubber or rawhide) that rides directly on the spindle.
The second is a similar type, but is designed to ride on a wear ring (think Speedi Sleeve) that is driven onto the spindle. This type of wear ring should have some non hardening Permatex type stuff on it to prevent oil/fluid migration.
The other is a seal that rotates within itself, so that the seal is stationary on the spindle and in the hub bore.
Most seal companies make both types/designs.
Visit Stemco's website for more information.
The big seal manufacturers are Stemco, C/R and National
I know that Stemco publishes an industry standard procedure for wheel bearing tension/tightening...the bottom line being that you are looking for about 0.003" of end play (some say .001-.003, others .003-.005) Whatever procedure you use, it doesn't matter as long as you achieve this end play.