PCP Seneca Aspen

[Madhatter]

I did the same pumps after each shot to bring the pressure back up to my best pressure. I didn't count pumps per say. I watched the pressure gage and stopped when I reached my goal.

 

[fixxit]

The biggest mistake people make when shooting the Aspen/freedom is they shoot 5 or 6 shots and then pump it back up to fast and to many. 1 shot and pump 5 to 6 times. Another shot and pump 5 to 6 times. Over oil the pump with silicone oil. It keeps the pump from heating up and keeps it well lubed. BB Pelter did a complete test of the Aspen and came up with that. You are the regulator. I found it most accurate at between 2800 and 2900 psi. My problem is the check valve didn't work quite like it was designed and it was my first PCP and didn't want to return it. The leaking check valve continued to get worse and then I tried fixing it and couldn't get it to seal. It's been a paper weight for the last 5 years. The pump never gave me problems but would get very hard to move because the valve was leaking.

Are you sure it is not the pre-spring tube that is leaking? Mine did, and the effect was that the pressure dropped, but the pump did not lock up. Unfortunately, I cannot find the pictures that I made of that repair.
I think if the check valve leaks, it results in some kind of pressure imbalance which 'locks up' the pump.

 

[LostInMO]

Are you sure it is not the pre-spring tube that is leaking? Mine did, and the effect was that the pressure dropped, but the pump did not lock up. Unfortunately, I cannot find the pictures that I made of that repair.
I think if the check valve leaks, it results in some kind of pressure imbalance which 'locks up' the pump.

Hmmm....Well I didn't know the innerds of the thing so never thought of that. I'll find a diagram and give it a look. Or a whack with a rubber mallet....that's fixd a lot of stuff in my time

 

[Murfdurf82]

Are you sure it is not the pre-spring tube that is leaking? Mine did, and the effect was that the pressure dropped, but the pump did not lock up. Unfortunately, I cannot find the pictures that I made of that repair.
I think if the check valve leaks, it results in some kind of pressure imbalance which 'locks up' the pump.

I degassed 2 of mine when they leaked out of the pre spring tube and then degassed the tube. I dropped some silicone down there and my leak went away on both. I don't have pictures but I used a brass rod to push open the ball on the end of the tube and get some silicone to drop in in. Like 2 drops. I pushed the ball in several times to make sure oil got down in past that seal or o ring whatever it is and aft pumping it up it about 4 times over a few weeks it held pressure and has ever since.

 

[fixxit]

Hmmm....Well I didn't know the innerds of the thing so never thought of that. I'll find a diagram and give it a look. Or a whack with a rubber mallet....that's fixd a lot of stuff in my time

I've uploaded the diagrams a few posts before this one, check out the link below. To be honest, I found the repair of these rings incredible annoying due to the reassembly: the outer o-rings of the brass part have to pass holes of the tube, and they tend to get shaved there and thus leak. I tried several times carefully, but last repair I also opened this up again,.... and whacked it back in with a hammer been good ever since...
If I find the time and/or find the pictures back I'll make a write up from it.
by the way... I tested the leak by simply putting the tip of the gun in a bucket of water.... the point where the bubbles originate reveal which o-ring is leaking (the little check valve in there, or the 'outer rings' of the brass part)

please let me know If I can be of any assistance in the repair.

F

PCP Post in thread 'Seneca Aspen'

Jan 2, 2026

Please see attached two assembly instruction manuals for the Air Venturi Aspen Seneca.
Note that the 'AssemblyForSenecaAspen_small.pdf' file has been compressed, otherwise it was too big to upload (it might have affected the quality).
As I mentioned in my original post; One document I found on the internet, and one which was send to me by Air Venturi. I found at least the following 'subtle' differences between the documents (I'll add to the list if more are found):

1. The rubber rings have the inner ring dimensions in the one, and outer ring dimensions in the other. Remember this if...

