The Crosman Recruit is a pellet rifle not a pellet gun. If you want to see how the rifle is assembled then see the link below for the diagram.
The Crosman model 150 was made between 1954-1967. It is a .22 cal pellet pistol.
The Phantom is a single shot, single break barrel Pellet rifle rated at 1000 FPS that cost around $90. It is a true pellet rifle. Deigned for target and hunting. The Daisy 901 is a combo BB/Pellet rifle that is a 10 pump for a maxim 750 FPS. and cost around $63. Designed for plinking and fun. Personally I have never been a fan of Combo rifles ( But that is my opinion )
The Crosman 1088 Pellet/BB is rated at 400-430 FPS
The breech area on any gun is the area where the pellet / bullet / BB is loaded into the barrel. The bullet stays here until the trigger is pulled.
You have to swing the forearm to pump up an air cylinder in the rifle. Usually it take about 8 pumps. When you pull the trigger it releases the air an propels the BB or Pellet.
Crosman offers a service to locate a repair center for their older guns and rifles. Click on the link below and then at the bottom of the page click on "Find a service center" it will direct you to someone who can rebuild your Crosman pellet gun.
It would help if you stated the model number. Crosman made several pellet rifles for Sears. You need to provide more information.
See the link below for the parts list and phone number for Crosman.
Daisy, Crosman, Remington and Beeman
100 USD
See the link below for the Owners Manual for the Crosman 1077 air rifle