Nikkor 24/2.8 Pre-AI: Fixing an Awful Squeal

[ic-racer]

I got this very nice Nikkor 24/2.8 Pre-Ai lens. Looks mint but...ouch it has a terrible squeal when focusing it.

Sounds like it is coming from the back of the lens. Lets see what could be the problem....

 

[ic-racer]

mikeno62 on YouTube has a video on how to take the lens apart, so I won't cover it all here.

Remove the rear screws. Mine had locking agent on them. Then remove the lens mount and the aperture ring.

 

[ic-racer]

Like many other Nikkor lenses, the rubber ring has to come off, then the front part of the focus ring has to be unscrewed. Sometimes there is a locking screw (not on this one) and some times it is very tight.

Once that ring is off, the locking screw for the 'nose' of the lens is visible and can be removed.

 

[ic-racer]

After taking the nose of the lens off, the lens block slides out.

 

[ic-racer]

The main helicoid is well lubricated and was not disassembled.

However, the secondary helicoid (for the floating elements) was dry as a bone. No helicoid grease at all. This is where the awful sound was originating. After some helicoid grease this secondary helicoid was smooth and quiet.

In the picture the helicoid has been turned out one complete turn. It comes off after 1/4 more revolution, at the brown arrow. To re-assemble, start it at the brown arrow and turn 1 + 1/4 turns to align the scribe mark with the green arrow.

Someone may have been in this lens before because it has scribe marks on it already.

 

[ic-racer]

All fixed and ready to be used on all my pre-ai cameras. Works great in stop-down mode on my other cameras with the flip-up AI tab.

Otherwise it would take AI Conversion ring #22, which is hard to find. Anyway, I already have a 24mm/2.8 AI for the other cameras, though, it is a different optical formula.