Benjamin Newb Attempts Minor Modifications and Fixes to Benjamin Bulldog .357

[Ezana4CE]

I’ve identified the source of the leak. The fill nipple (the lower piece with the hex shaped fitting) feels pretty snug, but I can still see threads in the gap where the bubbles are coming from. I don’t want to put too much torque on it. I’m wondering if placing an o-ring between the fill nipple and the fill nipple adapter would help. Although the schematic doesn’t call for one to be placed at the junction between these two parts. 

I’ll try removing the nipple once more to see if I left any Teflon tape in the threads or cross threaded it when I put it back in last time. I have to get to the bottom of this leak. 

 

[Ezana4CE]

Ok so I’ve cleaned this area as best I could. There were a few small remnants of Teflon tape in the fill nipple adapter threads and I removed them with tweezers. 

After cleaning the threads up I placed a light coat of silicone oil on the threads. It doesn’t appear that it had been crossed threaded, nor did it feel like it had been when removing or replacing the nipple. After applying a light coat of silicone oil I hand tightened the nipple into the adapter until I couldn’t turn it anymore. Then I snugged down with a crescent wrench This time I filled it BEFORE reassembling the rifle. I looked good until the rifle’s pressure gauge read around 2000 psi. That’s when I began to hear that slow and steady hiss of air escaping. The reservoir went from 2000 psi to around 300 psi in 31 minutes. Time to talk to the manufacturer. This rifle has been leaking air since the day I got it. Now it’s leaking air faster and I’m out of ideas. Hopefully I can get some functional replacement parts from Crossman. Hopefully this thread helps others at some point. Thanks to all who chimed in. Special thanks to @bthurman for checking with me periodically, providing valuable info, and o-rings that we thought may be the issue initially. I really appreciate the assistance.

 

[Ezana4CE]

Problem solved!! I spoke with Brian at Veradium Air again this evening and we got it worked out. The solution was Teflon tape after all. It appears that he or I misunderstood the other. I applied the tape around the threads of the fill port nipple, screwed it back into the nipple adapter, gassed her up, and viola! The leak is no more!! It appears that there may have been a QC issue with Crossman when the Bulldog came from the factory. I contacted them earlier to get more info. The way it was leaking I thought there should have been an o-ring or something there and Brian confirmed that something other than an o-ring should’ve been placed on the threads from the factory. I finally get to shoot her again! Thanks again @bthurman. I hope he’s not tired of me. This man has been really helpful and supportive of me gaining a better understanding of this rifle and trying to troubleshoot my issues. 

 

[Ezana4CE]

After testing yesterday my Bulldog still shoots like a champ! Unfortunately a new problem arose. Now my shroud mount is sliding with the recoil. 

I tried searching for info in posts and via a search engine about this issue, but haven’t found anything yet. I have no idea what could have caused this. The mount always had a little play in it as far as slight side-to-side movement on the barrel, but I don’t recall it sliding forward like this. I have an idea for a temporary fix, but I’d like to know what caused this to happen. I noticed this gap after emptying a mag when I went to remove it. There are two screw holes atop the mount, the sliver screw atop the around screws into one hold to secure the back of the shroud to the shroud mount. I have no idea what the other hole is for. I’ve never used it and it has been empty since I purchased this rifle. 

 

[bthurman]

for tbis one the set screw in back hole is not set against barrel.

1. remove shroud screw

2 slide shroud a little foreward to xpose the block

there are 2 threaded holes the front one is.used to hold shroud screw. the back one next to receiver has a set screw in it. push block back against receiver and tighten down set screw it should park in the slot on barrel.

slide shroud back i stall shroud screw. 

 

[Ezana4CE]

@bthurman I’m not sure that I ever had a set screw to secure the shroud mount to the barrel in that second hole. I recall wondering what the second hole was used for the first time I saw the two holes in the shroud mount. With your explanation I can understand the schematic better. Thank you. It appears to show a set screw for the first hole to the rear. It’s listed as “part number R3571-084 set screw #8-32 X .250, DOG PT. Qty 1.” That’s “Item NO. 24” on the “Main Assembly Parts List.” Number 22 is the “Mount, Shroud.” I will look for one at the hardware store.

*edit note - Shortly after this posted I was contacted by support concerning replacement parts. 

 

[Ezana4CE]

Found the correct sized set screw at The Home Depot and it cost me $0.90 for two.

Went to secure the shroud mount but it wouldn’t screw down far enough to touch the top of the barrel. 

 
Then I thought maybe the threads weren’t tapped all the way through or something. So I tried to see how far I could screw a hex head screw of the same size, but longer than the set screw. I got the same result. At this point I was a bit frustrated so I screw the set screw into the hole that’s used to secure the shroud and it screwed down to the barrel securing the shroud mount preventing any movement. Then I tried screwing the shroud screw in the same hole on top of the set screw, but by the time it reached the set screw it was protruding up too far on top of the shroud. So I removed them both. While removing the set screw I noticed how far down it was situated in the shroud mount. It was at this point that I took my allen wrench and fished around in the first hole. That’s when I realized there actually was a set screw there the entire time. It must have vibrated loose in transit or while shooting. I didn’t see it because it is small, black, and Ihad not thought to look down into the hole with a light.

