Rebuild Parts & Techniques

Sheridan & Benjamin Kit Rebuild Tips
I don't sell valve tools. Bryan & Associates & others do. I do sell the Bolt Lug Tool so you can change the bolt o-ring.
Guns either don't pump at all, only retain one pump(blows pump back open) OR leak out the exhaust side. If it doesn't pump at all often it only needs a pump cup. When they are oil starved they fry relatively quickly for a part that could go 100,000 rounds or a MILLION PUMPS lubed with the Sauce.

I have made all the parts the factory has discontinued in the course of the Crosman takeover of the Benj/Sher Badges. So I can still make them last like they always did.
This company (Sheridan/Benjamin) made guns that lasted for 40 years. It was cheaper to buy the badges than to compete with them so Crosman bought the company and immediately cheapened the products quality and raised the price $30 so they could improve the margins.
I build Billet pump arms that are the best levers ever so we can use those on the old guns & current offerings. The Billet lever can be fitted to early guns but they don't NEED it like the current gun does. The Lever in the Rocker gun was the very first part Crosman discontinued and then the subsequent part was drastically cheapened to make it weak by design so it would fail when pushed.

The currently available factory parts are rubbish compared to most 70-80's vintage components still in the guns. If I were to do a NORMAL In House valve job($75) I would fit spares pulled from guns with low use that were in for my Steroid Upgrade. 90% of what I do is make guns High Performance(Steroid) and I take out perfectly good 80's spares so I can do Standard valve jobs on the other 10% of the guns I work on.  "if she works WAIT till she doesn't".  Sorry I don't sell take-outs, What you get in the kit is the best of the current stuff. Don';t leave those with more than one pump in them when in storage.
The key point is the Repair kit exhaust valve should not be used unless the Exhaust valve in the gun has failed or looks to be tired. Most Rockers go down because of an Inlet seal failure (weak link)and that is the only part you really need to change other than the other soft goods & pivots.

Test the power. If it does not leak and dumps all its air (with 8 pumps) the best thing to do is put fresh parts in the front of the gun. New Cup, new link pivot to piston, new keyed or round rivet, fresh front spring pin(make sure it holds good OR replace front plug($25). This will eliminate all the front end excess head space. Mop the goo out good (sock on a dowel) before you reinstall lever and piston group or you will push it(goo) into the valve group. This snot needs to be cleaned out not pushed through the gun.
The weak link in this system is the factory check valve. It wants to blow and will go first if the gun is pushed too hard or the lube gets put directly in the air hole. Then it instantly becomes a single pumper and will no longer build beyond one pump of pressure.
 6 digit Serial Numbers on the 200K plus all have keyed rivets if they are original. Before that is round rivet as a rule. Open the lever and look at the rivet that connects the lever arm to the lever link. If it is round on both sides(small on one side) then that is the round rivet. The kit has three factory parts(cup, front pin & Exhaust valve. The other six parts are Mac1. Two PTFE gaskets to take the front gasket and leads place. Link pin, rivet, inlet and bolt oring are all Mac1 Steroid Upgraded components. 9 Parts total. Get the Secret Sauce. ($4 for 2oz or $10 for 10 oz).
The kit I sell($25) comes with my Check valve and the Factory Exhaust. Unless the Exhaust seal is bad in yours it is more than likely a much better choice to reuse than to put the current stuff in. My Check valve(inlet) is the best ever. Hit it good to seat it with X visible. Use a solid drift just smaller in diameter than the check valve and strike it good so it is smashed into the seat. Make sure you are not trapping any debris when you do this. Cleaning the thing out is the key to a quality job. I soak it for weeks before I attempt to remove the crud. Some guns are completely impacted with debris as they were NEVER LUBED and consequently never cleaned themselves. They go down because of corrosive and/or congestive debris.
Get the secret sauce($4). It eliminates any future lever or pivot wear unless you abuse the gun by running it oil starved.
MOST important. All the Sheridans with the Spring steel rear sight set on wedges will eventually pop the solder joint loose between the Tube and Barrel. You must remove it immediately so the stress over time thing is stopped. I stretch it out and reinstall for the iron sight fans or you can glue it on and eliminate any possibility of solder joint failure while also being able to line the rear sight up with the direction of the front sight.
Williams peep was retooled last year(2012) to fix any issues with sighting in on the current guns. Unless you buy from someone with two year old stock you will get a revised one but the 80's and before  vintage gun would work with the earlier 5DSH Williams with no alteration. The current sight gives you more adjustment than ever and will work on both early and late guns. $40. Drill and tap for the Williams peep is $10 and is required on all models prior to 1986.
I'm always afraid of giving advice to DIY's on Dan repairs because I have seen so many actions screwed up in my time working on these. Make sure there are no nicks in the exhaust valve guide where the seal or gaskets sit. Try to make sure you get as much of the lead out of the valve nut threads as possible. It is too easy to cross thread the nut with the multi-tool. It is very important to turn it backwards till it picks up the first thread. If it doesn't feel right it propably isn't. Don't thrash the thing. I have a guided tap to fix jacked up threads. You must give me some material to work with so if you get the nut in there sideways please punt while I can still return you a functional piece.
Packing with the multi tool can be a challenge even for the best DIY so it is something not everyone will be able to accomplish. If you get over your head there are pros that can take the gun and still fix it.
Make sure you get all the old seals out of there. The front gasket can be a real challenge if it stays inside. Cleaning the snot out of the barrel, tube and valve is the key to a proper rebuild. I spend more time doing that than building the gun.
The oiling design element of all Dans and Benjamins seems lost on most people. The end of the piston where the link hooks up is either a porous metal part or one with a felt. That felt/part should always be saturated moist and delivering a film of lube to the pump tube ever stroke. You lube the pivots each with two drops at the rivet AND FRONT PIVOT BUT AT THE PISTON PIVOT GIVE IT 6-8 drops SO THE PISTON IS ALWAYS WET VISIBLY.
This insures enough lubricant is fed to the gun so the atmospheric contaminants & moisture can be carried through the gun and out with the discharged air. That is how the guns stays clean inside. Secret Sauce lubricant will eliminate wear and facilitate the internal cleaning when used on the Pump Pivots. You do not need to put it anywhere else as it is blowing through the system and will take care of everything if you keep the guide end of the piston wet.
Good Luck rebuilding your gun.