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CPC Bearing replacement trouble

cassegrain SCT Celestron DIY mount
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10 replies to this topic

#1 AstroNP

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Posted 23 August 2019 - 10:49 AM

Hello everyone. I'm doing the bearing upgrade for my CPC 925.

https://www.google.c...c9RgHlb0com279W

But I've run into trouble. I can't get the clutch plate off. I've removed both set screws and the bolt in the center but it won't budge. It does twist a very small amount, left and right, so its lose, it just won't come up. Hoping someone can help. I've tried prying on it, I put a bit of lubricant in the holes to loosen it up, nothing. I can lift the entire scope+tripod by the clutch plate and it wont move.

#2 Point

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Posted 23 August 2019 - 12:17 PM

Wonder if any of these kind of bearing pullers would work? All kinds of shapes and sizes for reference here:

https://www.google.c...iw=1510&bih=931

 

 

Regards, Ron



#3 carolinaskies

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Posted 23 August 2019 - 08:31 PM

Loctite was used on that clutch likely.  If you have a hair dryer you can put it on it's hottest setting and try to heat the center of the clutch disk up to release the loctite. 



#4 AstroNP

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Posted 23 August 2019 - 09:04 PM

Hey guys, thanks for the suggestions. Fortunately I got it off and completed the upgrade without further issue. If anyone in the future has the same problem, I took a 3/8" allen key and used it pry up the clutch plate from the edges. Slowly move around the edge of the plate and eventually it will come off. Took a half hour but it worked.



#5 VinceV

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Posted 24 August 2019 - 06:32 AM

I needed to change out the nylon bearings a couple years ago because my CPC1100 wouldn't track or move on it's own (HC) at #1 or #2 speeds. Even though the stainless steel bearings were used, the primary source of my problem was due to the large center nut being too tight. Careful consideration was used when reinstalling with the correct amount of pressure and Loctite. It's been fine since.  



#6 Grant_SE US1234

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Posted 28 October 2019 - 07:27 PM

Hello everyone, I'm currently in the market and considering either a new CPC 925 GPS or CPC Deluxe HD 800. Would put the HD Wedge on either way and primarily use via camera/computer control for DSO's. I know a GEM would be better for tracking but am looking for something more user-friendly and already have a lot of accessories I could scavenge off my (now way over-weighted)  6se that I've had some success with on a wedge. I've read/seen the nylon bearing replacement article for the CPC 1100 on the NexStar Resource Site (written by VinceV perhaps?), and also noticed that the HD version is supposed to include both nylon and steel bearings. Can anyone confirm that a new CPC GPS still contains only nylon bearings? Thanks!



#7 Michael_Swanson

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Posted 28 October 2019 - 11:31 PM

According to the last info I received from Celestron (about 2 years ago), they did switch to a mixure of nylon and steel bearings on the standard CPC mount by that time.

 

The author of the bearing replacement article is Gary Bennett.  The article is found here:

https://www.nexstars...OddsEndsCPC.htm

 

Best regards,
Mike Swanson
Author of "The NexStar Users Guide II"
Author of "The NexStar Users Guide"
Author of "NexStar Observer List"
https://www.nexstarsite.com



#8 Grant_SE US1234

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Posted 29 October 2019 - 05:58 PM

Thanks Mike, that's great to hear! Great books and website by the way. Do you (or anyone else) know if this (upgrade to mixture of steel and nylon bearings) applies to both the newer 925 and 1100 (non-Deluxe HD)? I've heard that the mounts are identical except extra spacers for smaller OTA of the 925, but have also seen a lot more post about people upgrading the 1100 than the 925.

 

Thanks,

Grant



#9 Grant_SE US1234

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Posted 29 October 2019 - 06:04 PM

Hello everyone. I'm doing the bearing upgrade for my CPC 925.

https://www.google.c...c9RgHlb0com279W

But I've run into trouble. I can't get the clutch plate off. I've removed both set screws and the bolt in the center but it won't budge. It does twist a very small amount, left and right, so its lose, it just won't come up. Hoping someone can help. I've tried prying on it, I put a bit of lubricant in the holes to loosen it up, nothing. I can lift the entire scope+tripod by the clutch plate and it wont move.

I'm curious, how old is your CPC 925? Please see my posts above. Trying to confirm when/which models of the CPC began being made with both nylon and steel bearings (I know Mike said 2 years ago, but was curious about yours since it's a 925, the one I'm considering most). Also, do most people think the bearing issue is primarily due to wedge mounting? Thanks!



#10 Michael_Swanson

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Posted 30 October 2019 - 12:02 AM

Thanks Mike, that's great to hear! Great books and website by the way. Do you (or anyone else) know if this (upgrade to mixture of steel and nylon bearings) applies to both the newer 925 and 1100 (non-Deluxe HD)? I've heard that the mounts are identical except extra spacers for smaller OTA of the 925, but have also seen a lot more post about people upgrading the 1100 than the 925.

 

Thanks,

Grant

Thank you for the kind words Grant.

 

My understanding was the change was across all models in the standard (non-Deluxe HD) CPC line.

 

Best regards,
Mike Swanson
Author of "The NexStar Users Guide II"
Author of "The NexStar Users Guide"
Author of "NexStar Observer List"
https://www.nexstarsite.com


Edited by Michael_Swanson, 30 October 2019 - 12:03 AM.


#11 Grant_SE US1234

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Posted 30 October 2019 - 06:03 PM

Thanks Mike, much appreciated.




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