Baikal MP-46M

Hi, I am new to this fine forum and this is my first post.

I have a Baikal MP-46M air pistol, by far my best airgun. It is about 10 years old and has not been fired very much. Recently, when I pump the handle and press it forward, I hear a slight sound of air leaking and although the bolt pops up, there is no power when closed, loaded, and the trigger is pulled. Since the pump handle can be returned with very little or no pressure, can I assume that it is the piston seal which has failed? When I put a little ATF on the seal, and pump it fast, it sometimes retains a little pressure and the gun fires.

I have read some of the posts on this forum about replacing seals on this gun, but I need to know more about it, like disassembly steps, and more detail about actual installation of the piston seal which some have mentioned here that that is very difficult to do. I have the correct seal kit which came with the gun.

I am a VERY senior person with not much skill in this area so I will need more direction than average!

Thank you for any help and direction that you can offer, I love this gun and want to be sure to do it correctly and with no more damage! 

by the way, what is "magic sauce" mentioned in some of the posts that I have read?

Regards, gkenny.