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How to free stuck worm rings? (dried grease)

 

Hello all -

I recently joined the group, having just purchased a G11 earlier this week, and converted it to OnStep.? The seller claimed the mount was "tested" and in "great condition" aside from the missing gemini controller.? As soon as I got home, I immediately noticed the DEC would not move at all, even with the clutch fully removed.?? I had to use a long piece of scrap lumber clamped down in order to get the dec to turn a few degrees.? I spent a few hours with various solvents and a rubber mallet until I finally was able to tap the dec shaft out of the housing.? The roller bearings were completely caked with dried old grease that had turned to varnish.? I was able to clean the upper roller bearing fairly easily, but the lower roller bearing required soaking in lacquer thinner overnight.? The next morning, after a couple more hours of fiddling, I was able to free up the lower bearing.? While I was in there, I wanted to clean up? the thrust bearing under the worm wheel, however I could not get the worm wheel off of the black anodized hub part.? Luckily the thrust bearing appears to spin freely, however I do worry the grease may be caked on like everywhere else.? I tried some gentle tapping to the hub using a PVC fitting to avoid damage.? I also tried mild heat from a hair dryer.? And of course, I tried pulling it off with my bare hands. I cant get it to budge.? I don't want to try any mechanical leverage for fear of damaging the worm wheel.? Any suggestions on getting this thing loosened up?

For what its worth, the rest of the mount was in really nice shape.? The whole RA side looked to have been freshly serviced. I've already swapped out the worm bearings, cleaned and re-greased the shaft roller bearings and worm wheels with superlube. The dec thrust bearing is the only part I can't get to. ? Anything else I should check or address?? I believe the mount is a 2009 model judging by the serial number.? Two piece worm blocks, HP brass worms, single D style saddle, etc.

Thanks for any suggestions,
-Tony
 

Hi Tony,

From my recollection, the GM8 size worm wheel won't come off (your DEC axis) until you remove the DEC worm. With the worm in place it's threads hold the worm wheel in place.? Possibly your worm is jammed into the ring gear...but maybe not.??

Take the DEC worm out and then start to take off the DEC ring gear.? Under the worm wheel (aka ring gear) you should find that the flat needle "thrust" bearing has a thick race washer above the needle bearing and a thin race washer below the needle bearing.? That is the correct order.? Look also for the common problem of oils coating one or both of the plastic clutch disk surfaces.? ?Clean those surfaces well.??

See attached docs for a few more ideas.

Have fun,
Michael

On Sat, May 1, 2021, 6:45 AM GuitsBoy <guitsboy@...> wrote:
Hello all -

I recently joined the group, having just purchased a G11 earlier this
week, and converted it to OnStep.? The seller claimed the mount was
"tested" and in "great condition" aside from the missing gemini
controller.? As soon as I got home, I immediately noticed the DEC would
not move at all, even with the clutch fully removed.?? I had to use a
long piece of scrap lumber clamped down in order to get the dec to turn
a few degrees.? I spent a few hours with various solvents and a rubber
mallet until I finally was able to tap the dec shaft out of the
housing.? The roller bearings were completely caked with dried old
grease that had turned to varnish.? I was able to clean the upper roller
bearing fairly easily, but the lower roller bearing required soaking in
lacquer thinner overnight.? The next morning, after a couple more hours
of fiddling, I was able to free up the lower bearing.? While I was in
there, I wanted to clean up? the thrust bearing under the worm wheel,
however I could not get the worm wheel off of the black anodized hub
part.? Luckily the thrust bearing appears to spin freely, however I do
worry the grease may be caked on like everywhere else.? I tried some
gentle tapping to the hub using a PVC fitting to avoid damage.? I also
tried mild heat from a hair dryer.? And of course, I tried pulling it
off with my bare hands. I cant get it to budge.? I don't want to try any
mechanical leverage for fear of damaging the worm wheel.? Any
suggestions on getting this thing loosened up?

