polyurea grease compatibility

[neo3]

I got a tube of John Deere polyurea grease, part #TY6341, for greasing control arm ball joints. I used a lithium/moly type grease on them previously. Now I find that there's a difference between "shear stable" polyurea grease and "conventional" polyurea grease, where the shear stable type is compatible with lithium grease and the other type isn't. See: www.machinerylubrication.com/Read/1865/grease-compatibility (Found this out from an older posting on here.) The problem is I can't find any explanation for how to know which type of polyurea grease I have. Anyone know about this? There's no way to clean the old grease out of the control arm joints. I'd like to use the grease I already got if it will work.

 

[neo3]

Update - I couldn't find a real data sheet, but the John Deere product blurb says it's compatible with "most" other greases, so I'll take that to mean it will be OK with lithium type grease.

 

[tundraotto]

Literally a sticky on the top of this very sub-forum.... https://www.bobistheoilguy.com/foru...compatibility-chart-and-info#Post5293259

 

[bchannell]

Yeah, and if you read JD literature, it states that it is shear stable PU grease. If you do a search you'll find the literature.

 

[ABN_CBT_ENGR]

Originally Posted by neo3

Update - I couldn't find a real data sheet, but the John Deere product blurb says it's compatible with "most" other greases, so I'll take that to mean it will be OK with lithium type grease.

You will probably be fine in your application but don't let that word "compatible" scare you or give you a false sense of security- all it means is that the components in question ( not the grease compound as a whole) will not have an immediate adverse reaction. Compatible does not mean they will maintain the same properties, carry the same loads or wont attack each other and change critical properties across the spectrum. Its always best to clean out and replace as much as possible when switching greases. Even if it means a few extra purge cycles. PU greases generally perform acceptably for low to medium boundary applications such as yours

 

[eyeofthetiger]

I have found myself using a polyurea grease (Lucas X-tra Heavy Duty) on brake caliper guide pins when I didn't have my preferred silicone grease on hand. It is listed as shear stable, extreme pressure, waterproof, with a 560°F drop point (I realize Lucas puts all kinds of marketing junk on their packaging, but some of it has to be true). I am assuming the polyurea base should be fine with rubber or EPDM parts. The high compatibility means it should be okay with some of the unknown grease residue left in the bore. I'd like to hear any opinions on using polyurea for this application, because I've never heard of anyone else doing it.

 

[ABN_CBT_ENGR]

Originally Posted by eyeofthetiger

I have found myself using a polyurea grease (Lucas X-tra Heavy Duty) on brake caliper guide pins when I didn't have my preferred silicone grease on hand. It is listed as shear stable, extreme pressure, waterproof, with a 560°F drop point (I realize Lucas puts all kinds of marketing junk on their packaging, but some of it has to be true). I am assuming the polyurea base should be fine with rubber or EPDM parts. The high compatibility means it should be okay with some of the unknown grease residue left in the bore. I'd like to hear any opinions on using polyurea for this application, because I've never heard of anyone else doing it.

First, the base oil (not the PU thickener) and any seal agents in the recipe will determine suitability for rubber/EPDM concerns. Otherwise, you should be perfectly fine in your application even with some residue.

 

[eyeofthetiger]

Originally Posted by ABN_CBT_ENGR

Originally Posted by eyeofthetiger

I have found myself using a polyurea grease (Lucas X-tra Heavy Duty) on brake caliper guide pins when I didn't have my preferred silicone grease on hand. It is listed as shear stable, extreme pressure, waterproof, with a 560°F drop point (I realize Lucas puts all kinds of marketing junk on their packaging, but some of it has to be true). I am assuming the polyurea base should be fine with rubber or EPDM parts. The high compatibility means it should be okay with some of the unknown grease residue left in the bore. I'd like to hear any opinions on using polyurea for this application, because I've never heard of anyone else doing it.

First, the base oil (not the PU thickener) and any seal agents in the recipe will determine suitability for rubber/EPDM concerns. Otherwise, you should be perfectly fine in your application even with some residue.

Forgive my grease illiteracy. It is supposed to be a synthetic grease, but the MSDS doesn't have any information about what is actually in it.

 

[ABN_CBT_ENGR]

Originally Posted by eyeofthetiger

Forgive my grease illiteracy. It is supposed to be a synthetic grease, but the MSDS doesn't have any information about what is actually in it.

Synthetic just means something in it has been modified ( that's a whole different subject for Pandora) The SDS most likely wont help- you need the product data sheet and specifications. I would be surprised if a company like Lucas would make and market something that would have adverse affect on an automotive standard polymer but it never hurts to ask. You will be fine in your application for this, I'm sure