Nikkor 300mm f4 disassembly need help

[keyojimbo]

Searched a lot online with practically zero results. best I can find is a single image on facebook of the front and mid groups out of the body

I can see the three set screws under the lens hood around the front group, and 3 larger screws behind the front group looking down the barrel. removing the set screws under the hood doesn't appear to loosen anything. but can't figure out how to get the front group out of the barrel. the retainer ring lets me access the front element, then another retainer ring the 2nd element in the front group. the third element doesn't seem to have any retainer ring, probably on the other side but can't be accessed without removing the whole front group. I'm not seeing a way to getting the front group out to access the 3 screws that holds front section of the barrel to the lower lower half at the focusing ring. No notches or holes for spanners that I can see for the front group assembly.

any pointers greatly appreciated.

[Erik Lund]

Set screws sometimes needs complete removal, since they sometimes lock rotation, like for a big thread, also solvent can be dripped in when they are removed to release things.Good luck!

[Erik Lund]

Set screws sometimes needs complete removal, since they sometimes lock rotation, like for a big thread, also solvent can be dripped in when they are removed to release things.Good luck!

BTW check out Ricks page;

https://richardhaw.com/lens-repair-articles/

Here are similar lenses

[keyojimbo]

Thanks for reply. Yep I regularly visit Richard's blog as well as mikeno62 youtube channel.

Turns out the inner tube that sticks out above the retracted lens hood is the front group cell, and I managed to losen it with a soft rubber pad after removing the set screws under the lens hood. that was enough to  get me past the middle group and clean out some sizeable dust specks trapped between the rear and middle group. good enough!

Next one I'm still trying to figure out is Nikkor 300mm f4.5 AI-S ED IF. But I need to take some photos first.

[Erik Lund]

That’s great, hope you get it together nicely!

[Ezio]

Hi, I found this post because I have the same problem. I bought an old lens. It looks very worn :-)
He has sand inside and the focus ring is noisy. I have disassembled the front and back, but I cannot extract the lenses in the central body where the focusing system is.

I think I should remove the focus ring (where I removed the rubber) from the ring just behind. I removed the three small screws, but I can't unscrew the ring despite the presence of the two grooves. By the way: the two grooves are not at 180 ° ... strange.
I fear that the two grooves are not original, but made from a previous attempt at reopening

Can you help me? Thanks
Ezio

[Erik Lund]

I believe this is your next step:

Turns out the inner tube that sticks out above the retracted lens hood is the front group cell, and I managed to losen it with a soft rubber pad after removing the set screws under the lens hood. that was enough to  get me past the middle group

[Ezio]

Hi, I tried again, with your system I disassembled the front lens, but not the central lenses.
Does it just unscrew? Do I have to use a special rubber cone to disassemble the lenses?
Thanks for your help
Ezio

[Odesos]

Hi all ... I am currently in the process of buying the lens with some minor mold and decided that I will fix it myself, so I went down a rabbit hole to find how to aaaaaaaand somehow I found the solution as I found this post... registered to give you the link for the Service Manual PDFs and part lists etc

Service Manual:

https://www.nodevice.com/service-manuals/lens/nikon/af-s-nikkor-300mm-f-4d-if-ed/258339

Parts List:

https://www.nodevice.com/service-manuals/lens/nikon/af-s-nikkor-300mm-f-4d-if-ed/258336

Good luck everyone and I hope if your projects were stuck until now this will help you

[Ezio]

Hi, thanks for helping me. My lens is not AF-S, but the old only AF. The manual is different.
I can't find the repair manual of old AF lens.
Ezio

[ColinM]

Good luck in your mission Ezio

The 300mm AF-D was one of the first "serious" Nikon lenses i bought (from a local press photographer who found it in his store cupboard and took pity on me).
I had fun using it, then graduated to a new 300mm AF-S (later sold on to fellow NG member Nasos) then finally to the 300mm PF (which I still use).

Sorry, I can't help you with any fixes you're trying though

[Odesos]

Hi, thanks for helping me. My lens is not AF-S, but the old only AF. The manual is different.
I can't find the repair manual of old AF lens.
Ezio

I have the suspicion that the design is close to the 300 AF 2.8 and 80-200 ... as a general idea. But I will actually have the same lens soon, that I will be cleaning so I will let you know how it goes, maybe I will take pictures + video.

PS. Usually, there is a hidden bolt under the nameplate, you can heat it with a heat gun or hair drier to remove it ... just be sure to get yourself adhesive tape for later.

[Amar]

Searched a lot online with practically zero results. best I can find is a single image on facebook of the front and mid groups out of the body

I can see the three set screws under the lens hood around the front group, and 3 larger screws behind the front group looking down the barrel. removing the set screws under the hood doesn't appear to loosen anything. but can't figure out how to get the front group out of the barrel. the retainer ring lets me access the front element, then another retainer ring the 2nd element in the front group. the third element doesn't seem to have any retainer ring, probably on the other side but can't be accessed without removing the whole front group. I'm not seeing a way to getting the front group out to access the 3 screws that holds front section of the barrel to the lower lower half at the focusing ring. No notches or holes for spanners that I can see for the front group assembly.

any pointers greatly appreciated.

Today, I recieved a Nikon 300/f4 AF ED for funguss cleaning from my friend.

 The designing is similar to 80-200/2.8 ED, but still have some differences.

 For removing the front group of elements here are few steps;

 ●Totally remove all three tiny screw
 ● One or two drop thinner with the help of smallest screw driver in these three holes
 ● Also drop few on first retaining ring. Wait for few minutes.
 ● With the help of spanner, move the ring slowly so that whole group will move anticlockwise.
 
 ●
 

[Ezio]

Great, did you also remove the second group, the innermost one? That's where I have problems
Ezio

[Giovanni68]

Hello,

I am trying to disassemble my old 300D ED, I managed to take off the front lens but need to access the next one as there is slight trace of fungus there too, no way to unscrew the retaining ring and the three little screws on the barrel I can't figure how to get through, the lens been serviced by Nikon many years ago and they might have screwed the head of the screws, I have a set of screwers heads from iFixit but none of them seems to work.

Any suggestion on how to remove the screws and/or access the second lens in the front group?

Grazie