For what its worth, the rest of the mount was in really nice shape.? The
whole RA side looked to have been freshly serviced. I've already swapped
out the worm bearings, cleaned and re-greased the shaft roller bearings
and worm wheels with superlube. The dec thrust bearing is the only part
I can't get to. ? Anything else I should check or address?? I believe
the mount is a 2009 model judging by the serial number.? Two piece worm
blocks, HP brass worms, single D style saddle, etc.

Thanks for any suggestions,
-Tony
 

Hi Michael, thanks for the response.? The mount in question is actually the G11, not the G8, however your description sounds correct.? I did have the worm and worm blocks out at the time, and had already removed the DEC shaft and clutches.? Assuming it is not a press fit, the worm wheel is not being mechanically held on in any way.? I believe its simply dried grease that has solidified, keeping the worm wheel from sliding off and exposing the thrust bearings.? Ive hit it with a few solvents and penetrating oils, but it didnt let loose.? Since the thrust bearing is still spinning OK, I decided to put the mount back together for now and tear it back down next long spell of inclement weather.

Thank you for your paper on installing the belville washer.? I've been doing some reading on this for a while, but have not yet done the mod.? For now, its still the stock two piece worm configuration, but with new abec-5 bearings pressed in (snug fit, no slipping).? Since the mount is new to me, I want to get a baseline first.??

Thanks again,?
-Tony
 

No problem, Tony.
If you only need a couple of the R4 Belleville washers, I have some at home that I supply to our group.? Let me know.

You can also give me a call if you want to?discuss optimizing these mounts.? My phone number is usually in my PDFs.? A picture is worth a thousand?words, and a phone call can be worth a thousand pictures.?

All the best,
Michael




On Sat, May 1, 2021, 9:48 AM GuitsBoy <guitsboy@...> wrote:

Hi Michael, thanks for the response.? The mount in question is actually the G11, not the G8, however your description sounds correct.? I did have the worm and worm blocks out at the time, and had already removed the DEC shaft and clutches.? Assuming it is not a press fit, the worm wheel is not being mechanically held on in any way.? I believe its simply dried grease that has solidified, keeping the worm wheel from sliding off and exposing the thrust bearings.? Ive hit it with a few solvents and penetrating oils, but it didnt let loose.? Since the thrust bearing is still spinning OK, I decided to put the mount back together for now and tear it back down next long spell of inclement weather.

Thank you for your paper on installing the belville washer.? I've been doing some reading on this for a while, but have not yet done the mod.? For now, its still the stock two piece worm configuration, but with new abec-5 bearings pressed in (snug fit, no slipping).? Since the mount is new to me, I want to get a baseline first.??

Thanks again,?
-Tony
Keith
 

Michael:

Not to drift too far off topic, but why would the ordering of the main gear thrust washers matter, unless your G11 is different than mine (which looks the same as in this photo:??).

Keith
 

I had a similar situation with a 20 year old G11 I bought w/o controller.

To get the worm wheel off I had to put a couple of wood shims between the wheel and the mount. Tap with a rubber mallet on the end of each shim to drive the force up on the wheel. Keep moving the pair of shims around the wheel until it comes up enough to take it off the bearings.

Greg
 

Michael, Thank you for the kind offer.? When I get to that point, I would love to take you up on it.? I do love to tinker.? I'm kind of intrigued by the various DIY SLW's that people have come up with, and have a few ideas of my own as well. But for now, I'm just anxious to finally get this under the stars as it is.

Greg, Thank you for your advice. Funny you mention the shims, as I had actually used the plastic construction shims the same way.? However I was unwilling to apply much force for fear of ruining the worm wheel.? I mainly just added some tension as I tried to tap the center out with a mallet against a PVC fitting.? It didnt work.? ?Did you find you needed to use any solvents or penetrating oils?? I need to spend a bit more time on it, honestly.

Thanks again guys,?
-Tony

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