• fixxit

• 
• 

 

[fixxit]

I degassed 2 of mine when they leaked out of the pre spring tube and then degassed the tube. I dropped some silicone down there and my leak went away on both. I don't have pictures but I used a brass rod to push open the ball on the end of the tube and get some silicone to drop in in. Like 2 drops. I pushed the ball in several times to make sure oil got down in past that seal or o ring whatever it is and aft pumping it up it about 4 times over a few weeks it held pressure and has ever since.

Have you also re-pressurised? If not, can you actually notice any difference? I expect (but am not sure) that without pressurizing:

• More pumps are needed from totally empty to reach the minimum firing pressure.
• With max pressure (200bar) you can fire more pellets than with the pre-pressure in there (since there is more air storage available?).

Is that true?

 

[Murfdurf82]

Have you also re-pressurised? If not, can you actually notice any difference? I expect (but am not sure) that without pressurizing:

• More pumps are needed from totally empty to reach the minimum firing pressure.
• With max pressure (200bar) you can fire more pellets than with the pre-pressure in there (since there is more air storage available?).

Is that true?

When I pumped up the pressure I think I did it with my cheap electric pump or the hand pump to give the gun pump a break. It still leaked out slowly, then I proceeded to dry fire the rifle multiple times(I read this rifle is ok from manufacturer to dry fire and I seen a post on another forum from like 2019 where a fella did the same and it worked for him so I followed his instructions) maybe from airgun warriors. After I dry fired like 4 times and I think the rifle was 3000 psi or around that, I left it alone. Pumped it up after a few days(took longer to leak out) and repeated maybe one or 2 more times over a period of a few weeks and it went away. Maybe the poppet wasn't totally sealed as well and the dry fire fixed this issue or when dry firing it gave enough back pressure or "pop" and helped seal it up. It was all trial and error. Now it keeps pressure for weeks. As far as how many "peak" shots after the leak was fixed. It helped because it wasn't leaking but it didn't make it better. That's the crutch of this rifle. So i said F it, I turned the hammer spring in all the way, backed it out 1 turn and in the power band 3500-3000 psi I can shoot a barracuda 21.14 gr 900-880 before it slowly falls off. And so if I want to sling it that fast I just pump it. The hammer spring is so easy to adjust an allen wrench, maybe 3mm there is a hole in the stock facing the back of the rifle. Fish it through and find it, turn clockwise for more power and opposite for lower power.....Edit I also added oil down the area one more when going through the leaking period. I made sure that I pressed in the ball w the rod to confirm it was degassed as well as the main tube degassed and added oil. 2nd Edit 2 I also over oil the pump a bit. I add a drop a lil more than recommended but haven't had an issue and have noticed from time to time w a bit of oil misting out w shots here or there. It hasn't affected anything other than taking the cap off the shroud, cleaning the area and cleaning the barrel lightly every 100 shots or so.

 

[fixxit]

When I pumped up the pressure I think I did it with my cheap electric pump or the hand pump to give the gun pump a break. It still leaked out slowly, then I proceeded to dry fire the rifle multiple times(I read this rifle is ok from manufacturer to dry fire and I seen a post on another forum from like 2019 where a fella did the same and it worked for him so I followed his instructions) maybe from airgun warriors. After I dry fired like 4 times and I think the rifle was 3000 psi or around that, I left it alone. Pumped it up after a few days(took longer to leak out) and repeated maybe one or 2 more times over a period of a few weeks and it went away. Maybe the poppet wasn't totally sealed as well and the dry fire fixed this issue or when dry firing it gave enough back pressure or "pop" and helped seal it up. It was all trial and error. Now it keeps pressure for weeks. As far as how many "peak" shots after the leak was fixed. It helped because it wasn't leaking but it didn't make it better. That's the crutch of this rifle. So i said F it, I turned the hammer spring in all the way, backed it out 1 turn and in the power band 3500-3000 psi I can shoot a barracuda 21.14 gr 900-880 before it slowly falls off. And so if I want to sling it that fast I just pump it. The hammer spring is so easy to adjust an allen wrench, maybe 3mm there is a hole in the stock facing the back of the rifle. Fish it through and find it, turn clockwise for more power and opposite for lower power.....Edit I also added oil down the area one more when going through the leaking period. I made sure that I pressed in the ball w the rod to confirm it was degassed as well as the main tube degassed and added oil. 2nd Edit 2 I also over oil the pump a bit. I add a drop a lil more than recommended but haven't had an issue and have noticed from time to time w a bit of oil misting out w shots here or there. It hasn't affected anything other than taking the cap off the shroud, cleaning the area and cleaning the barrel lightly every 100 shots or so.

