Your rifle is a Marlin 81 made for Sears. Insure the rifle is COMPLETELY unloaded. Open the bolt, release safety,draw bolt to the rear, depress and hold trigger, slide bolt out of receiver.
To lock it into the breech
A lot! Breech loading simply means loaded from the rear of the barrel, instead of the muzzle. There are "trapdoor" rifles, top break, bolt action, lever action, autoloading, pumps, "twist" action, and a few others that did not really work out.
open the breech bolt and check the ejector, is a steel wire located betwin the breecch bolt and the action maybe is too wear
Try e-gunparts.com. Do a web search.
Find a good gunsmith.
Pull and hold the trigger, then pull the bolt back and it should release.
It's always best to clean from the breech end, but if you want to clean from the muzzle end, simply open the bolt, and then run your cleaning rod down the muzzle. Might be a good idea to put a piece of old rag in the bolt opening so the debis that is pushed out, wont end up in the action. Marlins are very easy to clean from the breech end. Simply open the lever half way, pull the lever screw, remove the lever, then pull the breechbolt out. You can now clean from the breech end.
There is a button at the beginning of the breach that you pusy in and the bolt will pull straight back out of the breach.
Should be on the barrel by the breech. It may be partially covered by the stock. In that case you will have to remove it.
bolt face signature
Press the release tab on the left side of the receiver and pull the bolt rearward
If you mean the bolt release, it's on the bottom left side of the receiver, away from the bolt handle. From the rear, insert a small screw driver, or other suitable device, and press down on the release while extracting the bolt. The bolt just slides in to reinstall (it presses the release for you).