GTA
Airguns by Make and Model => Benjamin Airguns => Topic started by: DonH on August 08, 2014, 10:17:45 PM
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Hi, I have a Titan that doesn't lock up that well. Bump the bottom of the stock with my hand and it pops open pretty easy.
How does one fix it? Thanks. Don
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I just replaced my Titan lock up today. (alive jam) Sometimes the spring gets weak. I cut a piece of oak and clamped it to the gun with padded vise-grips. Then used a squeeze clamp to push the jam in. Then it's easy to tap the sleeve out the other side and slide the jam out and replace the spring. All can be ordered from Crosman.
Jam spring B15-01-2A $1.15
Alive Jam BT9M22-01-5 $2.60
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While you are doing that, replace the plastic washers with Brass ones like you see in his pictures...
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You can replace the weak spring with another weak spring from Crosman, it may help slightly. If you want to really fix the issue, you need to cut back the channel in the alive jam to let it come out further and engage the lockup pin better. Then a small shim behind the spring to regain preload, and then put a second spring from a hardware store inside of the original. After all that you will have a gun that sort of locks up tight. With the alive jam mod, shimmed bronze bearings for the pivot, and trigger bearing I've got my Fury 2 shooting .3" at 20 yards-- very happy and done with mods.
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Sprungout is 100 % right. I could tell very little difference with the new spring and jam. If I understand correctly this picture should show how to fix......
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Thanks a lot guys! That makes a lot of sense.
Thanks again. Don
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The other issue is that Crosman went to a weaker setup in the newer guns with the lockup pin vs. a lockup chisel detent. Yet another cost cutting measure and accuracy hurter. I think I spent about 8 bux to get the gun from a 1.5" @20 yard shooter to a sub .5" @20... absolutely ridiculous that Crosman can't spend a few dollars more to make guns that people will rave about and increase their sales. Also, I had to shim the bronze bearings for the barrel pivot to get proper tension--aka they were too thin.
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FYI you can buy the chisel detent from Crosman. It's shown on the EVP of several guns and so far all the Crosman/Benji compression tubes I've seen have a hole for it, even the Trail NP pistol. I got a couple last year but haven't used them yet.
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The other issue is that Crosman went to a weaker setup in the newer guns with the lockup pin vs. a lockup chisel detent. Yet another cost cutting measure and accuracy hurter. I think I spent about 8 bux to get the gun from a 1.5" @20 yard shooter to a sub .5" @20... absolutely ridiculous that Crosman can't spend a few dollars more to make guns that people will rave about and increase their sales. Also, I had to shim the bronze bearings for the barrel pivot to get proper tension--aka they were too thin.
Max, how thin is to thin(bushings)? The ones I did are snug, no side play. I bumped the stock pretty firm and it just moves down a little. Defintely better.
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I believe the standard for bushing tightness is just snug enough to hold the barrel from falling down when out of the stock(opinions vary). The problem with mine was that the shoulder of the pivot bolt was bottoming out before it pulled the forks together enough. Then I shimmed the bronze bearings and was able to get it tight enough before the bolt bottomed. There normally is an empty hole in the receiver where the old style lockup detent went. Supposedly the old parts can be switched in for better lockup, but nobody seems to know what actually holds that detent in? The only thing near that area to secure it are the stock screws...
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Mendoza has long used the pin instead of a chisel detent. I guess this is an American rebranding of a Chinese copy of a Mexican design. At least they didn't copy another Mendoza feature - a pin instead of the pivot bolt. No way to tighten up the compression tube yoke.
I installed a setscrew on both my Titan and my G1. I drilled and tapped lengthwise down the left side of the yoke. The setscrew bears against the pivot bolt head to keep it from loosening.
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There normally is an empty hole in the receiver where the old style lockup detent went. Supposedly the old parts can be switched in for better lockup, but nobody seems to know what actually holds that detent in? The only thing near that area to secure it are the stock screws...
It's been months since I looked at the parts but it seemed to me like the chisel would just be pressed into the hole. The hard part would be making sure it was aligned with the jam pin I think. Must use a jig in the factory.