When cleaning the Marlin 336W how far do I need to break it down and what is the best way to do it?

Answer 1

Open the bolt half way.

* Remove the lever pivot screw and pull out the lever. Pull the bolt out. The ejector is now lying loose in it's slot on the left side of the receiver. Take it out. Tweezers help if you've got big fingers.

* You'll probably want to take everything off the front end before you start on the action. Pull the magazine tube before you remove the forestock. The magazine spring could go boing on you if you don't hold the magazine tube plug(end cap)in when you take out the screw. The screw through the front barrel band holds the tube in. It goes though a notch in the tube, so take it right out before you pull the tube.

* Push up the lever safety, which is the little button behind the trigger, and lower the hammer. Remove the tang screw and pull off the buttstock. You'll see a curved piece that the hammer strut goes through and it tensions the hammer spring. Marlin calls it the hammer spring adjusting plate. Push it ahead at the top and slip it out of the notch in the bottom tang. Pull it and the hammer spring off.

* Remove the lower back screw on the right side of the receiver. The hammer pivots on it and I forget if you can wiggle the trigger out the top at this point. Remove the screw on the left side of the receiver and the screw on the bottom front of the receiver. They aren't the same length and I think the long one goes in the bottom. Be sure to check.

* Pull the trigger plate down by the tang, then back. It's the whole bottom of the gun. Mine's pretty tight, and takes a real tug. All the trigger parts and the spring are pinned to the trigger plate and shouldn't fly loose. Take out the hammer, if you haven't already. Take out the locking bolt, if it hasn't fallen out. Take out the larger screw on the right side of the receiver. It's the carrier screw. Take out the carrier. I didn't take the carrier rocker out of the side of the carrier. Done, unless I've missed something. Oh yeah, the little screw on the right side holds the loading spring (gate).

* Clean as needed, use a bore brush from the breach end, making sure not to change directions half way through. Run oily patches through until they come out clean. Clean out the insides of the receiver with a brush and q-tips, and clean any other parts that may have gotten dirty. Ensure that the bolt, firing pin, and any other important moving parts are oiled.

* Re-assemble in reverse order. I had to give the back of the tang a rap with a plastic hammer to get the trigger plate back in place. Don't force the screws back in, because the trigger plate isn't in right if they don't drop in the holes. Put the magazine follower in before you put the front barrel band screw in. The ejector has a small stud that goes through a hole in the left side of the receiver. This hole will be covered if you've got a side mounted peep sight. Hold the ejector in place with a finger tip when you slide the bolt in.

Answer 2

The only answer so far is way too much. For typical cleaning, remove the lever and the bolt, and clean the barrel from the breach end to muzzle. Be careful not to lose the ejector which will be loose in the left side of the action. Download a manual here:
http://www.marlinfirearms.com/pdfs/manuals/MFC_Centerfire.pdf