[Gerald]

I used the Lucas hub oil, which you can find at truck stops and many NAPA stores if my memory is correct. And, that oil is clear…..not red.

Your Prevost manual will have the specification.

[Gerald]

To further confuse the issue, the tag axle hubs look different from the steer axles. They are metal with one big rubber plug. The driver side was empty but not dry, the passenger side contained old gear oil. The first pic is the steer ale hub, the second pic is the tag axle hub.

.

What should be my plan for the tag axle hubs? Do I fill them with grease (what kind?) or do I fill them with oil?

Thanks, Gerald

[Greg]

Gerald,

I don’t think you can suck it out because I believe the bearing and the nut and safety washers are all going to block access to the low point on the hub. If you don’t have the hub covers with the drain plug it is just as easy to pop the 6 screws out, remove the hub cover and let it run down your wheels onto the tires.

Just kidding about that. You can catch it if you pull the wheel, If that is not possible then you will have to sop up the mess or make a trough.you can hold under the hub cover to drain it away from the wheel and into a pan.

I would use the 85/140 or the nearest equivalent since at least half of the driving is expected to be in warmer weather. When you get it refilled and all back together just make sure the tiny pin hole in the rubber plug is open so the hub can breathe. With the thicker lube it take a while to drain past the bearings so be patient.

[Greg]

Thanks Jon, will do.

So both hubs should be filled with oil? The tag hub is not the grease type?

We are about to go on a 1000 mi trip. Glad I checked the hubs.

Gerald

[Archived]

If you can park on a side slope or otherwise raise one side of the axle the oil will drain a little faster.

Yes,gear oil in the tag hubs. You should crawl underneath and see if the inside of the tag hub is wet. The one that’s near dry should show signs of a leak somewhere.

[George]

FWIW, I would not refill to the top line.

Our shop policy was refilling to a level in-between the two lines. The reason being when heat expansion kicked in the oil was overfull over the top line.

Ditto ……on the vent hole in the center of the rubber plug. Many a hub oil failure and grease mess when the vent hole plugged. The next event is the rubber plug blows out.

[Archived]

Don’t
forget to block and brace if you get under it Gerald and be sure to
not overfill.

Just a note – When I had the new brake rotors installed on Peter’s
Royale, after I got it home it took almost two days of slowly adding
oil to the hubs to get it full. Like Jon said, it’s a slow process,
but mine was completely dry after dis-assembly of the rotors, so you
won’t have that much of a problem. After setting overnight when I got
it home, the oil didn’t even show in the glass. It was full when I
left the shop, but takes awhile to get it back to the correct level.
Wonder how may hubs out there are low without the owner knowing.

[Archived]

Thanks everyone!

Got them changed. After I cleaned off the tag hub covers, they were plastic as well and had a fill line. I’ll watch them closely from now on.

There are so many things to check/fix when you buy a used coach. This one slipped through until now. It motivated me to do a transmission and differential oil change real soon.

Gerald

[Archived]

Definitely gear oil, never heard of trans fluid in hub bearings. I use same in drive axle as in hubs.

[Archived]

Gerald, there are in fact a lot of details regarding the maintenance of your coach. There is no way any one of us has the ability to track all of it without some type of logbook and maintenance check list which begins with the Prevost maintenance schedule which can be accesses and printed from their web site.

But we also have the generator to consider as well as the routine maintenance tasks the house requires.

Unless you have service records I would suggest you methodically go through your coach as you suggest you will and treat all maintenance as due. At least then you have a starting point and you know the status. After you get through the process of getting everything up to date which is both time consuming and expensive you will see that due to the various time or mileage requirements keeping up with the maintenance is less expensive and time consuming because it all begins to spread out.

The comment above about checking for hub seal leaks is a very good one and the fact hub grease was down is a strong signal there may be a leak. Those hub seal leaks require immediate attention because at some point they affect the bearings, but equally important is the fact those leaks compromise the brakes. Oil soaked pads and discs don’t work.

[Greg]

What Al cautions against is what I can concur with as well; do not fill to the second line, but to the midpoint at most, or you are asking for a problem. ATF is incorrect, use gear lube as the others have pointed out. My two cents.

[Ed]

For those of you who may not be aware, Ken will not admit it, but when we talk about fluids and lubricants he is the go to guy and I look forward to his 2 cents.

[Archived]

This cut away shows Chicago Rawhide RV/Bus new hub seal, micro vent, magnet. Price on this part is around $200

[Archived]

Well, I guess I have to come clean. I did fill it up to the line pointed to by the fill arrows. What is going to happen? Is the oil going to foam?

Edit: I lowered the level to between the two rings. Should be good to go now. Thanks for everyone’s advice!

Gerald

[Greg]

Too much oil usually ends up making a mess. I suspect, but do not know for sure, that if the oil blocks the little pin hole in the plug (that allows the hub to breathe) it could pop the plug or push out the seal.