I was crawling around under my bus today just looking for problems and came across a patch of gear lube running down between the duallies on the drive axle. I know, I know, look for trouble and you will find it. ::) Question I have, to replace the seal on the axle, will I need to use a hub puller of some sort, or will it all come apart by removing bolts and pulling apart by hand. Can I leave the drum assembly on it after disconnecting all the lines, etc. and will the axle come out of the pumpkin with the hub and drum. I've never torn into this part of a bus before and any help will be welcome. All I can find in the Prevost manual covers just the differential and not the actual housing. Thanks in advance, Will
hey P.P. what you will need to do is block the coach solid, then jack the axle up just so it will clear the dirt LOL or if you are lucky the pavement. take the axle bolts out, NOTE put a bucket under the axle to catch the oil when you take the axle out. Some axles have 2 or 3 threaded holes that you can put a bolt in and pop it loose when you tighten them up. and then pull it out and you will see a big nut that is locked in, take it loose and some have a spacer that has holes to align proper locking of the outer nut . and some have a ,like a washer that is flattned against the outer nut.. Are you confused yet? now you can take the inner nut off and the bearing and put a piece of plywood under the wheel and take a piece of metal and put a little oil on where the wheel will slid on it and pull it off and inspect the inner shoes and see where the oil is coming from, usually the seal is shot. some drums have the seal bolted in and others are just pressed in with a hammer and board. check the linings and if there is a lot of oil on them REPLACE them as it is not worth the risk of burning them up let alone the danger of not stopping. l have found that a big truck parts place can get or may have in stock what you need. I replaced mine on 2 of 3 coaches that I have and it is not that hard to do. HAVE FUN
Gomer
Thanks Gomer, I'm going to print your post and use it for a reference. Most of what you say makes sense, but you do have me a little confused on the washers. I'm hoping to understand it better when I'm looking right at it. It sounds like I need to run up the air bags, block her solid, and then dump the air and jack up the axle just enough to clear the dirt. (Yeah dirt, but at least it's high ground and not a wallow). I'm hoping that the shoes aren't compromised, as the leak seems to have started since its been parked. Doesn't appear to be any spray from being flung out while on the road. But then, it might have just found its way out. If I get in a bind, I'll cry out for more help. Thanks again, Will
Will,, Your welcome and PLEASE make sure the coach is blocked solid as we,bus nuts,don't like sending out condolence cards to families that has both gotten hurt or killed by fallen coaches.. The nuts will pretty much explain themselves as you look at them. When you re-assemble don't overtighten the main bearing nut as it will overheat and may catch on fire and/or damage just what you fixed.
Gomer
Thanks Gomer. Very helpful writeup you did, i am going to save it too. Lots of times someone will ask a question asking for help,,, and the following posts will have lots of advice, but not much help. There is a difference. Thanks again!
Hold the phone...
Take lots of digital pictures at each stage, so you can get it all back together.
You just have to put a jack under the axle and raise it enough to slide a piece of sheet metal with some oil smeared on it so the tires can slide sideways. You have to find the balance between hanging the tires and squeezing them on the ground, in order to pull the assembly off the shaft.
The state of the air suspension doesn't matter for this job.
The parking brakes must be released, (or you must back off the slack adjuster all the way) otherwise, the shoes won't let the drum and the rest of the assembly slide off, so the bus must be aired up, and the coach secured, for sure, against forward or backward movement.
Remove all the axle fasteners (not the wheel fasteners) and whack the end of the axle with a sledge hammer. The axle will bounce out enough for you to get your fingers in there and pull it out. Treat the splined end like it is gold, no banging, no dirt, or falling against stuff.
You want to invest in the proper sized axle nut socket, changing the axle seal is a maintenance chore you will have to do periodically, or end up with the leaks and an unneccesary brake job again.
A crow bar, or 5th wheel puller is of great assistance when yanking the wheel assembly off the axle. Grab at bottom hand hold in rim and a little lifting effort to counteract the droop from gravity seems to work well.
