Grease Compostion of Sealed Units

[outrun]

One source says the grease contained in sealed units (ball joints, tie rods, etc) contains "special chemicals" that allow the lubricant to survive long intervals.

So my question is this ... are these chemicals simply a different additive package over standard servicing grease charges?

Is the grease in a sealed unit superior to most over the counter grease charges? In other words if you could procure this grease type (assuming it is special) would there be any advantage to using it to service a greasable components.

 

[Eddie]

Very high moly content for CV joints.

 

[MolaKule]

That's a good question and what I have seen is polyurea and other thickeners with synthetic bases and extra antioxidants, AW, and rust inhibitors, but no "special" chemicals.

Keep in mind that sealed units like ball joints, tie rods and such are in sealed environments so no outside contamination can enter.

Now sealed bearings are another issue, and some pretty exotic stuff goes into those greases, especially the ones for aerospace.

 

[salesrep]

I do not think that there are any "special chemicals" in sealed bearings for the auto market above and beyond perhaps just a good grease. Most guys in the truck world replace the sealed bearings with greasable ones because they last longer than the sealed oem ones.
Not to mention the fact that we would be talking about additional dollars the oem would have to spend.

 

[Kestas]

Our company makes sealed bearings, including non-serviceable hub units. Nothing special goes into them. In fact, we are amazed at how cheap and bland some of the greases are used in OEM hub units (but they do have EP additive and are resistant to high temp). Our tech staff would rather see some premium greases used in manufacture, such as Mobil 1 or Infinitec. But we find as long as the seals do their job, the grease will do its job.

Our sealed truck hubs rated for one million miles use Mobil 1.

 

[SamSpade]

What is an appropriate grease to use for a sealed engine belt tensioner pulley like the one below? The bearing didn't wobble but was already free-wheeling. I removed the seal and found very little grease left inside to lubricate the ball bearings. Not knowing anything about grease a few months back, I packed it with NLGI #2 and replaced the seal. It didn't last and apparently centrifuged out the seals.

 

[OVERKILL]

Normally, you just replace the whole bearing.... They are quite inexpensive.

 

[SamSpade]

Problem is it's for a mechanical belt tensioner on a BMW. There's no part number for the pulley and can only get it by ordering the whole ten$ioner. Strange I know.

 

[OVERKILL]

There should be a part # on the bearing though, kinda looks like a generic SK-style bearing. We recently pressed-out and replaced the one on my sister's Explorer, which was making a lot of noise.

 

[SamSpade]

Oh if you meant replacing the bearing only and not the whole pulley, it's been difficult to find that bearing size: 17 x 40 x 14.

These are the marking on the bearing:
NBR+FE, BRS, 06-527, 06-462, 003-814-149/372

It's made by INA-[censored] but I can't find any of those numbers in their online catalog.

 

[OVERKILL]

Can you find the part # on it?

 

[1 FMF]

Originally Posted By: SamSpade
What is an appropriate grease to use for a sealed engine belt tensioner pulley like the one below? The bearing didn't wobble but was already free-wheeling. I removed the seal and found very little grease left inside to lubricate the ball bearings. Not knowing anything about grease a few months back, I packed it with NLGI #2 and replaced the seal. It didn't last and apparently centrifuged out the seals.


i thought polyurea grease was most used in sealed for life applications.
maybe try lucas xtra heavy duty polyurea grease.

 

[Kestas]

Originally Posted By: SamSpade
... I removed the seal and found very little grease left inside to lubricate the ball bearings...

Your problem isn't so much the type of grease as it is a seal (technically, "grease purge") issue. Find why the grease left the bearing and you'll solve your lubrication problem.

The closest thing I could find in the SKF book for deep groove ball bearing is 17 x 40 x 16 (ID x OD x width). It's always that way with automotive - they like to use non-standard parts.

 

[tom slick]

Chevron SRI claims to be an OEM fill for sealed bearings. It's polyurea based.