Isoflex topas 52 caking up

[NO HAND]

Hi, I've been using isoflex 52 in my Ski-Doo sealed crank bearings for years without too much complaints except the stuff is kind of drying out and clumping faster than I would like. I give the bearings a shot of isoflex about every 2k kms, or every 2 years. Now there is a well known crank rebuilder in my area that says there are equivalents other than Kluber for this stuff and they are mobilgrease 28 and aeroshell 22. He particularly recommended the mobilgrease 28 because he said it was softer and resists caking up and clumping like the isoflex does. What do you think?

 

[RDMgr]

I doubt that these greases are compatible. Isoflex is barium complex. Mobilgrease is clay. Aeroshell is "microgel" which may be silica or something similar.

 

[NO HAND]

So this would be an option only when cleaning out the old stuff, like after a crank rebuild.

 

[NO HAND]

I should have a chance to drop by his shop next week, I think he's been injecting the Mobil 28 one on top of isoflex for some time on the Ski-Doo cranks. I wonder what he thinks about compatibility. What is a sign of incompatibility?

 

[RDMgr]

The M28 and the Isoflex are likely not compatible. Further, clay thickeners are very sensitive to additives, most significantly metallic sulfonate rust inhibitors. It's difficult to predict what will happen with the majority grease being barium complex with the clay added. If it was the other way around I would expect the clay to degell. I recommend continuing with the same grease or cleaning the bearings before re-greasing with one of the others.

 

[NO HAND]

Thank you for taking the time to explain, I appreciate the explanation about the possible incompatibility. I couldn't ask as many questions as I wanted at my last visit to the crank rebuilder but I had a chance to wander in the shop and saw a crank with clearly two different layers of grease one was clearly the stock isoflex while the other layer was a red grease that I wish I could confirm if this was Mobil 28 or not. Poking with a piece of toothpick I could see both layers were relatively soft like it should but right where both greases would meet there was about 4 milimiters of hardened grease that was really too stiff. The hardened stuff was so rigid I could pull it out and it would hold itself together like a ring in the bearing cage. The isoflex at that place had turned to a pinkish color and I could tell both greases had turned equally to a harder unusable substance. I'm no scientific but one thing I can tell is I'm scared like heck to mix greases now. What I saw at least confirms you were right that compatibility is a big issue and not to take lightly.