Breech seal question for Diana 54

[Pistonpellet]

Hi .  When replacing a breech seal on a Diana 54 , does the flat side go down in the breech first or the cup side? I’m pretty sure  flat  side  but just want to make sure as never replaced a breech seal before. Will it have to be lubed to get it down in place?Ive  read that a 3mm dowel can be used to push it down in place. Is this correct?
Thanks
Al

[Roadworthy]

I never thought about it, I just set it in place flat side down.  If you can push it into place cocking the gun will take care of the final seating.

[cjtamu]

Flat side down. Can tap into place with a 3/8” or similar sized dowel. No lube needed even with the ARH seal which is a tight fit.

[Pistonpellet]

Got it!
Roadworthy and cjtamu, thanks for taking  time to advise me on this. I did pop it in with a tap from a 3/8 “wooden dowel . I also put a small bit of moly lube on the bottom edge but now realize I didn’t need it.
Just as a note , the breech seal that the factory had installed was for the newer 2022 models. Mine was built in Dec 2018.
It is much different. It’s amazing how such a small thing can pretty well make a new gun pretty well un usable.

[cjtamu]

Got it!
Roadworthy and cjtamu, thanks for taking  time to advise me on this. I did pop it in with a tap from a 3/8 “wooden dowel . I also put a small bit of moly lube on the bottom edge but now realize I didn’t need it.
Just as a note , the breech seal that the factory had installed was for the newer 2022 models. Mine was built in Dec 2018.
It is much different. It’s amazing how such a small thing can pretty well make a new gun pretty well un usable.

Glad you got it sorted. Yes, it’s amazing. Bought a gently used 56 T/H recently. Came to me making 9 FPE. Replaced breech seal and it went to 18. Heat good things about the new OEM breech seals but yet to lay hands on one. Be sure the cocking arm is adjusted properly. Link below to old Tapatalk thread helped me. Thread here where Hector discusses also, I’ll find later.

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

[Pistonpellet]

Cjtamu,
That link you sent me is what I used as a guide to dismantle the 54. It wasn’t to difficult except for re installing the cocking arm with those two thin shims on the inside. Must be a trick to it but I haven’t found it yet.
I am in contact with Hector  and he is helping my situation.
When adjusting the cocking leaver , Hector says it should be 2” when it starts to put pressure on the seal. Where exactly do you measure the 2” from?  I assume maybe from the middle of the rubber  end on the cocking arm to the receiver. Is this correct? I have the pull rod complete hinge screwed clockwise to the max and the distance is about 2” . Hector had suggested I back it of counter clockwise a 1/2 turn but that puts the distance quite a bit further, 4 + “   actually bending the pull rod. Don’t think this is right. The breech seal is definitely all the way in .
Any clarification on this would be greatly appreciated.
Thanks
 Al

[cjtamu]

Cjtamu,
That link you sent me is what I used as a guide to dismantle the 54. It wasn’t to difficult except for re installing the cocking arm with those two thin shims on the inside. Must be a trick to it but I haven’t found it yet.
I am in contact with Hector  and he is helping my situation.
When adjusting the cocking leaver , Hector says it should be 2” when it starts to put pressure on the seal. Where exactly do you measure the 2” from?  I assume maybe from the middle of the rubber  end on the cocking arm to the receiver. Is this correct? I have the pull rod complete hinge screwed clockwise to the max and the distance is about 2” . Hector had suggested I back it of counter clockwise a 1/2 turn but that puts the distance quite a bit further, 4 + “   actually bending the pull rod. Don’t think this is right. The breech seal is definitely all the way in .
Any clarification on this would be greatly appreciated.
Thanks
 Al

I asked Steve Herr and he told me to measure from where the taper on cocking arms starts. Basically right at the rubber piece. But, I think that distance was 1 1/4” to 1 1/2”. 2” sounds like maybe from end of the arm. Mine is set where if I back off another 1/2 turn the arm doesn’t snap shut and stay in place as it should. That put me very close on measurements.

[Pistonpellet]

Ok, thanks for  the info.  Good to have someone else’s opinion who knows more about this than me.
Does the  pull rod on your 56  have a slight bend in it when it’s closed down on the receiver? It’s not a very sold piece to begin with. My 54 had a slight bend when I first received it. Don’t think it was adjuster correctly from the factory. Maybe the wrong seal situation had something to do with it.
I assume there has to be some moderate bend to it when it snaps shut on its own.

[Toxylon]

Yes, a slight bend is needed.

[cjtamu]

Yes, the cocking rod has a slight bend to it. Not sure what you mean by the wrong seal. Did they upgrade to the D460 seal? Would be a blue, softer seal. Both Hector and Nitrocrushr told me it’s a good seal for the 54/56. Pic of it in article linked below. Considering setting up my swamp cooler and EZ Up and shooting mine a little today. We’ll see. This kind of heat just wears me out.

https://www.ctcustomairguns.com/hectors-airgun-blog/the-020-cal-diana-54-project

[Pistonpellet]

Pretty hot down your way for sure. We rarely hit the high nineties up here in NS. Canada.
Yes, that describes the seal that came out of my gun, blue and soft. It didn’t work very well for me. It was pretty well torn in half. Hector did explain what happened to it as I sent him some pictures.  Just finished modifying my  homemade 10” C  clam compressor in order to get the  spring back in with , new seal and putting  in Vortek kit . Just hope I can get the cocking arm with the two little washers back in without to much stress. After struggling for over half hour the first time everything just  suddenly dropped in, not idea why. Don’t know why Diana makes the tolerances so tight.

[cjtamu]

There’s a trick to it. Seems like I opened the arm a little and gave me enough purchase to drop right in. Kim was born and raised not too far from you in NB. Got the weather reports from her mom last week, 47 degrees F and rain sounded like heaven ha ha ha.

[Pistonpellet]

NB just next door. I  am originally from Moncton NB. Where in NB is Kim from?
Got some good news about the Diana 54. The cocking arm somehow  with little washers  just  somehow dropped in place  again. Only took about 20 min this time. I enjoyed taking the gun apart and re assembling it and  wasn’t to difficult.
The gun now has lots of power. I dropped in a PG4 tune kit. Only remaining  issue  is the POI and POA , with iron sights  or  optically centered scope , are  not close at any distance . Hector Medina has offered to correct it for me. Its a matter of bending the barrel  and I don’t feel confident doing that procedure.
Hope your weather is cooling of a bit down there.

[cjtamu]

No way. Kim is from Moncton. Her mom was born and raised there, she’s in Riverview now. Small world. We’re hoping to be up there next year.

[Pistonpellet]

I’ll bet I might know Kim’s Mon. What high school did she go  to and what years? I’m most likely much older than you. I graduated in 1970.
It is a small word for sure.

[cjtamu]

I’ll bet I might know Kim’s Mon. What high school did she go  to and what years? I’m most likely much older than you. I graduated in 1970.
It is a small word for sure.

Moncton High. Sent you a PM.

[HectorMedina]

My GrandMa used to say: "It's not that the world is small, it's that there is few of us in the real aristocracy"

;-)





HM

[cjtamu]

My GrandMa used to say: "It's not that the world is small, it's that there is few of us in the real aristocracy"

;-)



HM

Member here from Ontario who says, “Small world, wouldn’t want to paint it”. Very true.