Crosman 1377 losing some compression after 2 month's use
Select Gate
READ GTA FORUM RULES BEFORE POSTING
GTA Forum Help Desk
GTA Announcement Gate
Dealer Area
GRIP
AirgunWeb Airgun Videos
Airgun Repository of Knowledge
Vendors and Vendor Videos
AirGun Expo 2021
Airgun Expo 2022
Contests and Giveaways!!!
Welcome New Members
In Memoriam
GTA Contributing Members
Shot Show Videos
Hajimoto Productions
Airgun Detectives
Air Gun Gate
BB Guns and Such
"Bob and Lloyds Workshop"
American/U.S. Air Gun Gates
European/Asian Air Gun Gates
PCP/CO2/HPA Air Gun Gates "The Darkside"
Air Archery
Vintage Air Gun Gate
Air Guns And Related Accessories Review Gates
Hunting Gate
Machine Shop Talk & AG Parts Machining
3D printing and files
Buyer's, Seller's & Trader's Comments
Bargain Gate
Back Room
Target Shooting Discussion Gate
Target Match Rules
Shooting Match Gates
Field Target Gates
The Long Range Club
100 Yard Match
Discussions By States
Welcome,
Guest
. Please
login
or
register
.
Did you miss your
activation email
?
1 Hour
1 Day
1 Week
1 Month
Forever
Login with username, password and session length
Home
About
Help
Old GTA
Gallery
Search
Stats
Login
Register
Advertise Here
GTA
»
All Springer/NP/PCP Air Gun Discussion General
»
American/U.S. Air Gun Gates
»
Crosman-Benjamin Air Gun Gate
»
Crosman 1377 losing some compression after 2 month's use
« previous
next »
Print
Pages: [
1
]
Go Down
Share This!
Author
Topic: Crosman 1377 losing some compression after 2 month's use (Read 2016 times))
Alanheal
Marksman
Posts: 304
yes
Crosman 1377 losing some compression after 2 month's use
«
on:
March 02, 2019, 12:25:29 PM »
Greetings,
I bought a Crosman 1377 2 months's ago. Until today it would penetrate a soup can at 30 feet with 10 pumps. Today for some reason it felt easier to pump. Instead of penetrating the can it just dents it and ricochet's back at me.
Any idea what could be the problem and how to fix it?
Thanks!
Logged
Pennsylvania
mr007s
GTA Senior Contributor
Posts: 7265
Real Name: Ray
Re: Crosman 1377 losing some compression after 2 month's use
«
Reply #1 on:
March 02, 2019, 12:50:52 PM »
Are you placing a drop or two of Pellgun oil on the piston now and then? Also check if a leak has developed from the transfer port. I suspect the pump seal needs oil.
Logged
Hickory, North Carolina
mr007s,,,,,Life is Good
Half of me wants a cold beer
The other half wants two
Alanheal
Marksman
Posts: 304
yes
Re: Crosman 1377 losing some compression after 2 month's use
«
Reply #2 on:
March 02, 2019, 02:06:10 PM »
RE: Are you placing a drop or two of Pellgun oil on the piston now and then? Also check if a leak has developed from the transfer port. I suspect the pump seal needs oil.
I put a drop of oil on the piston yesterday and the next day the gun lost some compression. That's the only thing that changed. Could that have caused the problem? If so, how to repair? (by transfer port, do you mean the breech?)
Logged
Pennsylvania
mr007s
GTA Senior Contributor
Posts: 7265
Real Name: Ray
Re: Crosman 1377 losing some compression after 2 month's use
«
Reply #3 on:
March 02, 2019, 02:31:42 PM »
yes. the breech
Logged
Hickory, North Carolina
mr007s,,,,,Life is Good
Half of me wants a cold beer
The other half wants two
Alanheal
Marksman
Posts: 304
yes
Re: Crosman 1377 losing some compression after 2 month's use
«
Reply #4 on:
March 02, 2019, 10:22:02 PM »
There's no leak from the breech. There's still power in it, but not enough to pierce a soup can. It went south over night. Could my one drop of oil have messed something up? I put a drop after each 250- 300 shots. Just had to lube it twice since I bought it. Enjoyed the pistol very much until now. If the problem is the valve, does that require a lot of disassembly to get to?
Thanks
Logged
Pennsylvania
mr007s
GTA Senior Contributor
Posts: 7265
Real Name: Ray
Re: Crosman 1377 losing some compression after 2 month's use
«
Reply #5 on:
March 02, 2019, 11:27:49 PM »
Have you tried more than 10 pumps? I assume you have a stock piston and valve and not the flat top set up?
The piston seal may need more than one or two drops. Extend the pumping linkage like you are pumping. When it is fully extended turn the gun over so you can look in the slot and see the piston, you may not see the cup but put 6 or so drops around the piston and work the linkage back and forth to help move the oil to the seal. If that dont bring it back up to pressure you may need to tear it down ans inspect some parts. Plenty of info on how to on this site and YouTube. Hang in there , its not very hard to fix one of these.
Logged
Hickory, North Carolina
mr007s,,,,,Life is Good
Half of me wants a cold beer
The other half wants two
Wayne52
GTA Senior Contributor
Posts: 31841
Gone but not forgotten!!!
