PBB gave step by step directions on here a while back. It is quite easy using basic hand tools. I did a quick search and didn't find it but maybe you could. I have done it but don't feel comfortable giving directions.
Ok.. I looked for that E-mail and lost it.. So.. I'll try again..
First.. remove stock,barrel,forend,and trigger
Second.. make a drawing or take a picture of the locking bolt latch.. the triangular shaped piece of metal on the right hand side..with the release pin and spring and plunger on top.. THAT is important to study how they fit together..
Third Use a punch to press the cross pin that holds the locking bolt catch.. and the firing pins out.. from right to left.. Be careful the triangular locking piece doesn't fly away.. as the tiny spring and plunger on top want too fly also..
Fourth.. remove both firing pins and springs.. YOU MUST REMOVE THE SPRINGS..
FIFTH.. note the position on the top lever return spring housing.. IT IS NOT A SCREW THAT TURNS OUT.. THE MARK IS FOR INDEXING..
Sixth.. use a small punch and 2 oz. hammer to gently nudge the top lever out.. There is a small hole in the locking bolt you will push thru .. It's very light.. gentle taps.. NOW.. when you reach a certain point..the top lever return spring housing will come flying out the back..with the spring.. Wear safety glasses..I catch it in my hand..or a rag held in front of it will do..
Seventh.. remove top lever completely.. remove locking bolt.. clean everything..
Eighth..reinstall the top lever locking bolt disconnector.. That funny shaped rod that has the cut out for the triangular piece of metal.. then put the locking bolt back in..(a small spot of grease in the slot where the top lever cams..can't hurt..
Nineth..start the top lever about 5/8's the way in the hole..and insert new spring in top lever return spring housing.. The teeth,grooves.. whatever you want to call them.. face the top lever.. Now.. if you have a vise..it helps.. Push on the top lever return spring housing..beyond flush while pushing the top lever fully home.. Remember.. the tit on the end must fit into the locking bolt..or it will not go all the way in..
Tenth.. If you made it this far.. the rest is easy.. insert the plunger spring and plunger..that goes on the top of the locking bolt lock.. Get the release pin indexed so the triangular piece will slide in back of it.. while the tiny spring and plunger push on the top.. When the hole lines up.. start the cross pin back in the hole... Then install the right firing pin and spring.. and push the pin a little more... the put the left firing pin and spring in..and finish pushing the lock pin in.. so it's flush on the left side.. and has plenty exposed to hold the triangular locking piece in place..
Eleventh.. check for function before putting it all back together.. If everything works smoothly..put a few drops of breakfree.. tri-flow.. slip 2000.. whatever you like down the locking bolt.. get some by the top lever.. wipe down so no oil gets in your stock.. Reassemble your shotgun.. knowing you did a good thing for it..
If you lost the little plunger that goes on the spring.. you'll need to get another before you put the gun back together.. Where ever you get the spring.. also get a spare plunger.. Also.. many aftermarket springs are to long.. I'll save fitting the spring for another scession.. But basically.. the top lever should stop on the receiver.. IF it does not.. grind 1/8 turn at a time.. and retry.. until its correct.. to much.. and the spring is weak.. not enough..and you're stopping on the slotted portion of the top lever..(not good)..
Hope this helps.. Everyone needing this.. please make a copy.. E-mail me if you need help.. All Good.. Mike
If God wanted me to do this kind of a project, She wouldn't have invented gunsmiths. I'd rather throw a few honest bucks at somebody who knows what they hell they're doing than spend a weekend looking for tiny little springs on my hands and knees on my garage floor. It sounds like 15 minutes real work and 12 hours of frustration, followed by an embarrassed trip to the gunsmith I should have used in the first place.
Mike (PBB) good set of instructions to follow (cute tool for compressing the spring by the way!) - I found your comment at the end about the correct spring length helpful. I've changed quite a few top lever springs, but haven't paid attention to that issue & didn't realise the top lever should actually stop against the surrounding housing of the receiver. I will be careful to check that in the future and if there is no contact, carefully grind the spring shorter until there is contact. Cheers from Australia, Mike
The factory springs I've only had a few to long..and I've changed plenty of them.. those from Marcello were equally good.. It seems one to long slips in now and then from everyone.. I'm having the holy grail of top springs made right now.. but uncut.. so I'll need to hand fit each and every one.. i'm looking for a 5 year life or 50,000 shots.. Time will tell..
When you pay a good gunsmith to change a spring.. it's not about the spring.. It's looking after everything else.. and giving a good cleaning.. preventing the problem before its a big problem.. You might have noticed a big box of percision stones next to me at the GRAND.. That box cost as much as a Perazzi with stones.. fine files.. diamond hones..lapping compounds etc.. Those $40.00 to $80.00 small parts add up quickly.. They correct the wear patterns as well as other problems.. You got all that last year for $47.50.. Hopefully Dan will go up on his prices a little bit..
hope to see you all at the GRAND.. All Good.. Mike
At the Grand.. the VERY first spare parts that go on my bench is the tiny spring and plunger.. While I change them all day long..a few want a look around the room.. and I don't have time to retrive them.. It happens to the best of us.. Out of many hundreds of gun.. I lost 2 plungers last year.. and 1 spring.. It's like paper in a office.. if you handle paper.. one day you'll get a paper cut.. On a up note.. I'm considering making a run of top lever lock plungers..so I'll have a can of them.. It's THE most common lost part in a cat4 receiver.. Anyone with a cat3 (top lever trip pin at 12 o'clock) should get the top lever lock pin and plunger with spring assembly.. All Good.. Mike
If you need a top lever return spring plunger.. a small piece of 7/64 drill rod chucked in a drill with a hand file can easily make one.. Don't harden it.. just trim to length after you turn a small section down to fit inside the spring.. The 7/64 rod is already the right size OD.. and the rest isn't critical.. I don't have a factory one in my hands now.. or I'd give you the OAL. It's about 3/8" total length.. i'll get back and update shortly..
OK.. the tiny plunger is .470 total length.. body diameter seems to run from .092 to .105.. and everything in the middle.. so check the rod diameter before you cut it.. It needs to clear the hole that the spring goes in.. .170 of the .450 needs to be turned down to .065/.070 ... That is the portion that fits inside the spring..which seems to run from .090 to .106.. While all of this seems like alot.. it's really not that exaction.. You can chuck a piece of 7/64 rod in a drill.. and cut a little down on the end for the spring with a fine file.. Take a pair of sidecutters and cut of 1/2".. and file or grind the end flat so its a little shy of 1/2".. DONE.. If you don't have a piece of 7/64 drill rod.. but do have a micrometer.. use a nail..and turn it to size.. Really.. it's not rocket science.. I have a pile of them people made over the years..and guess what..??????? They all worked fine..just I replace them with factory parts.. All Good.. Mike