U joint grease

[lt1fire]

What is the best U joint grease that you can buy at napa, auto zone, etc.....
I know that the green stuff is good from going through some old posts but I just want some stuff that I can walk into the store today and get.

Thanks
Al

 

[e9999]

don't know the answer to your question based on facts, but I'll say that this is not not high on my worries scale. I'm guessing that the number of Ujoints failing because of less than superior grease is insignificant compared to the number failing because of insufficient grease altogether. IOW, more frequent greasing with so so grease (assuming we can even figure out which is better) is probably better than infrequent greasing with that miracle grease somebody has vaguely heard of.
I'll just put in what I have in the gun at the time, which is usually Moly and can still live with myself.

 

[Cruiserdrew]

What ever grease you have in the gun is fine. Just remember to do it every oil change and after each time you are in water over the hubs. I think Moly grease is slightly preferred, but any wheel bearing type grease will work. I've used the Amsoil with moly for years at the recommendation of Slee inc. That's the only Amsoil product I use, but it seems to be good.

 

[98 SNAKE EATER]

From what I've read, moly will cause small needlbearings to slip instead of roll, causing premature wear and eventually cup failure

Should be fine for larger roller bearings, but I'd rather not take a chance on my u-joints

I use Valvoline Multi-Purpose bearing grease (Red) for U-Joints and Valvoline Palladium 3% moly for birfs and yokes (but they rarely need any)

Separate guns for each of course

BTW, I'm a firm believer in over greasing when it comes to U-joints

I don't stop pumping until I see all of the old grease pushed out of each cup and replaced with fresh red

I do it at every oil change (about every 3 weeks) and you'd be surprised how dark red grease gets after just 3000 miles of use

 

[lt1fire]

I tried doing this today and it didn't seem like any grease was going in. It just seemed it was comming out gun and right past the zerk.

 

[Tools R Us]

From what I've read, moly will cause small needlbearings to slip instead of roll, causing premature wear and eventually cup failure ...

If there were so little friction that the needles don't roll, how would they wear? I know a bunch that use moly in u-joins without issue, too messy for me.

I prefer thick, stay in place type grease for u-joints, agricultural shaft or heavy equipment greases work very well. They are waterproof, anti-sling, take a big pounding type grease, but for most aren't easy to find. Right mow I'm using Valvoline DuraBlend, it's working well. Tried Mobil synthetic, sling out very quickly, was greasing constantly.

 

[91Cruizer]

Would marine style grease be any better than regular?

 

[cruiserdan]

My LANL (Los Alamos National Labratory) geek scientist friend says that molly grease is not suitable for high-speed bearings because the rollers tend to skid as opposed to roll.

He builds really spendy bomb parts for a living and I tend to belive him.

 

[Tools R Us]

My LANL (Los Alamos National Labratory) geek scientist friend says that molly grease is not suitable for high-speed bearings because the rollers tend to skid as opposed to roll.

He builds bomb parts for a living and I tend to belive him.

I have heard that from several sources, including a Harley engineer. He also said you cant run synthetic oil in Harley motors for the same reason. Then Harley came out with their own synthetic oil and he changed it to, it's only permissible to run Harley oil, it has a friction modifier to make the bearings roll.

Talking to buddies who are mechanical engineers, one designs industrial air tools the other machining tools. Their first reply is, "if there were so little friction that the needles don't roll, how would they wear?" Followed by, high speed bearings need to be properly greased. Most only get about 15-20% of the void area filled, if packed they can overheat, rollers/balls fail to roll, etc, grease isn't the best lube for high speed bearings, oil is far superior, etc. But their definition of high speed is in the 20K-100K rpm.

When prodded to talk about automotive bearings; they turn at a fraction of their full rpm rating, most would be classed as slow speed bearings, so packing is acceptable. U-joints are very low speed bearings, they only turn a fraction of a turn (slight angle change) with each drive shaft rotation. Even with the 4-1 diff ratio their total rpm is slower than the birf, wheel bearings, etc. So thick or extreme pressure type greases would not be a problem, totally unnecessary, but wont cause any issues.

 

[lt1fire]

Anyone know why my grease didn't want to go into the zerks??

 

[scottm]

Anyone know why my grease didn't want to go into the zerks??

Sometimes you have to press the grease gun on hard to keep a seal. The grease inside may be a bit dried out. If it's a bearing fitting it should have a hex on it so you can unscrew it. The zerk inside the yoke is for the slip joint, and that is pressed in, I don't know if there's room to pull it out with the joint assembled.

 

[scottm]

Talking to buddies who are mechanical engineers, one designs industrial air tools the other machining tools. Their first reply is, "if there were so little friction that the needles don't roll, how would they wear?"

