What's in your balls? upper control arm joint cut open - Page 2 - PeachParts Mercedes-Benz Forum

nelbur · #16 12-03-2011, 01:44 PM

Quote:

Originally Posted by barry123400

In my opinion the old dried out grease was a barrier to fresh lubricant reaching the wear or contacting surfaces. That is why I like adding oil in a situation like yours.

Otherwise the oil component leaving the new grease slowly takes it's time softening up the old grease and allowing some of the oil component through to the surfaces. With a zerk fitting the new grease displaces the old enough to provide the lubricant to the surface much quicker if not instantly.

The other factor is the oil can be inserted using a small needle leaving a much smaller hole in the joints boot. Remember the original grease is stil in there in most cases and has just dried out and needs rejuvenation.

To understand the process drop a dab of grease on a piece of paper and leave it. You should see an increasing ring of leakage from the grease expanding with time outward as long as the grease can supply the oil. At some point the grease will have dried out and the ring will stop expanding.

This to me is the way grease really lubricates. We can buy all kinds of high pressure grease etc. Common sense is that with enough pressure it is squeezed out and will not flow back in with very high viscosity. Viscosity increases with the leakage of oil from the grease as well. So the oil component intrinsic to the grease bleeding out does the real job usually. Of course there will be spins on what I think.

I still feel like I might be viewed as a junkie when aquiring syringes and needles at the local drug stores. Especially by personel not knowing me well.

Sounds reasonable to me that oil from the grease was crawling up into the ball area. That would explain why it took so long to totally eliminate the squeak. I thought about adding gear oil, but I found the boot on this car to be apparently crimped in place when manufactured, so I could not pry the top out to pour oil in. I bought my grease injection needle from Auto Zone. The only problem you will run into is that the staff will never have heard of such an item, so you will have to find it yourself with the grease fittings, etc. I would guess that a genuine syringe would require a prescription from a doctor, but the odds are good that your doctor has a Mercedes, and would be sympathetic.

barry123400 · #17 12-03-2011, 07:10 PM

Quote:

Originally Posted by nelbur

Sounds reasonable to me that oil from the grease was crawling up into the ball area. That would explain why it took so long to totally eliminate the squeak. I thought about adding gear oil, but I found the boot on this car to be apparently crimped in place when manufactured, so I could not pry the top out to pour oil in. I bought my grease injection needle from Auto Zone. The only problem you will run into is that the staff will never have heard of such an item, so you will have to find it yourself with the grease fittings, etc. I would guess that a genuine syringe would require a prescription from a doctor, but the odds are good that your doctor has a Mercedes, and would be sympathetic.

Quite the contrary. Druggists have always sold or usually given me what I needed. You just have to be cautious around those sharp points.

I use them as well for fussy oiling or glueing applications on small items. My experience is that they are almost one use as what I fill them with seems to either seriously stick the rubber portion of the plunger or attack it.

Thats if left sitting unused for some period. For those applications I grind the sharp point off to blunt the end of the needle as well. If you flushed them out after each use they may last for many uses. Drug stores stock quite a few sizes as well.