lens disassembly help

**wildlybored** · 07-12-2021, 11:37 AM

All
I have an old Korean made Sears 135 mm f2.8 telephoto lens 202.737370 with a stuck aperture. Have confirmed oil on the blades. Does anyone have step by step disassembly instructions?

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**niceshot** · 07-12-2021, 01:53 PM

Best bet is to remove the rear lens group and clean it from there. OR removing the grubs screws and twist off the front lens group. DO AT YOUR OWN PERIL. like I said go in from the back GOOD LUCK worked on this. lens a lot

**jon.partsch** · 07-12-2021, 02:02 PM

Hello and welcome to the forums!

I doubt you will find specific instructions for this lens, as I doubt it is a "classic" that many folks would be interested in using the time and effort to repair. Do you have experience with lens disassembly and service? Do you have the proper tools?

I will say that it should be a simple lens design and with some practice reconditioning lenses, you should be able to make the repair fairly easily.

I realize what I said above may note really help, but you can look on youtube for lens repair videos to see, in general, how old manual focus lenses are put together and what to expect when disassembling one.

I will caution you that the "partial disassembly and flush with lighter fluid" approach for dealing with oily apertures has never worked for me - the oil always comes back shortly. The only relaiable approach in my experience is a complete tear-down, cleaning, re-lubrication, and re-assembly.

**DWS1** · 07-12-2021, 05:59 PM

Even though most of these old manual focus lenses are different they are mostly made from very similar designs. So you may be able to figure things out from repair videos from several different brands of the same focal length.

**clickclick** · 07-12-2021, 07:27 PM

You probably need to unscrew that rear group. A lens removal kit like this will let you grip the metal ring holding it in and unscrew it:

amazon.com : Lens Repair Tool, 9pcs Camera DSLR Lens Repair Tool Ring 8-83mm Lenses Removal Rubber Accessory : Electronics?tag=pentaxforums-20&

**clickclick** · 07-12-2021, 07:28 PM - **1 Like**

And make sure you pay attention to the orientation of elements e.g. which direction the curves face. I make a sketch as I take lenses apart. It's easy to get mixed up even though it may seem obvious at the time.

**jon.partsch** · 07-12-2021, 08:57 PM

Originally posted by clickclick

You probably need to unscrew that rear group. A lens removal kit like this will let you grip the metal ring holding it in and unscrew it:

amazon.com : Lens Repair Tool, 9pcs Camera DSLR Lens Repair Tool Ring 8-83mm Lenses Removal Rubber Accessory : Electronics?tag=pentaxforums-20&

I have this set of lens ring cups and find it completely useless - it's silicone, and it's too slippery to get traction on a ring that I can't otherwise just remove with my fingers. I think you will find you need a "grippier" type of material.

**niceshot** · 07-13-2021, 01:43 AM

On the rear lens group you should be able to grip it with you fingers and simply spin it out keeping the whole rear lens group in tact .But in order to do this you need to remove the lens mount first.

**Sakura** · 07-13-2021, 06:58 AM

And most important, take a picture of every step you take, even the smallest steps.
You will probably need it very hard when assembling the lens again (been there, done that and needed it very much

)

**wildlybored** · 07-13-2021, 09:57 AM

Thank you one and all for the pointers. I already have had the mount removed so I will just try to clean as much as possible from the rear. I wanted to fool around with this lens to try some astrophotography with the O-GPS1 unit on my K70. If it stays stuck at F2.8 it is still much faster than my DA 18-135 or FA 100-300. Thanks again

**niceshot** · 07-13-2021, 02:16 PM

Originally posted by wildlybored

Thank you one and all for the pointers. I already have had the mount removed so I will just try to clean as much as possible from the rear. I wanted to fool around with this lens to try some astrophotography with the O-GPS1 unit on my K70. If it stays stuck at F2.8 it is still much faster than my DA 18-135 or FA 100-300. Thanks again

ZIPPO LIGHTER FLUID can be your best freind.

**clickclick** · 07-13-2021, 04:44 PM

Originally posted by jon.partsch

I have this set of lens ring cups and find it completely useless - it's silicone, and it's too slippery to get traction on a ring that I can't otherwise just remove with my fingers. I think you will find you need a "grippier" type of material.

I have a set of these, and have found them to work well. Perhaps a difference in the compound.

**pentaxus** · 07-13-2021, 10:13 PM - **1 Like**

Whatever japan Hobby Tool sells works for me also.

**arnold** · 07-13-2021, 10:21 PM

Isopropyl Alcohol really frees up sticky parts better than anything else I have used.

**niceshot** · 07-14-2021, 02:42 AM

Originally posted by arnold

Isopropyl Alcohol really frees up sticky parts better than anything else I have used.

MEK OR ACETONE,BUT mEK is better

07-13-2021, 06:58 AM	#9
Sakura Site Supporter Join Date: Jan 2010 Location: Netherlands Photos: Gallery Posts: 438	And most important, take a picture of every step you take, even the smallest steps. You will probably need it very hard when assembling the lens again (been there, done that and needed it very much ) Last edited by Sakura; 07-13-2021 at 07:20 AM.

