Repair my B21

so is it worth repairing, if in good shape YES but on the other hand they don't have great value

so if you had a friend that had the skills and you got the parts, that would be best but to ship it 2 ways and have the labor added and the parts you would reach a point that the cost is maybe more then it is worth in 100% condition

so that is to be considered

I have a BEC Eurolux  model 21 Thunder in .177 and it seems to be a fine rifle but I also think that all 21's are not the same in quality

so not much help really, just some opinions

so do have someone fix it for X amount of dollars or do you take those dollars and buy a new gun and sell the 21 in non working condition

oh it's a Diana model 48 clone

so good luck and take care

mike

Some time back Rich in Mich quoted me a very good price for repairing it but then I think he stopped taking new work before I got it to him. 

A search referenced some detailed instructions on the Maccari site but I can't find them.  Maybe I'm stuck working on it myself. 

If you wouldn't mind, I could use recommendations for:

Disassembly instructions

Replacement parts.  Will the tune kits on Pyramidair for RWS 48 fit? 

You might try getting in touch with John in PA (John Thomas) and see if he can help you. Last I had heard his tune prices were very reasonable. His contact info is in this link.

https://www.tapatalk.com/groups/thedianawerkcollective/redfeather-could-you-email-or-call-me-t13683.html

Good luck with your B21.

try this link

https://www.tapatalk.com/groups/thedianawerkcollective/detailed-step-by-step-48-52-54-tuning-instructions-t2878.html

It may be hard to locate a breech seal for your Chinese-made B21 rifle if you need one, assuming it takes the same breech seal as the also-Chinese-made SM 1000, which preceded it.  They take the same piston seal as the 48 et al, but not the same breech seal. 

In other words, don't remove the one that's in there when you do the other work unless you know you've got the right one to replace it with.  If you don't have another good breech seal to replace it with, try not to destroy the existing one.  Even if the seal leaves something to be desired, you might be able to make a shim out of thin sheet metal or thin plastic sheeting to put under the seal to provide a good seal at the breech.  Dental floss works as a last resort for such things, but that's what I try to reserve it for--a last resort.

In short, there may be nothing wrong with your breech seal, so 'don't fix it if it's not broken'.  Proceed on that basis and cross the other bridge if and when you come to it.

HTH.

http://air_guns.tripod.com/disassemble_b21.htm

Tonight I'm going to watch every youtube video on disassembly and tuning these and see if I think I can do it. 

More to follow. 

Thanks for the help so far, much appreciated. 

Thanks.  I watched the one you provided on the B21, and the five part series by Airgunners Edge on the RWS 48.  Is he here, by the way?  I learned a lot about how it comes apart from those and the links.  

Wow, doing it with a bar clamp, that looked a little scarey.  

Okay, a question.

My spring compressor needs some work to fit this one but there's clearly enough travel on the screw to do this.  I thought I was going to have to modify it.  

The videos of the Diana 48 show two pins, and he uses dummy pins.  The B21 only has one pin, and that video doesn't use dummy pins.  I'm about to make one just in case but wondered if anybody knew if it was needed.  

Now I need some advice.

I took it apart.  It was really not bad, except for a mishap with the spring compressor.  I've never used one before.  I thought I built a safe one, but I didn't.  It slipped sideways as I was backing off the compression, and the trigger block popped out.  It hit the wood block the lead screw was mounted on, not too hard or loud but startling.  I used a repurposed auto scissors jack part - dumb, should have just bought all-thread and did it right the first time.

Anyway, I don't see much obviously wrong, and I don't have enough experience with seals to know.  I'll try to attach photos.  The piston did not want to come out of the chamber.  I had to really force it, and when it came the piston seal was cocked half off it.  But when it finally gave I moved it sideways and maybe caught it on the lip.  It goes on and off the button easily now.  I don't know enough to evaluate the breech seal.

From here it looks like the breech seal is going to be OK.  Just leave it be and try not to damage it, as in scratch or nick it.

It sounds like the piston seal had kind of glued itself inside the chamber, which would explain why you had to force the piston to remove it, also why the seal came off of the piston (if I read that right).

Looking at your photos, now I remember that when I rebuilt my SM 1000 I didn't trust that black plastic spring guide you show that was also in my rifle, because it seemed pretty brittle stuff to me.  So, I bought a white cast Nylon one that fits the RWS 48, 52, and 54 to use instead, from Umarex USA, which I would highly suggest you do also (unless you already have a spare one lying around).

I also bought an ARH/Maccari piston seal:

http://www.airrifleheadquarters.com/catalog/item/251485/43075.htm

And one of his higher-than-factory-quality springs:

http://www.airrifleheadquarters.com/catalog/item/251488/10099208.htm

Or, this one for a little more power/velocity:

http://www.airrifleheadquarters.com/catalog/item/251488/8484943.htm

BTW, regarding the latter spring, because of the wording on the site, I'm not sure if you can buy one if you don't buy the full ZRT Kit or not.  If not, the first one I just listed will work.

