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Hello all - I am planning to re-grease the worm gears on my G11 (which I purchased from new in 2009).?

I have seen a few websites where this is described, and on one I saw that someone had put grease all around the outside of the large worm wheel.?
I worked in the lubricants industry for almost 30 years, and I would have thought you only need to lubricate the worm.
The contact between the worm and the worm gear is what is known as an elastohydrodynamic contact - in practice the oil film thickness between the gear teeth will be less than 1 micron (in fact much less if the gears are heavily loaded).?
So let's say you put 5 ml of grease on the worm. That will be more than sufficient to coat all the worm wheel during operation.?
Do people generally think it necessary to grease the worm wheel? I would have thought this would be far too much grease and if it leaks into other parts of the mount (like the clutches) it could cause problems.

Synthetic grease would be a good choice, since this will definitely reduce friction (even if the synthetic and mineral grease seem to have the same viscosity at room temperature and pressure, the viscosity of the synthetic lubricant will be lower than that of the mineral oil when it is at the high pressure in the gears).?

Finally, do you have to dissamble the worm to regrease it? I would have thought you could use a toothbrush soaked in degreaser pressed against the worm when it is rotating at 16x (with no load on the mount) to remove the old grease, and then just apply a small amount of new grease on the worm. Do people think this would work OK?

Robert.Ian:

You know I just did this about a month ago and I did a full disassembly. I really wanted to get rid of the old lube and also any metal fines that accumulated when any two metal parts move against each other. Plus I had lube leakage into the clutches from the hot summer weather. If you ever have changed the oil on a new car, you may know the first drain is full of metal debris you don't want inside the engine. So I cleaned all the working parts with solvent and a brush, first gasoline then a final rinse with Brakleen.?

Reassembly went well but I would have to advise that the final tuning of the worm blocks was time consuming and bit tricky. I would suggest viewing the Losmandy videos on this before trying anything. I am pretty mechanically inclined and have a master mechanics tool set and a pretty complete workshop, but the first time around for me was a bit involved. You need to pressure the worm inward and to the left to mate the worm and ring gears, and then back off just right with the adjustment screw to stop the motor from stalling. Leftward pressure closes the gaps between the blocks and reduces sideways motion. When Losmandy says they don't recommend this at home I can see why. It takes some experience to get it just right. Too loose and you have backlash, too tight and you stall. And the margin for error in between is quite small. You probably should do a PE analysis with PEMPro or PECPrep before any work to make sure you get back to the same PE you started with.

I used the Teflon based Superlube, which is temperature resistant, and did a light coating around the whole ring gear and the worm too. The light hydrodynamic film should serve to ride over surface asperities and reduce any minor chatters. But the Teflon also serves as a barrier film to further separate higher pressure contacts. Losmandy uses that Jet-Lube MP-50 with molybdenum, which is probably overkill, but may serve to chemically react with the wear surfaces as an extreme pressure additive.? ?

So a full disassembly is best for lubrication, but you may be in for a chore to retune the worm blocks if you remove the worm to do a deep clean.

Good luck,

John

I agree with John Kmetz: full disassembly.? In addition to getting all the old lubricant and grit out and adjusting the worm mesh on reassembly there is also the opportunity to degrease the clutch pads.? The grease eventually migrates everywhere.? SuperLube is the default recommendation of many on Cloudy Nights.