I have a customer with a Terex RH 340 Excavator on an open pit site (brand New Terex). The call out is for a lithium based 3% moly grease for the excavator arm system. The grease in question utilizes a "Fine" moly at 3.3 micron. The system requires a screen and filter to make sure the grease is clean when it goes into the auto lube resvoir. The screen is a 70 mesh, with a 200 micron filter. After a months operation the screen(s) began to clog after a few days operation of filling the resevoir. The residue is the lithium soap and the moly combined. A small amount of oil and soap product gets by but not close to what it was. After solvent cleaning the system is only good for another few days. A far cry from what it was in the begining. Is the Moly plating out onto the screen and blinding it? and not being affected by the solvent cleaning? I wasn't aware moly could do that. The grease is a Red-I contractors grease from LSC in Los Angeles, NLGI 2. Any thoughts on this?

First off I would recommend that they not use an EP2 in any autolube system. It is classified as a wheel and chassis lube that stays where you put it. See if the product is available in an EP1 as that has better flow characteristics. The problem you are experiencing may actually be seperation, where the base oil is being squeased out of the thickener. This is more common in Injector style systems where the lubricant is under pressure, then vents and this cycle makes the situation worse.

Some other greases also have graphite in place of the moly as it is cheaper and they call it moly. This also seperates easier as well.

Also see what pressure the system is running at, if the pressure switch is set to high, it may be holding the pressure to long squeasing the oil out further.

Another thought is that because of your location you may have a problem getting an EP1 from that supplier. You may have to look for it with a larger manufacturer.

I would also recommend going to a lighter grease in a auto lubrication system. Many auto lube systems spec a NGLI# 0 or 00, I would check the lube system manufacturers data sheet on the unit to verify that you are using the correct NGLI# grease.

Yes gentlemen this is the spec as indicated by the manufacturer. I didn't agree with it from the beginning. They are of course in Europe, and according to my customer, are not very responsive to this problem. On top of that, they call out no solids larger than 3 mu, and then spec moly 3. which is if course a median size moly solid, meaning plus or minus 3mu in the grease. For a piece of equipment as large as most apartment buildings, and you pretty much have to own a gold mine to buy one, this seems to be pretty poor support on their part.
As the equipment is under warranty, the customer is hesitant to modify any factory call outs. Hopefully he is insured for lack of revenue when the equipment goes down. I have recommended an EP1, and as LSC in L.A. manufactures most of the grease for the major oil companies on the west coast there will be no problem getting the product if the customer so desires. Hopefully he will desire, and solve the situation (maybe).
We are aware of the "Squeezing" factor regarding the oil within the grease from experiences at steel mills in the area. However this does not appear to be the case here. The residue on the screen, and the product that does get through appears to have the full compliment of lubricant held within the soap.
Another minesite is useing the same piece of equipment and 76 megalith moly grease with no problem. We manufactured the grease we are useing to the exact specifications of that 76 grease and it will not work. Leading us to believe the opertaional piece of equipment has been modified. No information on that modification is forthcoming.
Having a great time in California, wish you were here!

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Hello I have another option i think might be worth looking into I've seen similar things on P&E mining equipment similar to yours. The moly grease was leathering as they call due to the pressure it was under and it hardened up some and seperation was occuring screens and things were clogging like you described. The problem child as it was called was taken care of by a overbased calcium sulfonate grease that protected everything better that the the moly and without the metals that plate but "Calcite Particles" The grease was ground finer a #2 grease as well. It eliminated the clogging as well as some very expensive problems with downtime in other applications. getting so much better protection in every area over the moly greases. It also replaced 3 different greases and gave better performance. we were amazed theres a link to there grease page in the attachment. Hope this helps good luck hawk

Hi Odie.

I;d like to look into that, looks promising. But thre wssn't a link attached attached. Can you send it direct to me?
petrohawk@gmail.com.

Thanks
Hawk

quote:

Originally posted by odie19822003:
Hello I have another option i think might be worth looking into I've seen similar things on P&E mining equipment similar to yours. The moly grease was leathering as they call due to the pressure it was under and it hardened up some and seperation was occuring screens and things were clogging like you described. The problem child as it was called was taken care of by a overbased calcium sulfonate grease that protected everything better that the the moly and without the metals that plate but "Calcite Particles" The grease was ground finer a #2 grease as well. It eliminated the clogging as well as some very expensive problems with downtime in other applications. getting so much better protection in every area over the moly greases. It also replaced 3 different greases and gave better performance. we were amazed theres a link to there grease page in the attachment. Hope this helps good luck hawk

Gentlemen,
Thank you for all of your excellent advice and help.
What happened, it would appear, is that grease we supplied had too much "Tackifier" in the mix. As you know "Tacky" is not the word to use with regards to a centralized lube system. Tends to slow things down to say the least. Tacky plus EP2 REALLY slowed things down.
So we have now applied a grease that has no tackifier, but is still an EP2 with of course 3% moly.
Have to wait and see what happens. I realize that this is not the best way to approach a problem, "Wait and see" however in this instance I have no choice. I'll keep you updated on the situation.

Hawk if you are makeing this grease buy cold milling in tack and moly it will be lumpy.

are you the Mfg? from scratch? or adding to a stock grease?

sounds like NO tack and fully mixing will solve the poblem.

A good qaulity 3% moly grease should have NO problems in your system.
bruce

Bruce,

No, we are using Lubricating Specialities Co. as the Mfg. They are the major supplier on the west coast for product. They mix most of the majors product for them.
We manufactured the product to the customers specs, namely 76 Megaplex XD3. Another Terex excavator seems to be using that product succesfully.
However, calling Tech at 76 I find they do not recommend this grease in a central lube system. Even the winter grade NLGI1 is not recommended. Too "Tacky".
So, my rec. is 3% moly, Lithium Complex, EP, NLGI 1, No tack. That should fly. Let you know what happens.

sounds good to me I use metalcote/chemtool
bruce