If you can't afford one of those premium-quality springs, the factory spring will probably work OK, but for the small cost it's worth every penny.

He even offers a complete spring kit with spring and guides for your rifle:

http://www.airrifleheadquarters.com/catalog/item/251488/6962763.htm

When you go to lube the piston seal before assembly, you can use just a dab of his moly paste or just a drop or two of non-detergent SAE 30 motor oil, applied only to the SIDES of the seal (not the front).

I won't pretend that I just told you everything there is to know to get the most out of your project and the performance of your rifle.  There are things like spacers and grade 8 steel washers that can be added to give you the pinnacle of performance, and other places to put lubricants, but I'll leave the description of those things to others, together with their instructional posts and videos.

HTH a little.

Wow, thanks, that's awesome help.

Especially the links, I went to the site before but had a little trouble navigating.  

I don't want to do it the cheapest possible, I'll send for the kit.  Now that I've had one apart, I have a little more confidence.  Much of my shooting is the Diana 24, very low power and perfect for the basement.  It will likely need work at some point too.  

You're welcome.  Good call on the kit.

The trigger may also need some attention--it may be a little (or possibly a lot) stiff, if it was like mine.  I hear that a lot of them are that way.  I know a good bit about springer triggers, but IMO, taking the trigger on this rifle apart is not for the fainthearted.  So, instead, mixing some of that moly paste together with some of the non-detergent SAE 30 motor oil, then dripping 4 or 5 drops of the mixture down inside the trigger assembly with the trigger upside down, and shooting something like 10 or so pellets while the rifle is still inverted may help with that.  You can also blow a couple of good hard puffs of your breath down inside the trigger after you add the lube, but before you turn it upright again.  That should help distribute the lube. 

After that, when the rifle is upright again, simply wipe away any excess lube mix that dribbles out so it doesn't get all over the place, including on you.

 If you buy the spring from JM, one thing I would recommend is to pay the $1(or whatever small fee it is now) to have the spring "set". If you have never set a spring you'll thank me. Some may not consider it a big deal but to me it is a HUGE convenience.

Posted by: Bigbore

 If you buy the spring from JM, one thing I would recommend is to pay the $1(or whatever small fee it is now) to have the spring "set". If you have never set a spring you'll thank me. Some may not consider it a big deal but to me it is a HUGE convenience.

On the spring page it says the fee is $2.00.  I asked about it when I ordered and the return email said it's always included with the kit anyway. 

http://flyingdragonairrifles.org.  

Mike Melick will probably be your cheapest option if you want someone else to repair it.

David Enoch

They are a pretty bullet proof design, and not too hard to work on.  Springs, guides and seals that fit a Diana 48 will work well in this gun.  I cut my tuning teeth on just such a beast, and wound up with a very nice gun.  It was my first attempt at tuning a springer, and took some trial and error, but I learned a lot along the way.  I would say, Dive In!  What have you got to lose?

Posted by: DavidEnoch

http://flyingdragonairrifles.org.  

Mike Melick will probably be your cheapest option if you want someone else to repair it.

David Enoch

Thanks.

If I'd seen this first I'd probably have gone that route.

But the gun is apart, spread out on a table in the basement, and the tuning kit on order.  So for better or worse I'm committed to doing it myself.  I've already learned a ton about the inner workings of this.  

One that I've tried to take apart and failed is my Mark 1.  Low priority, but someday I'd like to have that working again too.  Still, now that I'm past the mid 60s, I'm trying to reduce the backlog of projects.  

I did succeed in resealing a Diana 6.  That was a royal pain in the butt to get back together, those fine thread screws and that recoil system, but it shot very well after.  Wish i still had it.  

Uh oh.  

While I'm waiting for the tune kit to arrive, I was looking at the trigger group to be sure how I'd insert the main pin again.

And I just had an Oh Cra moment, because there on the table was a tiny ball bearing, about half the size of a BB.  No idea where it came from or where it goes, but this can't be good.  

It's back together and it shoots.  

I don't know how hard yet, I'll dig out the chrony next weekend, but it is clearly much better than when I chrony'd it 10 years ago.  It hit a silhouette with a pretty good clang.  It's much smoother than I remember, the Maccari kit was a good choice. 

Things I learned:

DIY spring compressors have some limitations.  Better to buy a good one.  I didn't and regretted it.

Be careful not to lose any springs.  Especially ones you don't know are there.  There is no longer an automatic safety because I couldn't put that piece back in without the return spring.  

Iron sights.  I was hoping with the cataract surgery I could see them again.  Nope.  I might see if an aperture will work.  

Triggers.  Yeah, it's pretty rough.  I'll try adjusting it now that I know how.  

Thanks to everybody who helped.  And kudos to you who do this a lot; I found it a challenge.