Nikon F4: Quick fix for gummed mechanics parts?

Andreas Thaler · Nov 29, 2023

One problem with the Nikon F4 is resin buildup in the mechanics of the mirror box, which prevents the small aperture values from forming. In addition, a scratching noise can be heard when you press the stop down button.

The camera has to be heavily dismantled for cleaning and lubrication, which, as always, involves the risk of additional damage being caused. I also assume that the massively built camera has screws that are difficult or impossible to loosen.

The location concerned should be accessible via an opening around the apperture lever in the mirror box.

I'm thinking about trying the method described by Thomas Tomosy with fine graphite powder stirred into Zippo lighter fluid. The mixture could be introduced with the needle of a syringe, with neighboring parts of the mechanism also being lubricated. Zippo should do the cleaning part.

Graphite powder is suitable for lubricating fast-moving mechanical parts and should not cause any damage. However, there is a circuit board with electronic components underneath. Since graphite is conductive, there could arise problems here, but I don't know whether the amount added is enough.

Is there any experience with this or the use of graphite powder?

Andreas Thaler · Nov 29, 2023

Probably no one, then I'll give the method a try.

The camera is already broken, so I'm pretty relaxed about that

But first I will check how electrically conductive the mixture of Zippo lighter fluid and graphite actually is without burning my fingers.

Report follows

Dan Daniel · Nov 29, 2023

What about molybdenum disulphate? Not sure about its conductivity but it has basically replaced graphite for most dry powder lubrication as I understand it.

Andreas Thaler · Nov 29, 2023

Dan Daniel said:
What about molybdenum disulphate? Not sure about its conductivity but it has basically replaced graphite for most dry powder lubrication as I understand it.

Thanks, Dan!

As I understand it, Moly is one of the lubricants for heavily used mechanics that do not run quickly. For example, the axis of the elevator lever. The mechanics in the mirror box run quickly, so it needs something light like graphite.

Or have I misunderstood the technical term? That's not a paste?

reddesert · Nov 29, 2023

I don't have a Nikon F4, but I'm curious about your diagnosis of the problem. The aperture on a Nikon lens will stop down by itself when off the camera. The role of the lever on the camera body is to hold the aperture open, and move out of the way when the shutter is fired. (With the additional feature that on later cameras and lenses, in program mode the body lever limits travel to set the aperture, but that is not germane here.) So I'm not sure if you mean that the body lever is moving too slowly for the lens to stop down fully during the exposure, or that it actually doesn't reach the full limit of its travel and physically prevents the lens to stop down. That plus the scratching sound when stopping down makes me wonder if the lever is bent.

The lever can be bent if a user tangles the body and lens levers when forgetting that Nikon lenses mount opposite from normal direction (righty-loosey rather than lefty-loosey). I did this myself to my first Nikon around 35 years ago, and had it fixed by a shop.

Andreas Thaler · Nov 29, 2023

Thanks!

The problem now occurred with my second F4, which had previously worked perfectly and had been lying unused in the cupboard for a long time. So I'm assuming it's resinification.

There is also a repair report that describes dismantling the camera and cleaning a gear. I'll provide the link.

The thing is that the lever in the mirror box no longer moves the entire distance.

Andreas Thaler · Nov 29, 2023

Uh! It's a report on Photrio by @F4user

I had completely forgotten that

Nikon F4 aperture lever repair

F4user submitted a new resource: (there was a url link here which no longer exists) - Nikon F4 aperture lever repair WARNING : Those instructions are for skilled persons with some knowledge of mechanics and electronics. Don't follow if you are unsure about your skills. F4 Aperture lever...

www.photrio.com

The culprits for defective work are: aperture lever spring and hardened shaft grease of toothed gears.

Ibid.

Andreas Thaler · Nov 29, 2023

Dan Daniel said:
What about molybdenum disulphate? Not sure about its conductivity but it has basically replaced graphite for most dry powder lubrication as I understand it.

Sorry, I mixed that up.

Yes, that sounds interesting, I even have it in my chemistry box.

Molybdenum disulfide - Wikipedia

en.m.wikipedia.org

vandergus · Nov 29, 2023

Yeah, Molybdenum disulfide (colloquially known as dry moly) is usually purchased as a powder. It's often used as an additive in grease used on high wear surfaces, which is what you were probably thinking of. That grease is commonly used in camera repair to lubricate latching surfaces and other points with high friction. But, yeah, it's not used in high speed areas. The powder, on its own, is sometimes used as a dry lubricant and rubbed into the surface, which is more applicable for high speed parts.

For the Nikon F4 repair, I certainly wouldn't recommend injecting any kind of concoctions. Yeah it's a complicated camera, but they can still be disassembled. As usual, take it apart, clean it, lubricate it is the best practice. But if it's already a goner....feel free to play around, I guess.

