Benjamin Franklin rebuild


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jmorris
January 11, 2014, 05:35 PM
The first gun given to me was a Benjamin .22 cal air rifle when I was 11 but it has been dead for years due to worn out parts. After ordering an RWS 34 to play with I came across a rebuild kit from Pyramyd air that cost about $28 including the special tool to take them apart (I was quoted $100 to rebuild it years ago).

Start by removing the stock screw and stock. Then remove the two roll pins that hold the muzzle cap inplace and bring the piston/rod back far enough to line up the pump handle pin with the lower muzzle cap hole and remove that pin. Now you can replace the piston head.

http://i121.photobucket.com/albums/o213/jmorrismetal/reloading/air/IMG_20140111_140148_195_zpsbcb63fb3.jpg

Next remove the trigger/safety (don't loose the detent ball for the safety) and rear retaining cap. The spring and hammer are under a little pressure but not too much, in any case remove these parts.

http://i121.photobucket.com/albums/o213/jmorrismetal/reloading/air/IMG_20140111_140413_347_zpse37f43b2.jpg

They send a tool that is square on one end that allows you to remove the retainer for the valve body.

http://i121.photobucket.com/albums/o213/jmorrismetal/reloading/air/IMG_20140111_141341_021_zpsefa43a2c.jpg

Opposite the square end of the tool, it is threaded to remove the valve guide. This took some "tapping" to get this out of mine.

http://i121.photobucket.com/albums/o213/jmorrismetal/reloading/air/IMG_20140111_141407_713_zpsc2568a57.jpg

The kit comes with all of the seals you need to replace and a new check valve spring but I did reuse the original lead washer instead of the PTFE split washer they provided.

http://i121.photobucket.com/albums/o213/jmorrismetal/reloading/air/IMG_20140111_142635_196_zps7932f7a6.jpg

Be VERY careful reassembling the valve body retainer. If you mess up the threads, both are brass and fine thread, you are going to be SOL. I put the tool in a vise and rotated the tube around while keeping everything in alignment. This too will take a little pressure (I also used air tool oil).

Then reassemble the rest like it came apart. I also cleaned everything once I had it all apart.

Before it wouldn't hold enough air to move a pellet and I have no idea what they are supposed to be but with a 14.3g pellet

3 pumps avg 407 fps
5 pumps avg 507 fps
10 pumps avg 647 fps

5 pumps and let it sit for half an hour went 505.6 with a second 5 pump shot right after going 505.0, so I guess old faithful is back in business.

http://i121.photobucket.com/albums/o213/jmorrismetal/reloading/air/IMG_20140111_155444_277_zpsebb4fa6f.jpg

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OcelotZ3
January 11, 2014, 07:14 PM
Nice, thanks for the photos.

Chevota
January 11, 2014, 07:31 PM
Excellent! I'm sure you're aware that those older Benj'z are sought after, and considering your history with it I'd never part with it. I don't care for pump guns, but a Benj or Sheridan are classic American history and I'd love to own one. So congrats on keeping the gun all this time, taking such good care of it, and a successful rebuild. My first at age 9 was a Crosman 760 which are about 8 steps lower on a 10 step latter compared to yours.
I'm sure you're well aware of the following: The ads I've seen say 685 at 8 pumps, but no mention of weight. Hard to guess if they meant the oem Benj pellets which I think are and have been 14.3, but who knows since mfg's usually use the lightest for advertizing. I'm no expert with these but I'd say 13.4ftlbs power (14.3 @ 650 you mentioned) is pretty good. Using 8 pumps would be maybe 600? The 50fps would cost you 2ftlbs, but still good. My 760 at 10 pumps was closer to 5-5.5ftlbs, or about yours at 3 pumps. If I had rec'd it instead of my 760 it would probably be thrashed by now like my 760 was after ~5 years, not that I'd still have it. So great story, great gun, and I'm jealous!
Are you looking for more power? Even if you're not you might consider it for reducing pumping, such as same power for 6-8 pumps.
How's your RWS 34? You like? Power and accuracy good? I've been waiting for a referb to pop up on http://airgunsdaily.com
Also wanted to mention fyi that Crosman sells parts and their prices are very low: http://crosman.com/cs/manuals They might not have your year listed, but maybe the newer parts are compatible, and possibly better. Best of luck with it!

jmorris
January 11, 2014, 07:39 PM
With the success of this one I might rebuild my Fathers that he had when he was a kid and was the first gun I ever shot. The wood is a little different and I think the safety is too but it has been a number of years since I looked at it.

Don't have the 34 yet and don't really need a pellet gun but always wanted an "adult" air rifle.

MartinS
January 14, 2014, 10:36 AM
Good work, thank you.

Deltaboy
April 6, 2014, 07:01 PM
Great job.

Bobson
April 6, 2014, 09:17 PM
Benjamin Sheridan. Great rifle, my last airgun was a B.S, and it was excellent.

JohnKSa
April 13, 2014, 09:42 PM
Be VERY careful reassembling the valve body retainer. If you mess up the threads, both are brass and fine thread, you are going to be SOL.This is a very important warning. It's very easy to screw this step up if you aren't careful.

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