Chris's camera pages
Retina Ia or IIa focus mount strip down.
The focus ring on these cameras can sometimes be stiff from the grease having had all the volatile components dry out to leave a hard waxy base. Sometimes the focus ring becomes displaced if forced against the resistance of the old grease and comes adrift. Either way you will need to strip the focus mount down and relubricate it.
To start you will need to remove the shutter from the camera.
In the picture below of the back of a Retina Ia you can see one of the notches in the retaining ring that holds the shutter to the camera marked A. As you can see, the Retina IIa camera beside it has a much deeper rear lens group, and as a result, the retaining ring is well down in the gap between the rear lens group and the shutter mount.Unscrewing that thin retainer ring is by far easiest if you have a suitable tool designed to do the job.
The Beljan tool shown here, which is unfortunately no longer being manufactured, has a short tubular-section end with two small tabs projecting to engage the retaining ring, the two sides at right-angles to the tabs are machined away to make it easier to pass the tool through the film gate, and it is used with the front of the camera fully extended so you can actually get the tool into position.
Here is a photo of a shutter I have removed from a camera to show clearly how the tool engages with the notches in the retaining ring.
If you want to try something else, then you may find it easier to remove the rear lens group first to allow easier access to unscrew the retaining ring as shown in the picture below. A pair of needle-nose pliers with the tips ground to fit the notches will often work. Be especially careful not to slip and scratch the lens with the tool. The notch in the retaining ring is now plainly visible here in the picture below at B. Leave the four screws visible at the top and bottom of the retaining ring well alone they hold the guide posts for the helical mount.
Once you have unscrewed the retaining ring you can lift the shutter out of the focus mount at the front of the camera and in the picture below you can see the spacer attached to the inner focus mount with two screws at C and D. This spacer has a link at the top on the Retina IIa model which couples to the rangefinder. Remove the screws and lift out the spacer.(On the Retina IIa you will also need to remove the camera top to get at the single screw that forms the post that moves the rangefinder lever to remove this part.)
Especially if the focus ring is still firmly attached you should set the focus to the infinity position and scratch a line across the three rings visible in the picture below marked E. This will allow you to reassemble everything later on without having to readjust the focus. Next remove the four small screws that hold the focus ring to the helical focus mechanism. (Two of the screws can be seen here.)
Once this focus ring is lifted away you will see the plate that holds the helical focus mechanism in place. Remove only the six bright screws in the positions 1 to 6 in the picture below. In particular don't unscrew the four black screws, they hold the bellows to the front standard. Lift away the black plate.
Lift the helical focus mechanism straight out of the mount. The inner portion runs on the two guide posts fixed to the back of the front standard.
Here in the picture below you can see the old grease gumming up the works. Clean all of it away with a cotton bud or two soaked in lighter fluid or whatever other grease dissolving solvent you are using.
The helical focus mechanism can be cleaned separately . It is not hard to clean it adequately without completely unscrewing the inner part from the outer but if they do get separated, you can judge the correct relationship of one to the other by the relative position of the marks you scratched earlier. Note the two rings are nearly level at the front face at the correct position as shown in the picture further up the page where the scratch was shown marked E.
Lubricate the mechanism with fresh grease, don't go mad with it and wipe away the excess after reinstalling the black retaining plate (which will only fit one way around)and before refitting the focus ring, which you will be able to put in the correct position by lining up those marks. If your camera had a loose focus ring to start with then you will probably be able to judge the correct position by the marks left by the screws on the focus ring.
Finally reinstall the shutter mechanism, be careful with getting the gear meshed correctly, don't force the winder if it doesn't want to go!
And that is it. Contact me at email@example.com if you need more help.