Benjamin Sheridan s397 repair

[Arthur]

I'm a newbie here and I'm looking for some info. I'm repairing my old Benji 397 and I found some info on the topic of repairing a 392,  which I've read is basically the same. You need a special tool to remove the exhaust valve body. I doubt I', going to find one so I'll have to make it. Can someone tell me the dimension of the back of the exhaust valve body, the internal dimension of square opening and the dimension of the center pin part. I should be able to find some square stock and drill out the center hopefully. thanks

[avator]

This thread should have all the info you need.

https://www.gatewaytoairguns.org/GTA/index.php?topic=123174.0

[Ronno6]

The tools required to do this job are basically 2:
Valve nut tool
Valve body tool

See ebay listing for the nut tool:     393243670664
That will do the nut, but not the  valve body.
FWIW the square projection measures 11/32" with corners chamfered, and a center hole large enough to clear the thread of the VB.
An important note: the nut tool had a shoulder at the base of the square.
That is helpful for the re-installation of the nut as it allows you to apply linear force to the nut.
That force is required to compress the valve spring..........otherwise the nut threads may not catch inside the valve.

As shown in the thread that Avator provided above, the valve body removal tool is best made from a length of 1/2" threaded rod and large wing nut.However, that tool required an internal thread of  9/32"-32 to match that of the VB......... Not a cheap acquisition.......
The tool on the right is a factory VB removal tool. It lacks the linear pull of the threaded rod/wing nut,step washer setup.
Using the threaded rod assures a straight extraction and usually makes the lead seals re-useable.

And, one important item is the centering step washer............used in VB removal and...most importantly....valve nut re-installation.
That keeps the tool centered and in line.......... makes things MUCH easier.....

[avator]

I wrap electrical tape around the shaft of mine to center them.

[Arthur]

thanks so much for all the info. I was able to take a piece of 5/16 square stock and drill it to make the first tool. 9/32-32 sounds like a very uncommon size but I might know a guy. should be able to get threaded rod fairly easy, should probably get same guy (machinist) to drill it for me. Thanks again, I'll update on progress.

[Ronno6]

eBay item #  116316291652

And others....just do a search

[Arthur]

update, tap came yesterday, tapped the threaded rod and got exhaust valve body pulled, got all springs and washers out. hopefully parts kit will be in mail today.  As I'm cleaning it up I'm looking in the back end at where the check valve seats, is there a preferred way of cleaning the valve seat, a little long piece of cloth with some rubbing alcohol ?

[Ronno6]

Get a long piece of 3/8" dowel rod.
Drill a 1/16" hole in the center of 1 end and push a small brad into the hole after removing the head
Punch or cut a 3/8" dia piece of 220 or 400 grit sand paper, preferably wet or dry paper and poke
it with the pointed end of the brad.Push against the end of the dowel rod.

Now insert the rod into the breech end of the rifle til the nail enters the intake orifice of the valve
Spin the dowel with the sand paper polishing the check valve sealing ring......

VOILA !!!

[Arthur]

sounds easy enough. Also when I was wiping it out with a rag on a gun cleaning rod, out came a flattened o-ring. I'm thinking that should go on the lip of the exhaust valve body, would that be it.  Thanks again for all the help

[Ronno6]

Hmmmmm.
Sheridan 347 rifles used a synthetic seal in front of the valve, and a lead seal between valve body and nut.......
Benjamin used lead in  both locations.

btw.........IIRC the 397 had a removable cartridge valve, as do the Crosman pumpers.

347 used the soldered in valve, as ours appears to be.
What am I missing??

[Arthur]

I have the original box, the flap on the end reads-Benjamin Sheridan single shot .177 cal 4.5mm pneumatic pump pellet air rifle model S397. The left side of the barrel is stamped--model 397p 4.5 mm (.177cal) pellets only, there is what I take to be a serial number v117442w. The right side of the barrel is stamped with the Ben-Sher -Racine W zip code usa info. On the underside of the barrel where the intake valve body  is there is a small round indentation that looks like a drilled hole that was filled and polished. Don't know what else to tell you. The Ben-Sher website production reference chart shows the s397 being produced from '91-'93. There is a lead washer between the exhaust valve body and the valve body nut. I think that's everything I know. Thanks

[Ronno6]

I can't argue with that!
It is odd, tho, that the Benjimin and Sheridan 397 rifle parts diagram all show the cartridge valve.

On the older Benjamin 347 diagrams a lead seal washer is shown on both ends of the exhaust valve body.
Whereas the Sheridan "Streak" guns had a synthetic seal in front of the valve body, and a lead seal between the rear of the body and the nut.

I verified that with Mike Baker.........

[Arthur]

Ok, my kit came from Henry Ford Airguns, the exhaust valve assembly shaft is real tight going into the exhaust valve body. It's got a steel shaft where as the old one has a brass shaft. Do you think I should rub the shaft down with some emery cloth to get it to fit easier. Another question is which way does the check valve go in, flat side first or "dimple"side. The third pic in that"Gateway to Airguns" thing earlier in this conversation shows valve body-exhaust valve assem.-spring-washer-small spring check valve. Looks like check valve is flat side to seat. Just trying to do this right, don't want to have to redo because of simple mistake. Thanks

[Ronno6]

I cannot speak to the stem shaft situation.
I would ask Mr. Henry.
The check valve disc goes in with the rubber side to the front.
You wanna see the brass side when you look into the valve.

Did you receive new valve springs, especially the long, tapered one?

[Arthur]

No springs in the kit I got, what length are supposed to be, the big one seems pretty stout, why is there that shorter fine spring

[Ronno6]

No springs in the kit I got, what length are supposed to be, the big one seems pretty stout, why is there that shorter fine spring

Problem MAY be...........if your original stem has the small nub on the end, but your replacement stem has the LARGE nub
it will not nest into the small end of the spring........

You will need the spring that is larger diameter at the small end...........

[Arthur]

Ok, new dilemma, I seem to have lost the valve nut. Got everything ready to go and no nut. Any idea if there are replacements for sale anywhere

[Ronno6]

Ok, new dilemma, I seem to have lost the valve nut. Got everything ready to go and no nut. Any idea if there are replacements for sale anywhere

Contact member Mike Baker

[Arthur]

I am trying to send a message to Mike Baker, I put in his name and got a screen that said he goes by Plinker, but when I try to send it gives me a error message. Do you have better contact info or am I just doing something wrong

[Ronno6]

I will PM you his phone #

PM sent.

Silly suggestion, maybe, but check the end of your square ended nut removal tool......
the nut may still be there from when you extracted it........