Crossman 140 Trigger Safety Problem
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Crossman 140 Trigger Safety Problem
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Topic: Crossman 140 Trigger Safety Problem (Read 1112 times))
dmassom
Shooter
Posts: 7
yes
Real Name: Del
Crossman 140 Trigger Safety Problem
«
on:
December 06, 2018, 06:26:19 PM »
The safety on my Crossman 140 stopped functioning. Sometimes after pumping the gun it would fire as soon as the safety was turned from on to off. I've resealed the gun and now it no longer fires when the safety is turned from on to off, but the trigger can be pulled, firing the gun, with the safety ON. I took the trigger assembly apart and inspected the trigger and safety assembly; there are no signs of wear but the Safety Rod (p/n 1400-010) appears to be about 0.070" to short which allows the trigger to be operated even when the safety is on. I made a new Safety Rod, making it about 0.070" longer than the original; the safety now functions correctly. I don't understand this since there are no signs of wear or any thing broken or any missing parts. Has any one-else experienced this problem and/or have an explanation as to why it has occurred?
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USA, Indiana, Valparaiso
TF89
Expert
Posts: 1016
Real Name: Dave
Re: Crossman 140 Trigger Safety Problem
«
Reply #1 on:
December 08, 2018, 03:15:34 PM »
It is all about checking fit. The trigger sear on those fits up between sear block 140-17 and tube plug 140-14. There are a number of factors here.
*Edit as I forgot about this aspect.* The stock and the action need to be tighten together securely. If the action is loose fitting in the stock the gun will randomly fire. This is why Crosman changed the nut that holds the two together.
1) The sear can be worn
2) The sear block can be worn
3) The trigger spring is weak (not likely as they are very stiff)
4) The action is not fitting into the stock well and the trigger sear is not able to extend far enough into the air tube.
5) The tube plug pin 140-30-A (This is what holds the breech to the air tube, and rear breech screw 140-13 screws into it)sometimes will hit the stock and prevent the action from sitting into the stock.
6) I guess I should add one here as I think about it. The steel pin in the stock that holds the trigger could be bent.
The trigger sear on those really needs to fit into the assembly as far as possible or it can randomly fire. The trigger is held in place with a steel pin through the stock. Either the the trigger has to be moved closer to the action or the action needs to be moved closer to the trigger. I recommend just sanding the air tube slot to lower the action into the stock.
Don't forget to check and make sure that the tube plug pin 140-30-A is not hitting the stock.
On mine I took a dowel the same diameter (or close) as the tube 140-1 and wrapped sandpaper around it and sanded the slot in the stock until it was unformed. Just take your time, checking fit often. I think you will find that the slot in the stock (where the air tube sits) will not be even or uniform. Mine required some heavy grit to start and then I finished up with 220 and then I sealed the newly exposed wood to reduce swelling from moisture. After sanding the trigger sear now fits deeply into the sear block and no longer randomly fires.
Still as a safety caution, I pump and then I load the pellet. When I first received the model 140 it would sometimes fire without warning. Now that I worked the stock, the action and tube are a uniform fit.
«
Last Edit: December 08, 2018, 03:42:50 PM by TF89
»
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Benjamin Pistol (P-rod)
Benjamin Discovery .22, BNM breech/shroud (35 FPE with 20" barrel)
Crosman 400
Crosman 140 with 2260 top end
Remington NPSS .177
Crosman 1322, 14” barrel, partial mods, flat top piston
Beeman P17
XISICO XS-12 .177 Prototype trigger
HW25 (1968)
dmassom
Shooter
Posts: 7
yes
Real Name: Del
Re: Crossman 140 Trigger Safety Problem
«
Reply #2 on:
December 09, 2018, 03:13:49 PM »
Thanks TF89, I'll check the fit. Mine is a later model with the four-day trigger assembly with the safety in the trigger guard. The action is tight in the stock.
The trigger appears to be going all the way in and there is approx. 0.075" gap between the trigger and the Safety Rod which allows the trigger to be actuated even with the safety ON.
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USA, Indiana, Valparaiso
TF89
Expert
Posts: 1016
Real Name: Dave
Re: Crossman 140 Trigger Safety Problem
«
Reply #3 on:
December 09, 2018, 05:23:59 PM »
Gotcha. Maybe that info will help someone else. The part that confuses is me where your say the gun will fire when you take the safety off or if you bump it. I don't see how resealing relates to the trigger. The sear wedges between the the two blocks and if the sear is rounded off and/or not far enough in can and will slip out resulting the valve dumping.
Regardless, sounds like you resolved the issue of the safety. Could be the factory tech was thinking about something and
QC missed it.
«
Last Edit: December 09, 2018, 05:27:22 PM by TF89
»
Logged
Benjamin Pistol (P-rod)
Benjamin Discovery .22, BNM breech/shroud (35 FPE with 20" barrel)
Crosman 400
Crosman 140 with 2260 top end
Remington NPSS .177
Crosman 1322, 14” barrel, partial mods, flat top piston
Beeman P17
XISICO XS-12 .177 Prototype trigger
HW25 (1968)
dmassom
Shooter
Posts: 7
yes
Real Name: Del
Re: Crossman 140 Trigger Safety Problem
«
Reply #4 on:
December 10, 2018, 12:55:05 PM »
I bought this gun new circa 1968 and it worked fine for many years; I can't see how it would have functioned for several years if the problem was a manufacturing or QC problem.
I'll continue it research the issue.
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USA, Indiana, Valparaiso
jab
Plinker
Posts: 263
yes
Real Name: john
Re: Crossman 140 Trigger Safety Problem
«
Reply #5 on:
December 10, 2018, 01:59:14 PM »
safety lever nub wore down ? pn# 1400ao041
«
Last Edit: December 11, 2018, 02:08:46 AM by jab
»
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Oregon
ped
Sharp Shooter
Posts: 548
yes
Re: Crossman 140 Trigger Safety Problem
«
Reply #6 on:
December 10, 2018, 02:18:55 PM »
worn trigger possibly or release block
I had one that would fire by it's self and fitting a new trigger solved it
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uk
Flex
Shooter
Posts: 40
Don't want to, don't have to, I'm retired!
Re: Crossman 140 Trigger Safety Problem
«
Reply #7 on:
January 02, 2019, 02:30:02 PM »
So, is this "Crosman 140 Trigger Safety Problem" under control yet?
Based on the OP's description, I'm thinking that the trigger mechanism on his 140 looks like this:
Worn components could definitely be an issue but if the change in function happened abruptly, I'd guess that a component may have broken. A weak trigger spring was suggested earlier but dismissed as that spring is generally a stiff one. It provides the force that holds the trigger sear against the sear block and keeps the gun from firing until the trigger is pulled. My first thought is that the trigger spring has broken and is not providing enough back pressure on the trigger to maintain solid contact between the trigger sear and the sear block. Another possibility is that the part of the trigger mechanism casting (either the left or the right side) that holds the trigger pivot pin in place has "ovaled" out or broken. The latter could occur if excess pressure was applied to the trigger with the safety engaged. I'd say have a look at these components of the trigger mechanism.
Flex
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A little of what you fancy does you good (or so it should). JT
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Crossman 140 Trigger Safety Problem