View Full Version : Benjamin Franklin rebuild

01-11-2014, 06:38 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.


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.


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


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.


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.


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.


01-11-2014, 07:28 PM
nice write up

01-13-2014, 07:23 AM
I have a great affection for those old air rifles. I remember other kids telling outrageous stories about the destructive power of ten pumps in one of these. When I lived in TN, I saw a kid hunting squirrels with a pump air rifle; its legal down there.


01-13-2014, 01:33 PM
Thanks for info,I can suggest the Williams peep sight for the Benji,made mine into a real tack driver!

01-19-2014, 11:03 PM
Times two on the Williams Peep! Just put one one my Benj .177 and .22 this past summer! Made all the difference in the world!

01-21-2014, 09:21 AM
How does the Williams sight mount?

01-21-2014, 12:01 PM
on the newer guns, there are holes pre drilled and tapped on the side of the receiver for it. you gun looks like a model 342? it may no have the pre drilled holes

04-05-2014, 04:52 PM
It is now kid approved.


04-23-2014, 04:06 PM
I would like to ask a couple of maybe dumb questions. Where did you get the scope mount? And will a Benjamin like yours but in .177 put down a Raccoon?

04-23-2014, 04:28 PM

I went thru the scope mount issue with my Benjamin 397 - made in 1994 - bought what I thought would fit. Benjamin B272 - did not fit my receiver diameter - only for current production models.

I read that the B270 would fit - but haven't seen any of those...

http://www.network54.com/Forum/275684/thread/1165720714/Can+anyone+describe+what+the+Sheridan++scope+inter mounts+look+like

See if that thread works for a little more info.

Geoff in oregon

04-23-2014, 05:03 PM
Jester a 22 benjamin is a better choice for something the size of a coon, but yet a 177 will do it. I've had model 342, 310, 347, and now a 317 and they've all taken coons, possums, barn cats etc. the 22 has a little better killing power. Your best bet with the 177 is a HEAVY pellet.

04-24-2014, 03:42 AM
My old Benjamin is probably a little older lol. I got it Brand New in 72 I think. Could have been 71 and I think it was $30.00 out the door at the time. I wanted the Sheridan Blue Streak but it was like $10.00 or so more and at 9 or 10 years old I just could not swing it lol. :)

Sorry I have never looked at the weight of pellets. When I go back to Wally World I will take a look to see what they have as far as weight.

But I am glad I found this thread as you might have noticed my Old Benjamin has a few years on it and I think it is in need of a rebuild as it will do something odd. If I pump it say 7 or 8 times and fire it there is still pressure in the rifle. Or to say it does not release all of the pressure with the shot?

04-25-2014, 09:45 AM
The original scope mounts I had for the rifle when I was a kid were machined from brass square bar stock and a perfect fit. The ones that are on the rifle now came from eBay