Oil fill for bearings.....

Iver · June 08, 2010, 09:31:38 PM

When I finished replacing the seal on the tag axle and put everything back together I proceeded to refill the bearing cavity with oil.
I filled it up to the bottom of the hole in the clear plastic cap and then I realized there was a line around the plastic cap and an indicator which
said "oil level".
It looks as though I am over filled. I can remove some oil. Although it sure doesn't look like much oil when you only fill up to the ring on the plastic cap.
Iver.

JackConrad · June 09, 2010, 04:50:35 AM

Filling only to the line allows space for the oil to expand when it get hot. Jack

James77MCI8 · June 09, 2010, 08:24:29 AM

What weight oil did you put in? Just curious.

bobofthenorth · June 09, 2010, 01:03:15 PM

I can't speak for Iver but when I recently replaced a seal in my tag (after it leaked when we did the brakes and used a Stemco seal) I used Lucas hub oil. It took some looking to find it but Mohawk/Husky had it in the trucker's convenience store in Regina. And I used it on the recommendation of Jim Shepherd so if it leaks I'll be on the warpath headed for Colorado. The previous owner/moron painted the glass in my hubcaps so I can't actually see the level without taking out the rubber plug. If I wasn't so broke I'd buy new ones.

Iver · June 10, 2010, 01:57:49 AM

Thanks Jack,
I wondered why they only wanted oil up to that line. Looked pretty minimal. Now I know.
I used 80/90 wt. Never really knew about "hub oil".
Thanks, Iver.

Ednj · June 10, 2010, 04:41:12 AM

I'm pretty sure my book says 40wt motor oil in the hubs.

Utahclaimjumper · June 10, 2010, 07:12:39 AM

Another reason,, if much above the "line", the plug will seep, they dont seal all that well. 80W90 or 100 synthedic is great and stops wear.>>>Dan

JohnEd · June 10, 2010, 07:35:06 AM

Synthetic.....for the win! Verify this.....syn has a more steady viscosity than Dino, lubricates way better, has ZERO sulphur and runs cooler. Result is less wear and better MPG. I don't know that I would go with 100 syn. Get the "equivalent" weight of what you are replacing and I think the syn is marked that way. Note that it is "thinner" than the same wt in Dino. Use thicker oil to slow a leak but that isn't the fix. Although the thicker Dino lubes better it is also more resistant to flow and harder to push around and mainly, in my eyes, the OEM could just as easily have specked a heaver wt and chose not to.

If I hear a rod start to rattle at start-up or a bearing growl in the diff I go for the Lucas or Motor Honey or STP. Otherwise I steer clear of those products.

Wonder what Dallas or Sean or Cliff has to say.

My 2 cents

John

Frank @ TX · June 10, 2010, 08:05:16 AM

Hi Iver,
The book does call for 40W motor oil in the hubs.
BUT some folks use 80/90 W gear oil.
The thought is that the bearing with 80/90 will run a little hotter and try the surge the water.
When I first got our bus I removed the hub oil and cleaned things out a bit.
There was some water in the hubs with the oil so I went to the 80/90 to refill the hubs.
About every other year I get a thin tube and get some oil from the bottom of the hub, so far no water.
Frank

TomC · June 10, 2010, 01:05:08 PM

80/90W and 80/140W are the two oils of choice in either mineral or synthetic at Freightliner. 40 is too lightweight for wheel bearings. Good Luck, TomC

bobofthenorth · June 10, 2010, 01:29:50 PM

40 sounded pretty light to me. I know the Lucas that I added poured like stiff corn syrup. It would slightly pile up in the cap as I was adding it. My thinking was that thicker oil would be better because it wouldn't drain off the bearings. With the amount of time our rigs spend sitting I think that's the biggest issue for the wheel bearings. Of course reading (and following) the book is likely a good idea to but I confess I don't do it very often.

bevans6 · June 10, 2010, 01:43:20 PM

40 weight engine oil is about the same viscosity as 90 weight gear oil. they are measured on different viscosity scales. there is no reason to put gear oil in a hub bearing. Gear oil is formulated with extreme pressure modifiers to allow the sliding surfaces of hypoid gears to survive. There are no hypoid gears in hubs, from what I recall. Engine oil, in particular our engine oil with minimal additives and viscosity modifiers, etc, is really well suited to use in bearings and I just add a little SAE 40 when I look at them, if they need it. You won't hurt anything with 90 weight gear oil, it is what is inside the rear wheel bearings after all, you just don't need it. It's not better for the application, you aren't doing the bearings a favor by spending more money.

chart with comparative viscosities. http://www.bobistheoilguy.com/visc.html

Brian

JohnEd · June 10, 2010, 03:26:04 PM

Quote from: bobofthenorth on June 10, 2010, 01:29:50 PM
40 sounded pretty light to me. I know the Lucas that I added poured like stiff corn syrup. It would slightly pile up in the cap as I was adding it. My thinking was that thicker oil would be better because it wouldn't drain off the bearings. With the amount of time our rigs spend sitting I think that's the biggest issue for the wheel bearings. Of course reading (and following) the book is likely a good idea to but I confess I don't do it very often.

That sure made sense to me also Bob. Maybe the Lucas has additives but typical Dino base stuff will slide right down metal and leave it perfectly clean and vulnerable to rust. I read a test where they used motor oil, bees wax, synthetic and a few others for a comparison. The bees wax was one of the first to fail and start rusting. BEES WAX isn't water proof?

? Shocked. Min oil and motor oilalso started rusting at the top of the plate that was in the humidity box. with each passing week the rust would drop down another 1/2 inch and the top started to look like it had been doused with acid. Only one test plate remained rust free throughout the months test period.....SYNTHETIC. The chemist said that Dino really didn't bond with meta but stayed on top and was prone to sliding down a vert surface and leaving the metal clean. The syn really LIKED metal and penetrated into the surface of the metal and would cling there forever, figuratively. One that failed was thick gear oil.

I have pulled wheel bearings that had rust half way up the race and the rotor was rusted half way around. I never understood how that could happen till I read this recent article. Those wheel bearings had sat and the grease had migrated down and the condensate had rusted the upper portion of the race. BOAT WHEEL BEARING GREASE is what I had put in there.

One of the reasons to use a thinner grease/oil is to allow the oil to carry the heat away and transfer it to the rest of the axle or wheel. Using a heavier grease will impede that cooling. Probably wouldn't matter unless you were in Phoenix in Aug. When Syn first hit the market I was told that the truckers with the differential temp sensors and coolers could see an actual 20 degree drop in diff temp after switching to Sys. Maybe I missed something through the years but it seemed to me, back then, that every trucker would have everything running in Syn but that hasn't happened. The knife people swear by it and so do the gun guys.
The loggers put Lubriplate on everything they will be leaving outside all winter or for a couple years and it hasn't failed yet. I think it is a synthetic but has petro in it also..

John