First Time. 1978 Caravelle 2879 Movement

[Firearmor]

Here we go. My first tear down and repair. 1978 Caravelle 2879 movement. I think I found a problem though. Picture 3 the screw won't come out and the gear moves back and forth. I found this little piece under it. I think someone cross-threaded the screw and messed up the threads. The screw is still in it so i don't know if that gear moving is normal or if i need to repair this somehow? Are there any Movements that are close to this one that there might be a tutorial on just in case i have problems with reassembly? 

 

[AndyHull]

The screw may be reverse threaded, but whatever the thread, just be very careful, otherwise you will torque the head off it.

I would suggest soaking it in penetrating oil. Also if you can see the other end of the thread under a microscope, you may be able to figure out which direction it is meant to turn.

I presume it is an ETA 2879 in which case this ranfft link shows  the related movements.

You might be able to find a service manual somewhere in the dark corners of the internet, but unfortunately I don't have one.
 

Edited December 8, 2019 by AndyHull

[Firearmor]

13 minutes ago, AndyHull said:

The screw may be reverse threaded, but whatever the thread, just be very careful, otherwise you will torque the head off it.

I would suggest soaking it in penetrating oil. Also if you can see the other end of the thread under a microscope, you may be able to figure out which direction it is meant to turn.

I presume it is an ETA 2879 in which case this ranfft link shows  the related movements.

You might be able to find a service manual somewhere in the dark corners of the internet, but unfortunately I don't have one.
 

The screw actually moves. It will turn left and right indefinitely. Thank you for that link. It will be very helpful. I have tried to search the internet for information on this movement. i started by typing in the 1133.50 that i on the movement which then led me to the Bulova 1133.10 and then led me to the 2879. It seems like an endless rabbit hole. Having a reference like the one you linked will help me out a Ton. THANK YOU AGAIN!!!

[dadistic]

The 2850 tech sheet covers the 2879.

 

ETA 2850,1,2,3,8 etc.pdf

[Colditz]

I agree with Andy Hull most likely a reverse thread. Looking at the pics the material looks like brass. Is the screw steel?

Cousins have a parts sheet for this calibre.

https://www.cousinsuk.com/document/category/eta-esa-movement-parts.

Scroll to : Page 4 of 7 - 3 up from the bottom. The screw you cannot get out looks like the crown wheel screw in the PDF, so very likely is reverse threaded. I cannot tell from the pic if the screw head has a line to indicate this. Try a gentle turn clock wise to release the crown wheel gear. I hope this helps.

 

[Firearmor]

1 hour ago, Colditz said:

I agree with Andy Hull most likely a reverse thread. Looking at the pics the material looks like brass. Is the screw steel?

Cousins have a parts sheet for this calibre.

https://www.cousinsuk.com/document/category/eta-esa-movement-parts.

Scroll to : Page 4 of 7 - 3 up from the bottom. The screw you cannot get out looks like the crown wheel screw in the PDF, so very likely is reverse threaded. I cannot tell from the pic if the screw head has a line to indicate this. Try a gentle turn clock wise to release the crown wheel gear. I hope this helps.

 

I can turn the screw both ways but it just keeps turning. I think the piece i found was the threads off of the screw. I think i will just leave it in rather than try to remove it. I will probably wind up messing it up and then i will have to find a replacement piece. Leaving it in shouldn't hurt anything. Thank you all for the help and the great material. It should make this cleaning and repair a lot easier.