Real Name: Wayne
Re: Crosman 1377 losing some compression after 2 month's use
«
Reply #6 on:
March 02, 2019, 11:36:51 PM »
Pellgun oil does pretty good for rejuvenating stuff but it sounds like something is amiss, I haven't owned a pumper other than my Sheridan for years and bought thay in 77 and still going strong. I've just gotten so use taking anything like that apart for a look see myself. I never have sent an airgun back for warranty work because I enjoy the tinkering as well.
Logged
USA, MI, Grand Rapids
HHDSUPCOM Cam Rahn Bay VN 71-72
My F10 Shoebox rocks
Stinger177
Favorite sport - Anything that requires a helmet.
GTA Senior Contributor
Posts: 3449
yes
Real Name: Dennis
Re: Crosman 1377 losing some compression after 2 month's use
«
Reply #7 on:
March 02, 2019, 11:43:41 PM »
To answer your last question first, yes. The valve is pretty much the
last
thing to be removed from the compression tube during a rebuild.
You didn't say if your gun was brand new or not. I wouldn't expect a new gun to lose compression that soon, however a loose breech screw could cause a leak at the transfer port. The transfer port is a short rubber or poly tube between the valve and the bottom of the barrel, just ahead of where the pellet is pushed forward by the bolt. If the breech screw is loose that seal will leak.
Two things I would do, in this order:
1. Do the tissue test. Place one leaf of toilet paper over the breech and let it drape along the sides. Fire a pellet and watch carefully if the tissue puffs up or out. Brace the gun on something so that movement of the gun isn't the cause of the tissue movement. If the tissue moves or puffs, then check the tightness of the breech screw (see step 2).
2. Tighten the breech screw by pulling back the bolt and look right where you drop the pellet in to load it. The screw should be barely visible down inside a hole. If you don't see it, you have an older style gun where that screw is under the bolt.
Check to see which gun you have and if you can't find that screw, report back.
BTW, that screw should be a 0.05" hex. It's very easy to strip that screw, so be careful. Most of us modder's replace it with a torx.
Let us know what you find out.
Dennis
«
Last Edit: March 02, 2019, 11:47:48 PM by Stinger177
»
Logged
Denver, CO, USA, North America, Earth, Sol, Milky Way ... - .. -. --. . .-. .---- --... --... / - --- / -- --- - .... . .-. / ... .... .. .--. .-.-.- / .--. .-.. . .- ... . / -.-. --- -- . / -... .- -.-. -.- / .- -. -.. / --. . - / -- . .-.-.-
You can view my gun list
here
Alanheal
Marksman
Posts: 304
yes
Re: Crosman 1377 losing some compression after 2 month's use
«
Reply #8 on:
March 03, 2019, 01:29:51 PM »
Hi Dennis,
I did the tissue test and saw no leaking.
2. The breech screw is in as far as it could go.
I just realized the gun is still returnable, so will exchange it for another. I'd try fixing it but haven't those skills.
I'm wondering if it's safer to never oil a gun until its squeaking and obviously needs it, rather than doing it after so many shots. I believe my drop of oil the night before messed it up in some way.
Thanks for the suggestions. I know that much more about the gun now.
Dennis
Logged
Pennsylvania
Stinger177
Favorite sport - Anything that requires a helmet.
GTA Senior Contributor
Posts: 3449
yes
Real Name: Dennis
Re: Crosman 1377 losing some compression after 2 month's use
«
Reply #9 on:
March 03, 2019, 02:06:53 PM »
Since the gun is new, sending it back for exchange is definitely the best course of action. Don't mention that you
think
you over lubed it. Don't mention anything (except the main issue of course) unless they ask you, and then only say that you lubed it as recommended, which is what you did.
Just curious..from whom did you purchase it?
Let us know how it turns out, even though it may be some time.
Dennis
Logged
Denver, CO, USA, North America, Earth, Sol, Milky Way ... - .. -. --. . .-. .---- --... --... / - --- / -- --- - .... . .-. / ... .... .. .--. .-.-.- / .--. .-.. . .- ... . / -.-. --- -- . / -... .- -.-. -.- / .- -. -.. / --. . - / -- . .-.-.-
You can view my gun list
here
Back_Roads
I Got A 15 Pump BB Gun :) BB Guns Got Much More Complicated :)
GTA Senior Contributor
Posts: 15930
1st Edition Crosman 760 Pump Master
Real Name: James Seiler
Re: Crosman 1377 losing some compression after 2 month's use
«
Reply #10 on:
March 03, 2019, 02:40:52 PM »
About a year ago I bought a 2100 Legacy from Walmart, with in 10 shots it quit building pressure, so back to walmart it went, got another off the shelf and no issues since.
Logged
Wisconsin Collins Hunters Paradise" There's a Sign in Town to Prove It
https://www.zeemaps.com/group=962067
Member Map.