Andreas Thaler · Nov 29, 2023

vandergus said:
For the Nikon F4 repair, I certainly wouldn't recommend injecting any kind of concoctions. Yeah it's a complicated camera, but they can still be disassembled. As usual, take it apart, clean it, lubricate it is the best practice. But if it's already a goner....feel free to play around, I guess.

I have great respect for the design of the F4; in terms of massiveness, it is in a different class than, for example, a Minolta X-700. Looking at @F4user tutorial, disassembling and assembling is an obstacle course

I'll look through the tutorial and my documents to see how it's set up in the mirror box and where the electronics are. If the syringe doesn't work, I still have to try dismantling the F4. There shouldn't be any short circuits of course.

Dan Daniel · Nov 29, 2023

vandergus said:
But if it's already a goner....feel free to play around, I guess.

I will, unfortunately, never forget being in a local camera store that sold used cameras. Someone came in, having traveled 100 miles or so, because of a problem with a camera he had bought a week earlier. The owner played with it a bit, then pulled the bottom off of the camera. And proceeded to squirt lighter fluid into the camera. And I mean squirt! The camera started working, the excess fluid was allowed to drip out, the bottom installed, and the customer left happy with his working camera.

I assume that in an enclosed camera body, the lighter fluid would last 12-36 hours, and then everything would grind to a halt again...

Andreas Thaler · Nov 29, 2023

Should I flood the F4 with WD-40? I have a can here!

Andreas Thaler · Nov 29, 2023

Dan Daniel said:
I assume that in an enclosed camera body, the lighter fluid would last 12-36 hours, and then everything would grind to a halt again...

To be honest, I had already tried electronics cleaner, it doesn't damage anything but it degreases. The F4 worked with it - and the next day it was even worse. This was at a time when I wasn't particularly familiar with camera repairs

Andreas Thaler · Nov 30, 2023

On the other hand, I don't know whether generous lubrication of the entire mechanism on the mirror box with graphite is good. Some things will run dry there, I just don't know enough about that. Let's see what my research will reveal.

4season · Nov 30, 2023

What a wonderful how-to guide from @F4user! Although it's not a trivial amount of disassembly, the camera really looks as if Nikon designed it to be serviced. And my previous experience servicing F and F3 has really helped me to appreciate what the insides of a high-end camera should look like.

Graphite + naptha: My powdered graphite is fairly coarse, and it almost immediately falls out of suspension. But this lead me to try other dilute solutions, such as naptha + Molykote G-N with good results (I have not yet tried pure MoS2).

Andreas Thaler · Nov 30, 2023

Before @F4user wrote his tutorial, he summarized the problem as follows:

This problem rise from wear, loose strength of the spring who drive the aperture lever combined with lubrication problems of some gears.

Post in thread 'Nikon F4 doesn't seem to stop lens down completely'
https://www.photrio.com/forum/threa...stop-lens-down-completely.104631/post-1381658

This means that with a Zippo/graphite injection I can at best solve the third sub-problem.

Andreas Thaler · Nov 30, 2023

On the other hand, disassembling and assembling an F4 is not a simple matter as can be seen. The rule is to repair with the least amount of effort. And once I get to the affected area, I can't do anything other than clean and oil, because I don't have a spare spring and I can't adjust the mechanics there due to lack of knowledge.

@F4user announced that he would include this in his tutorial, but apparently that didn't happen anymore.

I have now decided and will try the syringe. The botched spraying of electronics cleaner at least made the mechanics work for a day, so maybe it's actually just resin buildup.

Andreas Thaler · Nov 30, 2023

Andreas Thaler said:
Uh! It's a report on Photrio by @F4user

I had completely forgotten that

Nikon F4 aperture lever repair

F4user submitted a new resource: (there was a url link here which no longer exists) - Nikon F4 aperture lever repair WARNING : Those instructions are for skilled persons with some knowledge of mechanics and electronics. Don't follow if you are unsure about your skills. F4 Aperture lever...

www.photrio.com

Ibid.

Episode 1 of the tutorial:

Nikon F4 aperture lever repair

WARNING : Those instructions are for skilled persons with some knowledge of mechanics and electronics. Don't follow if you are unsure about your skills. F4 Aperture lever problem driving the lens down. This will be a long thread with ~100...

www.photrio.com

Andreas Thaler · Nov 30, 2023

The camera was in the bag for over a year after being treated with electronic spray and has not been used since:

I attached a Nikkor AF 50/1.4 D and set the smallest aperture to f = 16 in mode B. The aperture blades closed slowly and jerkily to the smallest opening:

That's not a bad thing for now

I introduced the Zippo lighter fluid and graphite powder concoction several times with the pipette and worked the mechanism with the stop down button. I held the camera in all directions so that the emulsion could spread. Then used the bellows to blow into the opening around the aperture lever:

The scratching noise when pressing the shutter button has diminished somewhat, but the aperture now closes properly. It also works with an AF 28-70 D, here at the smallest aperture of F = 22.

