DIY repair of a leica m4 (rewind crank)

[joram]

Hello!
My leica m4 somehow took a hit on its rewind crank and now the part holding the flip out crank is slightly damaged, it blocks when turning the crank. It is a bit crooked, but no severe damaged. I think I can bend it back in shape by removing it. But here is my problem: I don't now how to remove it, I never did anything like that, though I already used tools for tiny screws and stuff like that. I found a pdf named something like "diy repair guide m2 m3 m4" but in fact it only talks about the m2, which has a different rewind crank.
I'd rather send it to youxin or someone, because it's such a small thing and german custom duty is a pain in the a** concerning repairs done outside the EU. And I doubt that this repair is worth some hundred euros.
So, I'd be glad if there is someone outside who knows how to unmount and remount the knob, maybe with a pictured guide. Thanks in advance
joram

 

[ferider]

Welcome to RFF.

It depends.

If it's just the crank, there is a lock screw, that you have to loosen, then you can take the crank off.

More often than not, the rewind axle does bend too and has to be replaced. For this you have to remove the top plate.

Don/DAG sells new cranks and axles.

I know because I replaced a bent axle/crank on my M6 (alu) with a modified Leicaflex one (brass). The M4 crank is the same but brass however.

Roland.

 

[joram]

further question

further question

Thanks for the fast reply.
When looking at my leica m4, i see two screws, one big right in the middle of the knob and a tiny one, on the side. I removed the tiny one after I couldn't turn the big one. But even without the smaller screw (a locking screw as i guess), i can not take off the knob or turn the bigger screw.
The crooked part doesn't look like being affected so much that it bent the axle.

 

[ferider]

Don't do anything to the big, top screw. Have a look here:

http://www.videojug.com/webvideo/how-to-remove-the-top-plate-on-the-leica-m6-camera

40 sec and afterwards.

Roland.

 

[Vickko]

Hello. That "big screw" you see is a slot cut into the shaft that holds the rewind crank knob. Get a suitable screwdriver and stick it into the big screw slot. Then grab the rewind knob and turn it counterclockwise. Don't be shy, since you've banged it, you may need to use a lot of force.

And there is a reason for that big slot - the shaft is two pieces. Holding the shaft with the slot allows you to unscrew the rewind knob, without separating the two pieces of the shaft. On the old M4, if you did separate the shaft before removing the knob, you had a bigger "pain in the butt" operation to then get the knob off.

Good luck.

Vick

 

[joram]

the video is great, just removed the crank in 10 secs. no i have to carefully bang it back in place 🙂
you made my night!
thanks!

 

[Roger Hicks]

Sod the screws.

Needlenose pliers. I had the same problem in 2003 or so in Slovenia. The crank spindle is bent. Straighten it in place with the pliers (I used a Leatherman). No problem since.

Cheers,

R.

 

[joram]

Today I finished the fixing, it really was only the knob which was crooked. I softened two forceps with issue and tape and bent the knob back in the right shape. Now it is mounted back in place and the m4 is back in action. No problem with any axle. Thanks for the help!
joram

 

[Vickko]

Good work. Feels good, doesn't it?

 

[schlops]

has anyone a link to a video? as the one posted is not working anymore!

 

[mooge]

Leica M4 rewind knob removal?

Leica M4 rewind knob removal?

Remove the M4 rewind knob - easy. Undo setscrew, block rewind fork and unscrew. right?

But mine was really tight, and when I gave it a twist, the rewind fork (inside the camera) came undone, not the rewind knob. So there's nothing to grip on. And yes I took out the setscrew.

Now what?!?!?!?!?!?!?!

side question: my rewind knob has no engravings on the outside and the little triangle on the inside. This is not original, right? M4 - 1 230 486

Thanks,
Eugene

 

[mooge]

Got it. With the cassette fork removed, jam a screwdriver into the hole and use that to prevent the rewind shaft from rotating.


ughhhhhh

 

[Black Rock City]

DIY repair of a leica m4 (rewind crank)

Use a paper towel or a lint free cloth to seize up the film spindle inside the camera body. Turn the rewind knob counterclockwise. If your rewind knob is bent out of true, I found the original Leica M4 part to be impossible to bend back into shape (Chrome finish featuring the letter R and the clockwise arrow). It gets work hardened and then cracks. Its made of brass or bronze even if it appears to be chrome.

The advice to bend it while still mounted on the axle is risky. Maybe a better strategy would be to find a screw with the exact same diameter and thread pitch and a matching nut. Then feed this through a piece of wood with the nut holding it in place (perhaps the nut is countersunk into the wood to lock it from moving). Then clamp this wood jig in a vise and attach your rewind knob to it. Now use padded needle nose pliers to work on it. But as I said above, odds are, you will break the rewind knob. Its not very malleable.

I feel like the best strategy would be to make a stainless steel C shaped insert and use JB weld to affix it inside of the knob to reinforce it into a circular shape. This is not for amateurs though.

Here is a working link to the video mentioned above.

https://youtu.be/KbtqDd-4qPI