new grease turning to oil?

Has anyone had problems after regreasing front wheel bearings and having some grease turn to oil and run out the cap? I've had it happen before with NAPA's brand of grease in 4 lb tubs and now with Valvoline's extreme pressure, high temp, multi purpose red wheel bearing grease. I had been told not to use gasoline to clean hubs and bearings, that it would damage the new grease, but there have been many hubs that were caked full of abrasive grime. I was thrilled to find the latest set of hubs had been taken care of and didnt need any more than wiping out. So no gasoline in these, but the grease still drips oil. I expected Valvoline to be good quality grease. Any ideas?

Feel the hubs when the "oil" starts running out. I will bet you that they're probably almost too hot to touch.

Are you perhaps tightening the bearings too much when you put them back together? Did you replace the seal and gasket?

I have seen wheel bearing grease completely break down and turn to oil, but only when those bearings SHOULD have been repacked 20 or 30 years ago. I have never seen it happen in hubs that recieved regular maintenance.

I've been trying to stay out of grease related topics lately, but they seem to pop up like deer in the headlights.

The new red mixture stuff is just one step above oil. And that's great. I've been using it for at least 15 years now. Good stuff and I really like it.

All EP greases use a disulfide. Molybdenum is the main one. It is essentially made up of microscopic plates that slide easily against each other and at the same time they stick to the metal. No matter how shiny, the surface of metal looks like the Rocky Mountains under an electron microscope. So some plates stick to the rough metal. Other plates come along and slide over those plates. It's a great system.

Graphite is the original plate type material and is usually mixed in as well. Lithium type soap for the thickner is used for the same reason. It replaces the basically useless regular soap with a plate material for even more sliding. And the old type soap wears out before the oil gives up.

The EP trade off is that for open bearings the lithium type soap base isn't as tolerant of temperatures and mechanical activity as regular old style grease. The oil part just wants to ooze out. They don't use as much soap and the oil is just on the verge of escaping at all times. It must be kept captive for remix by mechanical means.

Oil stays trapped in the old style soap better. Better chemical bonds. Old school wheel bearing grease has molybdenum disulfide (or graphite, or both) in it to increase pressure handling (just like the new stuff), but also has extra thickeners to make it stay in place and be extra sticky at the same time. And for most things it's all you need.

You can mix your own oil using moly and graphite and have some whizzy stuff, but it tends to separate out some when mixed heavy.

Valvoline has always made a good product as far as I'm concerned. Good lifespan and engines come apart as clean as they left the factory.

My two bits.

Three brands that do not "melt"
Marfax #2
Mobile Synthetic tube grease (wheel bearing use on label)
Ford spec Chassis and wheel Bearing grease (also in a tube)
Jim

Bearings are tightened and then backed off one castlelation. The grease ran out in the 5 days it sat in the shop since I regreased them. Hadn't even driven it yet.

Are any of these fairly tacky? I like to use the tackiest grease I can find in all the bushings around the farm. Thanks

Thanks for the info! Do you know where I might be able to find fiber grease? My grandfather used to talk about it. I think it would stay in older bushings well. So maybe if I don't need to do disc brakes, don't buy EP grease? Thanks!

(quoted from post at 21:26:27 05/03/10) Bearings are tightened and then backed off one castlelation. The grease ran out in the 5 days it sat in the shop since I regreased them. Hadn't even driven it yet.

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Are completely drying those bearings and the inside of the hub before you repack with new grease? Is the grease turning to liquid and running out, or is it just being squeezed out because you packed too much in there?

I installed new wheel bearing in an H 2 weeks ago. I packed them with the red EP grease, and in the 2 weeks, not one drop has oozed out or dripped out.

All are, with Marfax being a fiber (very stringy) tub (not tube) grease) Jim

(quoted from post at 05:26:32 05/04/10)
I installed new wheel bearing in an H 2 weeks ago. I packed them with the red EP grease, and in the 2 weeks, not one drop has oozed out or dripped out.

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I'd venture to say you have better seals. 8)

I have one tub of red stuff that (in the summer) will slowly pool oil on the surface just setting there. I suppose it just depends on the vagaries of the mix. One of the pluses to the old thick stuff is it helps form a barrier, supplanting the MIA seal lips. Not a great idea, but it is what it is.

I did add grease fittings and zerk caps to the hubs and pumped them full after packing them on the bench. However it is extreme pressure grease, you would think it would take the pressure from a hand operated grease gun. lol. Yes, the hubs and beaings are always well dried when I've had to flush them out with solvent. I noticed in the tub of grease before I used it, that there was a small puddle of oil in the lowest point. I've seen that before, but not that much. There was no oil spilled in the grease.

Where did you manage to find fiber grease? Thanks!

Pumping them may be a problem... Even small guns can make tremendous pressure, and pop or crack seals. It's a problem with track rollers on crawlers. Lever guns typically make 5000 PSI, you can get them to 10,000.

I pulled out my grease gun the other day that hadn't been used since last fall. Had a tube of that red Marvel grease, a good grade of grease. Pumped and nothing came out. Pulled on the handle and it dribbled red oil all over the place. Threw out what little was left in the tube. It's bad when you can't trust gun grease either.