If you have a lube leak of that magnitude, I expect you will be replacing the shoes. Not a big deal. Take them off, and make the rounds to your local vendors and trade them in. Should be somewhere $50- $75 a pair for re-mans with your old ones to trade in. The kit should include some fresh springs. If not, get some.
The springs require a bit of leverage to get into place, depending on your configuration. Vise grips, big screw drivers, a piece of wood, if you use your head instead of your muscles, there's always an easy way to get these things together. Or many hard ways....
Also, get a new gasket for the axle. There is a difference between cost-effective and stupid...
And you might as well do the other side, then you know what is what.
You should have something substantial to place under the axle once it has been lifted.
JACKS MUST NOT BE TRUSTED to hold the bus up. They are for lifting it, other stuff should be used to hold it, or catch it, WHEN, not if, the jack fails.
Only those who trust jacks, are let down?
And if you end up with new shoes, you will have to learn in a hurry, how to adjust your brakes, and how to burnish your new shoes. The new shoes go out of adjustment quickly, as they take on the shape of the drum.
Make no mistake, get it wrong, and your bus won't stop...
I don't know many mechanics who would turn down some cash to come and give you some help, especially if you tell 'em you are going to do the heavy part and they get to supervise. Get over to the local bus garage and make some discreet inquiries.
keep asking your good questions!
happy coaching!
buswarrior
First check if you have any breathers on the axle housing and make sure they are not blocked.
Thanks Tony, but it's not the breather. Couldn't get that lucky, :'( It looks like as soon as the rains stop, I'm going to be using Gomer's and Buswarrior's instructions, which appear pretty straightforward, Thanks guys. I can't believe I've never had an axle seal go on a bus before, yet it sounds pretty common. Must be doing something right. When I get the parts, I'll (discreetly) pick the mechanic's brain too. And yes, Buswarrior, I take lots of digitals when I do a project, the memory isn't what it used to be ???
Thanks again to all of your help, I really appreciated the heads up on breaking in new shoes, Will
Will, just because the shoes are covered with oil, they are not bad, just dirty. There are many products that will remove the grease. I don't like to use gasoline but I have in the past. It is necessary to use a screw driver and clean the gear oil out of the rivet heads on the drum side of the shoe. A pressure washer could also be used. If they aren't worn out I'd keep them.
In the interests of balanced reporting...
Brake lining material is porous. The lubricant that has contaminated them soaks into the the lining material, making it impossible to "clean".
Yes, you may be able to recover their appearance, but as you use the brakes, this soaked-in lube is able to involve itself on the friction surface, reducing that brake's effectiveness.
You now have an automatic luber installed?
Since the other brakes are involved in a regular brake test, it is very difficult to measure whether it is "right" without a drive-on performance based brake dynometer, and after all that work, if you put it on one, it won't be "right"
You will find many mechanics/foremen and owners who claim there is no problem with this practice.
Remember where their opinions come from: They are driven by the desire to save every penny, or cover up the fact that they screwed up a seal on install after a new brake job, or should have changed the seals sooner, or.... the other brakes mask that this one is weak on the road test, and if the bus rear ends something later on, it's the driver's fault, and they fire him, they do not go back and check that one brake that would have stopped the bus so many feet sooner, if it had been gripping properly.
You will NOT find an engineer, whose specialty is braking systems, support this practice of "cleaning" contaminated brake linings.
You have to use many dollars worth of some cleaning agents, a bunch of time, making a big mess, versus the $50 to $75 for a set of re-man brake shoes?
The cost benefit is awfully skinny, considering what is at stake.
Your choice.
happy coaching!
buswarrior
If they're contaminated, they'll be replaced. The thought of cleaning them is very tempting, but Buswarrior's comment makes sense. Because they're porous, the first time they heat up the oil will resurface and I'll probably be lucky if I just let out a lot of smoke. I don't want to consider what unlucky will be. No, money doesn't grow on trees, but there's a difference between frugal and cheap. If the jobs worth doing, it's worth doing right. Thank you for trying to save me some money though, Will