[smg id=6202]
https://www.youtube.com/channel/UC3hMPAjvTtuu7DoNzBZzuKQ?view_as=subscriber
https://youtu.be/PZvrk-L6Gzg?list=PLASJo4rBxMIkewLOlcMHC56YM0BpdR6cb
https://youtu.be/bk_N1l7H2F4?list=PLASJo4rBxMIk6BNY6V_tZahlmptN6qBlk
Alanheal
Marksman
Posts: 304
yes
Re: Crosman 1377 losing some compression after 2 month's use
«
Reply #11 on:
March 03, 2019, 10:51:26 PM »
Thanks for the suggestions Dennis. I bought it from Amazon.com on Amazon prime, so no problem exchanging it. I don't recall who the actual retailer was. Looking forward to shooting the 1377again. Could use a smoother trigger. I managed to compress the spring a bit so the trigger was lighter, but it was still "crunchy" .
Logged
Pennsylvania
Stinger177
Favorite sport - Anything that requires a helmet.
GTA Senior Contributor
Posts: 3449
yes
Real Name: Dennis
Re: Crosman 1377 losing some compression after 2 month's use
«
Reply #12 on:
March 03, 2019, 11:40:58 PM »
Trigger mods and improvements are so easy to do on those guns. All you need to do is remove the grip panels. Compressing that spring is just one of them, but I replace the spring altogether.
I can give you some tips, but most of them are all over the net. Some are worth doing, but some are outrageous (and outrageously expensive). Simple polishing of the contact points of the trigger and sear will help a lot. Since your gun is new, I'd order some parts from Crosman to play around with. That way, if you need to send it back again (let's hope not) you can put the original parts back in to maintain the warranty. NOTE - If you do call Crosman, have your part numbers ready. They will not look them up for you. A parts list and owners manual can be downloaded from here:
https://support.crosman.com/hc/en-us/articles/203542980-1377-Owner-s-Manual-EVP-1998-Present-
Many other people here at the GTA will have good ideas as well but I'd start with doing a little research on your own. Just do a Google search for 1377 trigger modifications. I most often switch immediately to "images" and see what's interesting, then click on that link for more.
Come back when you get your replacement and we can go from there. In the meantime, I'll try to remember to take some pics of my own mods to send to you, but right now I'm waiting on a new laptop to replace the one that just went down. should be here Wednesday.
Dennis
Logged
Denver, CO, USA, North America, Earth, Sol, Milky Way ... - .. -. --. . .-. .---- --... --... / - --- / -- --- - .... . .-. / ... .... .. .--. .-.-.- / .--. .-.. . .- ... . / -.-. --- -- . / -... .- -.-. -.- / .- -. -.. / --. . - / -- . .-.-.-
You can view my gun list
here
Alanheal
Marksman
Posts: 304
yes
Re: Crosman 1377 losing some compression after 2 month's use
«
Reply #13 on:
March 04, 2019, 12:12:08 PM »
Thanks Dennis. I'll google and Youtube it. Good luck with the new laptop!
Logged
Pennsylvania
rangerfredbob
Sharp Shooter
Posts: 882
yes
Real Name: Scott
Re: Crosman 1377 losing some compression after 2 month's use
«
Reply #14 on:
March 09, 2019, 01:31:19 AM »
disassembly is simple on these things, if you get one of the cheap precision screwdriver kits from Harbor Freight like
THIS
it should be near enough to get the thing apart, from there all you need is something that's about 3/16" and a hammer to get the roll pin out for the pump pivot... I have that $5 screwdriver kit and it was dang near enough to get my Marauder rifle apart the other day... For the front breech screw use the T05 torx bit not one of the allen bits, the torx bites better and has a lower chance of stripping it out...
That said, an exchange should get you going, it shouldn't have given up that easy... it was probably something simple like some debris in the check valve or in the piston (drug into the check valve by the oil, not your fault unless you dropped it in sand or something after oiling...)
Logged
Oregon, Salem
Two Beeman RS2's one in .22 and one in .177, Marksman 2004 (Beeman P17)
Cummins B3 .177, Industry B3-1 .22 and similar pistol
Crosman 1322, 1377 times 2 (.22 new, .177 from mid '90's second .177 is a project), and 2289G
Crosman 66 Powermaster, 2240, 1077, and 357
Daisy Powerline 990 and 880
Benjamin Marauder .22
Alanheal
Marksman
Posts: 304
yes
Re: Crosman 1377 losing some compression after 2 month's use
«
Reply #15 on:
March 09, 2019, 07:22:47 AM »
RE: disassembly is simple on these things, if you get one of the cheap precision screwdriver kits from Harbor Freight like THIS .....................................
Thanks for the tips! The exchange of 1377's went smoothly on Amazon prime and the new one has full power. The rear sight is lined up such that there's no room to lower the aim if I ever need to, as it's already as low as it can go. However it's on target at the moment, so no problem. ( For future reference, is that fixable? I thought of filing that rear site slit to lengthen it, but there's not much metal to work with.)
Logged
Pennsylvania
Print
Pages: [
1
]
Go Up
« previous
next »
GTA
»
All Springer/NP/PCP Air Gun Discussion General
»
American/U.S. Air Gun Gates
»
Crosman-Benjamin Air Gun Gate
»
Crosman 1377 losing some compression after 2 month's use