Leaking Wheel Seal

[dale farley]

I pulled my wheels this morning to check everything before I leave for a long trip this weekend, and I see I have a significant oil leak around the axle. I have never pulled one of these before, and I am wondering if there are any tips that anyone has. I see the leak is behind that outside hub, so I assume I need to remove that axle, the large nuts behind it and the bearings. I assume it is the inner seal that is leaking.

[dale farley]

I had to release the emergency brake to remove the brake drum. Can I engage the brake again now that I have the drum off, or will that cause the shoes to expand too far? I'm not sure if he emergency brake actually expands the shoes????

[Jon Wehrenberg]

Dale, we forgot to talk about that. Cage the emergency brake becauase you will get overtravel on the slack adjuster and it may do some damage, likely to the springs or may push the "s" cam too far.

[hhoppe]

Dale please recall my sad experiance when the seal was replaced by a DD repair shop and the bearing was put back in dry of any lubricant. In ten miles it seized uo , broke the axel and required a major repair by the axel surgeons. :eek:The bearing only receives it's lubrication from the differential and if assembled dry without pre-lubbing or tilting the bus prior to hitting the road will be disaster. There was a previous post describing sequence of assembly and tightening the bearing nut, it will be helpful to review. Lew had a similar experiance to mine and I hear it's all too common. Good Luck

[dale farley]

Jon-Harry,
Thanks for your input. I put grease on the bearings and pumpd oil over them. I also pumped the cavity full of oil until it ran out before I installed the outer wheel bearing. I will also tilt the axle so the oil will run into that side. Hopefully, everything will be okay.

[JIM CHALOUPKA]

Dale, did you use the Stemco seal and nut, or did you stay with the tanged lock washer and nut and standard seal?

JIM

[dalej]

Dale,

When I work on any of my axles, I keep the emergency brake released so I can keep any of the braking action from getting in the way.

I have my bus on stands, so I don't worry about it rolling.

[Jon Wehrenberg]

Do you back off the slack adjuster Dale J? Or do you cage the brakes?

[dale farley]

Jim, I used the same seal that was on on the bus. I am not sure if it was original or not. It looks like the parts manual shows a two piece seal, but the one I used was a one-piece. The invoice says CR Scotseal.

I didn't set the emergency brake after I pulled the brake drum. I scotched the wheels so it couldn't roll. First time I actually used the X12 wrench to torque the nuts after I removed/installed them with a 1" air wrench.

The most useful tool I used today was the wheel dolly I purchased from Northern or Harbor Freight for $39.95. It made removing and installing the wheels a breeze. With one hand, you can roll the wheel into place, raise it up or down and rotate it so it lines up with the studs. I fought with the wheels the last time using a pry bar to position them.

[JIM CHALOUPKA]

Sounds like you had a fun day. :)

JIM

[Orren Zook]

Jim, I used the same seal that was on on the bus. I am not sure if it was original or not. It looks like the parts manual shows a two peice seal, but the one I used was a one-peice. The invoice says CR Scotseal.

Dale, If you are replacing a Stemco two piece seal with a Scotseal or National one piece seal, be sure to remove the wear ring that is used as a sealing/wear surface on the spindle with the two piece seal that Stemco makes, you can pull the one piece seal up over the wear ring but this will ruin the new seal. On another note, if you overfill, the excess oil will usually leak out through the weep hole in the hub cap plug.

[dalej]

Do you back off the slack adjuster Dale J? Or do you cage the brakes?

Jon, I have just been turning my brake adjustment until there is no pressure on the cam.

Dale, Did you have a good way to remove the hub? I used a floor jack on the driver hubs, they are a beast for weight.

[Jon Wehrenberg]

I suggested the floor jack to Dale F. I did forget to mention that when installing it is critical to align the seal so as the hub is slid back into position nothing is levering against it and that both bearings are in place to keep the hub perfectly aligned. The seal is fragile and if it gets deformed it will leak.

[dalej]

Jon, that was a very important part to leave out. :)

[dale farley]

I don't remember removing the brake drum, but I assume I had to use the floor jack. I removed the spindle without any assistance.

I replaced both of them using the assistance of a floor jack. I did not have the outside bearing in when I slid the spindle back on the axle housing, so I hope I didn't deform the seal. If it leaks, we know who I can blame since Jon didn't mention about having both bearings in when I slid the seal on. Or maybe I can blame this on my parents for something they did or did not do when I was a child!!

[dale farley]

Orren,

I replaced a one-piece seal with another one-piece. The one that was in there may have been leaking because no one told the installer to make sure he had both bearings in the housing when he slid the seal in place.

I am going to recheck the oil in the differential this morning to make sure the level is correct.

[Joe Cannarozzi]

It is not hard to get the inner bearing cocked on the spindle just slightly enough to make it feel kike the hub is back tight when it is not.

When reinstalling tighten the outer nut with a cheeter bar and crank it down as tight as you possibly can then before you back it off take a drift and a sledge and give the hub a wack or two and sometimes what you thought was tight will be sloppy again due to the inner bearing getting straight.

From that point there are numerous techniques to do the final adjustment.

Some back the nut out 1/2 turn releasing the bearings and then tightening back 1/4 turn, this is what I do for the drive hub.

Some back it off and tighten the nut by hand as tight as you can get it and leave it there, this is what I do for the tag and steer hub.

Some use a tourque rating and wrench.

Whaterer method make sure your inner bearing is completly seated.

One thing I also do is count the exposed threads beyond the outer nut before you disassemble it so you have a good idea when you put it back togeather if you have completly seated the bearings.

[dalej]

I couldn't get my break drums broke loose so I had to remove the whole assembly at once, it's one heavy item when it's all together.

[dale farley]

Joe, I torqued the inner nut then backed off a little. The outer nut I torqued down and made sure I had the same exposed threads as when I started.
Dalej, I can't imagine having to remove the whole thing at one time. That would be heavy! In retrospect, I don't think I used the floor jack when I took off the drum or the spindle. I did use it to replace each of them.

[Jon Wehrenberg]

Actually to replace a hub seal you do not even have to take off the wheels.

Joe posted a long time ago he uses two sheets of steel with oil or grease between them and the axle jacked up enough so the tires are barely touching the top sheet of steel. Then with the axle nuts off he just slides the entire assembly off and out of the way to get at the seal.

He reverses the process to put it back together.

There is a dual wheel lifting device with a hydraulic jack that Prevost uses in lieu of the two sheets of greased steel. If you replace a lot of seals this is probably the way to go, but with that much mass I am very uncomfortable with accidently banging on the back of the seal when installing it and not realizing it has been damaged.

I disassemble everything, including the brake drum because I can't and won't handle that much weight by myself, and because I have better control putting the hub back on. So far I have never had a seal I have replaced leak by doing it my more time consuming way.