Typical engineering assumption of a perfect world. In reality, there are imperfections and bits of debris that can make a roller or ball stop momentarily. If it stalls long enough it can wear a slight flat spot, which keeps it from rolling and makes adjacent rollers carry more weight, leading to further failures. Less slippery lube will give the rollers enough drive to crush or push the debris away. The grease has other functions like absorbing and transferring heat.

 

[jvazquez53]

My LANL (Los Alamos National Labratory) geek scientist friend says that molly grease is not suitable for high-speed bearings because the rollers tend to skid as opposed to roll.

He builds really spendy bomb parts for a living and I tend to belive him.

Bomb building guys rock! I would believe him too!! I use on mine Slick 50 grease.

 

[scottm]

Oh, and most oils and greases like Mobil 1 have moly in them these days. It's an inexpensive way for manufacturers to meet test specs, so they do it.

 

[livinoffroad]

Good discussion here.

I was a "grease monkey" when I was a kid for a while, when I apprenticed in the Operating Engineers in the Bay Area.

Y'know...runnin the grease truck, with all the diesel, and hose reels of different types of grease across the back.

We used to hit the lines of 20-50 pieces of construction equipment, after they worked all day in the hot sun building huge housing tracts back in the '70s.

Uh Oh, I'm waxing nostalgic...must be gettin' old.

There are a lot of very knowlegable people here, concerning grease, and I know only a little.

Grease is basically oil and soap, mixed together. It is dyed different colors only for identification.

It is affected by heat, (pressure, friction) thus the different heat ranges, "suitable for high speed bearings", and oxidation.

Oxidation is what makes it plug your zerks, the oil basically evaporates from the grease, leaving the soap.

Folks here are right, frequent greasing is the best care for U-joints. We greased our construction rigs DAILY.

A nice cheap name brand NLGI #2 (recommended by FSM) is available at your local auto parts store on sale for $2 a tube.

I keep #2 in one gun (marked #2) with a felt pen, and molybdenum based grease in another (marked moly).

Everyone here is right, moly causes sliding, which is good for sliding joints like the birfield.

Here's a fun test for you pyros out there...put some #2 grease in a tin can, or other non-combustible container.

Now take your torch, and burn away the oil in it. What you should have left is melted soap, which will cool and congeal into the familiar feeling product we use daily (most of us);p

Just my $.02

 

[nicholas]

Sometimes you have to press the grease gun on hard to keep a seal. The grease inside may be a bit dried out. If it's a bearing fitting it should have a hex on it so you can unscrew it. The zerk inside the yoke is for the slip joint, and that is pressed in, I don't know if there's room to pull it out with the joint assembled.

I have a hard time getting grease in mine too. Are you saying I have to replace the nipples with new ones? Maybe I'll try to get the ball valve mobile with some PB blaster.

 

[scottm]

I have a hard time getting grease in mine too. Are you saying I have to replace the nipples with new ones? Maybe I'll try to get the ball valve mobile with some PB blaster.

Shouldn't need to replace them, but you can get in behind them and see if grease has congealed in there.

 

[scottm]

Grease is basically oil and soap, mixed together. It is dyed different colors only for identification.

Yep, lithium soap is what thickens oil into grease. Lithium is a soft metal. Grease liquifies (drops) at about 180C, the melting temp of lithium. I use Mr Moly grease, it's thickened with clay, giving it a crazy high drop temp.

It is a good point about the soap clogging zerks, I wonder if my clay thickener might leave my zerks plugged worse?

 

[98 SNAKE EATER]

If there were so little friction that the needles don't roll, how would they wear?

I couldn't tell you why as I'm not an oil expert nor a bomb builder, but just going by what I've read here, I'd rather not chance it on sumthin as critical as a U-Joint

 

[livinoffroad]

"It is a good point about the soap clogging zerks"...



If the oil doesn't "evaporate" from the soap...then it will "migrate" from the soap, or clay, or whatever emulsifier is used.

Principle being, that oil doesn't like to STAY mixed with ANYTHING.

Therefore, the operative word to use here is "frequent" greasing.

Frequent is relative, so I can't say what's right for you, (once a month is good for our lifted rigs) but it is as easy as rolling your floor jack under an axle, (yes, and block it up) and puttin' your shifter in neutral, then turn your drive shaft for the best angle of exposure.

Usually don't have to remove a plugged zerk, unless the face is dinged. Just apply steady pressure for some 30-60 seconds with the head locked on well, so it doesn't leak, and the grease will usually start to flow. Just remember to get back there soon, and it won't dry up on you next time.

Frequent greasing will eliminate plugged zerks...mine flow nice and free AND, as an added plus, while you're under there, you can look around and see if rocks or branches have torn anything loose, if there are any new leaks (check that steering pump, speedo cable, felt seals behind the birfields, etc. from there), and how much play your U-joints have when you line 'em up to grease 'em.