The electronics show no errors due to the treatment:

Today I will keep the camera under observation and movement:

I'm excited to see what will happen

Andreas Thaler · Nov 30, 2023

The aperture continues to work perfectly. This looks good at one point, but tomorrow will show whether it stays that way.

Andreas Thaler · Dec 1, 2023

The treatment made a difference:

The smallest aperture closes correctly. However, the aperture doesn't close as quickly as it should. And the mirror doesn't rest completely on its shock absorber when the camera is tilted backwards and triggered.
In the mirror box you can see that the aperture lever does not move all the way down the full distance. If I help in position B, there is a slight scratching noise and the mirror goes all the way up.
The camera functions are ok.
The problem was therefore partially solved by treating with Zippo lighter fluid and graphite.
No identifiable damage was caused as a result.
Perhaps further treatment with an attempt to better reach the suspected problem area with the pipette would help. To do this, I could use heat to shape a plastic pipette to suit.
In any case, you can work with the camera.
I still cannot identify any material fatigue/wear that @F4user suspected, as in this case the treatment described would not have improved anything.
This is a quick fix and not a professional cleaning and relubrication, but is justified by the effort and risk of dismantling/reassembling this complex camera.
I also assume that after removing the mirror box and partially dismantling the mechanics, adjustments will be necessary, which @F4user unfortunately didn't go into in his tutorial. Nikon points out in its service manual that setting the exposure metering/autofocus requires Nikon's own software, which is not available.

+++

All information provided without guarantee and use at your own risk.

4season · Dec 1, 2023

I've found a high speed video app on my phone very useful for observing behavior of fast-moving camera parts, like focal plane shutters. The old Nikon 1 mirrorless cameras had a low-res but fast burst rate which might be even better for the purpose, if you can get one of those cameras cheaply.

Andreas Thaler · Dec 1, 2023

4season said:
I've found a high speed video app on my phone very useful for observing behavior of fast-moving camera parts, like focal plane shutters. The old Nikon 1 mirrorless cameras had a low-res but fast burst rate which might be even better for the purpose, if you can get one of those cameras cheaply.

Thanks for the tip!

My old iPhone is very useful, at least I can see more in slow motion than without it.

BMbikerider · Dec 1, 2023

Andreas Thaler said:
One problem with the Nikon F4 is resin buildup in the mechanics of the mirror box, which prevents the small aperture values from forming. In addition, a scratching noise can be heard when you press the stop down button.

The camera has to be heavily dismantled for cleaning and lubrication, which, as always, involves the risk of additional damage being caused. I also assume that the massively built camera has screws that are difficult or impossible to loosen.

The location concerned should be accessible via an opening around the apperture lever in the mirror box.

I'm thinking about trying the method described by Thomas Tomosy with fine graphite powder stirred into Zippo lighter fluid. The mixture could be introduced with the needle of a syringe, with neighboring parts of the mechanism also being lubricated. Zippo should do the cleaning part.

Graphite powder is suitable for lubricating fast-moving mechanical parts and should not cause any damage. However, there is a circuit board with electronic components underneath. Since graphite is conductive, there could arise problems here, but I don't know whether the amount added is enough.

Is there any experience with this or the use of graphite powder?

In short, you seem to have little experience in servicing what is a delicate and intricate masterpiece if electronics and engineering. What is your camera worth. Make a mistake, loose a screw, use the incorrect lubricant, or even worse don't have sight of a repair manual or special tools then you will almost certainly end up with it being worse than what it is now.

Take it to a competent repairer and if they make a mess of it you have a legal channel to recoup at least the value of the camera. Do it yourself and make a mess of what you are doing then you have lost out big style and no comeback.

Why take a gamble?

Andreas Thaler · Dec 1, 2023

First of all, we're on a camera repair forum. It can be assumed that it is about DIY.

Secondly, why shouldn't I try to find a solution to the problem myself?

I respect complicated devices, but I'm not afraid of them. Before I pick up the screwdriver I inform myself as best I can or ask others. I've had enough experiences with workshops; these experiences cost me a lot of money.

And my most beautiful Nikon F3/T would still have a broken LCD and my Canon T90 would still have a broken display. These repairs weren't too easy either, but it worked. But I only tried that because I had previous experience with repairs.

Or do you think a workshop would have accepted these repairs? And if so, at what price?

You should have more confidence in yourself, without being a fool. That's how you get further. This is also why I write my repair reports here.

Nikon F4: Quick fix for gummed mechanics parts?

Privacy & Transparency

Privacy & Transparency