Thank you for the write up. I have not yet touched the hammer spring adjustment. Maybe if I can use a speed meter for testing. I do recognize the oil misting out of the barrel, as I too over oil the pump; probably better than not enough oil I guess.

 

[fixxit]

Since I had to repair a new leak in the Air Venturi Aspen Seneca, I thought I should add new info and the pictures to this forum thread.
Note: The manuals have the wrong o-ring diameter documented!
The manuals have been provided in an earlier post in this thread and is updated with this info.

The leak was probably due to the ID8x2 mm o-ring, located on the part that is called "Air chamber extension tube rear connector" with Item Code "000P2-046-W-01"
I chose to also swap out the ID10x2.5mm o-ring. This ring has been mistakenly been documented as ID10x2mm o-ring in the manual.
See the pictures below for the disassembly photo's. Before you start disassembling this tube, degass the rifle in two places!! I cannot stress this enough:

• On the underside of your gun is the 'normal' degas screw, use it.
• On the front side of the gun, on the the pressure tube you that is going to be disassembled in this post, is a degas point (no pictures added). This tube is some kind of pre-pressure-air-'spring'. NOTE: you need a special fill probe (different than the normal fill probe) to actually fill this air-spring with air again. Obviously you also need a pump to fill it up. This write up assumes that you have such a fill probe and pump.

Any commends on the photo's are located below the photo's.
This is a continuation of the original posts starting at the URL: PCP - Seneca Aspen

I hope this is of help to anybody.




Removed the pressure gauge, took out the metal pin and unscrewed the pressure tube screws. Don't lose the little tiny metal thingy called "Air chamber extension tube baffle" in the manual. The pin you have to knock out with a little tap from the other side of the rifle. I would advise to leave the screws in and remove them at a later stage, after the pressure tube has been disassembled from the rifle.


pressure gauge, tiny little metal thingy, and "Air chamber extension tube rear pin"


Another photo, to show the dent in the metal pin.


I was too stubborn to open/disassemble the other side of the pressure tube (I had done once and it took be a long time to actually close it again). But because of the I had a hard time getting this metal part out: I used a thick plastic part that i hooked in the slit where the 10x2.5 o-ring should be. I figured the plastic part would deform before the metal flange would deform.


view of one side


view of the other side


Here you see the difference in thickness of the two ID10 o-rings

 

[Madhatter]

Are you sure it is not the pre-spring tube that is leaking? Mine did, and the effect was that the pressure dropped, but the pump did not lock up. Unfortunately, I cannot find the pictures that I made of that repair.
I think if the check valve leaks, it results in some kind of pressure imbalance which 'locks up' the pump.

Oh I'm sure it's the check valve. I can hear it leaking and I've even filled it up with my scba tank.

 

[fixxit]

Oh I'm sure it's the check valve. I can hear it leaking and I've even filled it up with my scba tank.

OK, can you please let me know if fixxing the check valve has resolved it?
About a month ago I changed the o-rings of my check valve. It is quite 'easy' in the sense that the pump can remain in one piece.

 

[Pumacarl]

WOW! Just WOW! What an epic posting @fixxit! I am sorry I missed this when you first started back on your Jan. 2nd posting. Your series of posts are pure gold to anyone who owns or works on these guns. Great bit of detective work and figuring out and documenting. I love reading posts like this one. Thankyou, for putting in the time and effort.