07-13-2021, 09:57 AM	#10
wildlybored Loyal Site Supporter Join Date: May 2019 Location: Hendersonville NC Photos: Albums Posts: 82 Original Poster	Thanks for the input Thank you one and all for the pointers. I already have had the mount removed so I will just try to clean as much as possible from the rear. I wanted to fool around with this lens to try some astrophotography with the O-GPS1 unit on my K70. If it stays stuck at F2.8 it is still much faster than my DA 18-135 or FA 100-300. Thanks again

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07-12-2021, 01:53 PM	#2
niceshot Site Supporter Join Date: Mar 2014 Location: NY Photos: Gallery Posts: 1,563	Best bet is to remove the rear lens group and clean it from there. OR removing the grubs screws and twist off the front lens group. DO AT YOUR OWN PERIL. like I said go in from the back GOOD LUCK worked on this. lens a lot

07-12-2021, 02:02 PM	#3
jon.partsch Site Supporter Join Date: Oct 2009 Location: Northern California Posts: 442	Hello and welcome to the forums! I doubt you will find specific instructions for this lens, as I doubt it is a "classic" that many folks would be interested in using the time and effort to repair. Do you have experience with lens disassembly and service? Do you have the proper tools? I will say that it should be a simple lens design and with some practice reconditioning lenses, you should be able to make the repair fairly easily. I realize what I said above may note really help, but you can look on youtube for lens repair videos to see, in general, how old manual focus lenses are put together and what to expect when disassembling one. I will caution you that the "partial disassembly and flush with lighter fluid" approach for dealing with oily apertures has never worked for me - the oil always comes back shortly. The only relaiable approach in my experience is a complete tear-down, cleaning, re-lubrication, and re-assembly.

07-12-2021, 05:59 PM	#4
DWS1 Site Supporter Join Date: Aug 2018 Location: Arkansas, USA Posts: 1,169	Even though most of these old manual focus lenses are different they are mostly made from very similar designs. So you may be able to figure things out from repair videos from several different brands of the same focal length.

07-12-2021, 07:27 PM	#5
clickclick Loyal Site Supporter Join Date: May 2016 Location: East Coast Posts: 2,903	You probably need to unscrew that rear group. A lens removal kit like this will let you grip the metal ring holding it in and unscrew it: amazon.com : Lens Repair Tool, 9pcs Camera DSLR Lens Repair Tool Ring 8-83mm Lenses Removal Rubber Accessory : Electronics?tag=pentaxforums-20&

07-12-2021, 07:28 PM - 1 Like	#6
clickclick Loyal Site Supporter Join Date: May 2016 Location: East Coast Posts: 2,903	And make sure you pay attention to the orientation of elements e.g. which direction the curves face. I make a sketch as I take lenses apart. It's easy to get mixed up even though it may seem obvious at the time.

07-12-2021, 08:57 PM	#7
jon.partsch Site Supporter Join Date: Oct 2009 Location: Northern California Posts: 442	Originally posted by clickclick You probably need to unscrew that rear group. A lens removal kit like this will let you grip the metal ring holding it in and unscrew it: amazon.com : Lens Repair Tool, 9pcs Camera DSLR Lens Repair Tool Ring 8-83mm Lenses Removal Rubber Accessory : Electronics?tag=pentaxforums-20& I have this set of lens ring cups and find it completely useless - it's silicone, and it's too slippery to get traction on a ring that I can't otherwise just remove with my fingers. I think you will find you need a "grippier" type of material.

07-13-2021, 01:43 AM	#8
niceshot Site Supporter Join Date: Mar 2014 Location: NY Photos: Gallery Posts: 1,563	On the rear lens group you should be able to grip it with you fingers and simply spin it out keeping the whole rear lens group in tact .But in order to do this you need to remove the lens mount first.

07-13-2021, 02:16 PM	#11
niceshot Site Supporter Join Date: Mar 2014 Location: NY Photos: Gallery Posts: 1,563	Originally posted by wildlybored Thank you one and all for the pointers. I already have had the mount removed so I will just try to clean as much as possible from the rear. I wanted to fool around with this lens to try some astrophotography with the O-GPS1 unit on my K70. If it stays stuck at F2.8 it is still much faster than my DA 18-135 or FA 100-300. Thanks again ZIPPO LIGHTER FLUID can be your best freind.

07-13-2021, 04:44 PM	#12
clickclick Loyal Site Supporter Join Date: May 2016 Location: East Coast Posts: 2,903	Originally posted by jon.partsch I have this set of lens ring cups and find it completely useless - it's silicone, and it's too slippery to get traction on a ring that I can't otherwise just remove with my fingers. I think you will find you need a "grippier" type of material. I have a set of these, and have found them to work well. Perhaps a difference in the compound.

07-13-2021, 10:13 PM - 1 Like	#13
pentaxus Site Supporter Join Date: Jun 2010 Location: Central Coast, CA Posts: 1,312	Whatever japan Hobby Tool sells works for me also.

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07-13-2021, 10:21 PM	#14
arnold Site Supporter Join Date: Aug 2012 Location: Queensland Photos: Gallery \| Albums Posts: 4,293	Isopropyl Alcohol really frees up sticky parts better than anything else I have used.

07-14-2021, 02:42 AM	#15
niceshot Site Supporter Join Date: Mar 2014 Location: NY Photos: Gallery Posts: 1,563	Originally posted by arnold Isopropyl Alcohol really frees up sticky parts better than anything else I have used. MEK OR ACETONE,BUT mEK is better