I didn’t think it was in there to begin with because I always remembered my shroud mount having play in it.

After feeling a little foolish I was able to situate the shroud mount correctly and reaffix the shroud. In my defense the other three set screws I’ve encountered in this rifle sit flush making the hexoganal sockets easily visible. Either way not seeing it was my mistake. Seems good to go now. Per usual Brian was right again. 

 

[Ezana4CE]

After applying the Teflon tape it appears that a slow leak has developed again. I’ve done all that I can think to do so I contacted Crossman via their site and have been in correspondence with a representative from Velocity Outdoor. It seems that Crossman is under the Velocity umbrella along with several other companies. The representative I’ve been communicating with has sent replacement parts under my warranty. I’m hoping that the replacement valve assembly doesn’t have the same issue as the one that’s currently installed. I intend to update this post when the parts arrive. 

 

[Ezana4CE]

Got replacement parts and a little time. Will probably change my fill port assembly tonight. To fix this leak I have to figure out the best way to remove and replace the fill nipple adapter. It’s round with the exception of the notch seen at the top of the cylinder. I have to figure out how to grip it without bending it or messing it up. Whatever that black stuff is on the fill nipple threads, I hope it helps seal the two parts so that no air leaks.

 

[Ezana4CE]

Finally got around to swapping out fill port assemblies. Let’s see how it holds air overnight. 

Once the reservoir cooled after filling it looks like I lost 100psi. Tested suspected areas for leaks with soapy water and didn’t see any bubbling. If it continues to leak the only other area I can think to check is the threads on the manometer. 

I’ll check the pressure again in the morning

 

[Ezana4CE]

Still leaking, but at a slower rate than before. I lost 500 psi in 11 hours. I’m comparing this pic to one taken around 1am where it reads 2300 psi. Will check again with soapy water. This time I’ll be checking around the manometer as well. 

 

[davidsng]

I had a leak at the fill nipple once. It was easy to fix. Just unscrew it, clean it, put some Loctite around the threads the screw it back in. Also, Sometimes the bleed port leaks because either you lost the small steel ball or it does not just seal. If it does not seal, put Teflon tape around it. If you lost the ball you can easily order one on online.

 

[davidsng]

If the valve is leaking it will come out the barrel. Put a balloon over the end of the barrel. Make sure you ck the bleed valve too.

 

[Ezana4CE]

If the valve is leaking it will come out the barrel. Put a balloon over the end of the barrel. Make sure you ck the bleed valve too.

@davidsng It’s worth checking out. I hope that’s not the case. Before it was the fill nipple assembly that leaked. The warranty replacement assembly came with some black stuff on the threads of the fill nipple. I tightened it down pretty tight and didn’t see bubbles. I actually didn’t check the bleed valve. That’s the only other area I can think of that I didn’t check for leaks besides the manometer. Thanks for the suggestion. This leak is irritating. 

 

[Ezana4CE]

Yesterday I removed the manometer and wrapped Teflon tape around the threads before replacing. The photos were taken 12 hours apart. I’ve noticed a slight loss of pressure. I’m unsure if the noticeable difference can be attributed to a slow leak or temperature a change in the reservoir. I thought I was filling the reservoir slowly, but after I reached the desired fill pressure the end of the reservoir further at from the receiver was warm. I’m wondering if the loss in pressure can be attributed to the temperature change as opposed to a leak. I see a loss of what appears to be <100 psi. I will continue to monitor the gauge to determine if it’s still leaking.

This picture was taken this morning approx 12 hours later. If you’re wondering, yes it’s mounted upside down. This was done intentionally.

 

[Ezana4CE]

Holding air like a champ now! I haven’t seen the gauge move in three days. Had a leak from two different locations, but it looks like that problem has been solved. 

 

[Crux100]

Good morning, I saw your post from last year about having issues with your shroud mount and the shroud mount screw on your Benjamin Bulldog. I'm having the exact same issue, where the set screw came loose - I got everything back in place and tightened the set screw, but now that damn shroud screw only screws in like less than half way. Did you end up doing anything special to get yours to go in?

 

[Ezana4CE]

Good morning, I saw your post from last year about having issues with your shroud mount and the shroud mount screw on your Benjamin Bulldog. I'm having the exact same issue, where the set screw came loose - I got everything back in place and tightened the set screw, but now that damn shroud screw only screws in like less than half way. Did you end up doing anything special to get yours to go in?

@crux100 My issue was that I thought I needed a replacement set screw because I didn’t see the one that was already installed. I expected it to be sitting flush with the top of the shroud mount/block. When I discovered it, it was down inside the block and I had to use a flashlight shined into the hole to see it. The replacement screw only went halfway down because I was trying to screw it in on top of the original set screw. The original set screw was loose from what I recall. Try sticking an Allen wrench down in the block to tighten down the set screw.