Hello there,
can someone provide me a link or copy of the Graflex 3A service/repair Manual

also, can you tell me about the manufacture date, the serial is : 85272

my camera looks strange to me, from the plates, it is a mix with old version and last version, the top plate for the mirror looks new and the bottom for the speed looks older

I hope you understand what I means, English is not my language, sorry

Well, you actually have the Autographic Pen!
Dates were not recorded for cameras that early. Its 77 from the end of an order for 500 cameras and was probably listed in 1915 but no latter than 1916.
The side plates for the curtain are period correct.
I made up service instructions for the 3A based on one I returned to service. It too was an Autographic model.
The service instructions can be downloaded from my google drive:
https://drive.google.com/file/d/0B1sPJkp-MdghSm5xZW9nMVlfOFE/view?usp=sharing
along with Graflex SLR service instructions:
https://drive.google.com/file/d/0B1sPJkp-MdghRkRId1EwT0dpNkk/view?usp=sharing

Thank you Charles for sharing your knowledge
I have to make more tension to the curtain, and I saw this video on Youtube :
https://www.youtube.com/watch?v=kZuo_j1DfKs

As I never opened a Graflex camera, I was wondering if this tutorial can be applied to the 3A ?

And for my taste, the curtain is very "dry" (not sure is the good word) is there something I can do to make it more flexible ?
I already applied shoe cream to the bellows and the hood and they are much better now

the mirror is also very "stung" but can be use like that.

The curtain needs a full CLA. Tightening the tension will not compensate for dried out grease causing the rollers not to turn freely.

I do not know what products you have available where you are. Pledge Furniture Polish in the yellow can works as does Tire Wet which makes the rubber on your car's tires look wet.
The curtain is rubberized silk.
See https://graflex.org/helpboard/viewtopic.php?t=5624 for tips on recoating a curtain.
The 3A is a Reflex Camera.
Very little of that video is directly applicable to the 3A, the wind plate and tension plate removal and installation will be very similar.