Brand new Impact problem

Can you post some pictures? Here something to check https://drive.google.com/file/d/0B0Ph4Q8M-S89dkNXSFI2VG8xYTA/view

What dealer did you purchase this gun from?

Hi,

I am no expert, just someone who has an interest in how things work and who owns two Impacts a Crown and a Bobcat.

First of all, is the gun a generation 1, 1.5 or Impact X? How to check? Gen 1 regulator piston is short and has 11 Bellville washers and regulator adjuster C37 has a pointed tip, 1.5 has longer reg piston (15mm I think), 16 washers and C37 is tipped with a dome, Impact X has long piston and 11 larger washers, C37 is domed and C36 is bigger in diameter, 10mm OD at the C39 contact surface.

The above is important as the o ring specifications have changed over time. The primary change has been the hardness of the o rings, BUNA 70 to BUNA 90 on part number C38 and C39, furthermore, on the Impact X, part C39 is now 10x1.5 BUNA 90 instead of 9x1.5 BUNA90. The parts are not interchangable, a Gen 1 Impact needs to have a Gen1 piston and adjuster. Gen1.5 and Impact X share the same piston and adjuster but have different washers and different C36.

The regulator breath hole is located between sealing surface C39, C35 and C33. The breath hole is required to create a pressure differential between the low and high-pressure sides and to help troubleshoot leaks. If air is dumping from the breath hole then one of the C 39,35 or 33 surfaces is not sealing.

Part C34 needs to be perfect, no scratches or holes on the face and no deformation or scratches on the cylinder part that contacts C35, use a magnifying glass to check, sometimes when removing C34 it can get damaged, I have messed up a few without much force. The leak you are describing seems to me to come from part C39 or from C 35/34 but could also be from part C33. If the hissing sound is high pitched sound then it's probably a high-pressure side leak C39 or C35, if it's a lower pitched sound then it is probably from the low-pressure side C33. I think that if the reg pressure is rising and then suddenly starts to leak from the breath hole then the low-pressure side is leaking as the pressure rises above the leak pressure of the o ring at that location, I have never had this issue, and I haven't heard of this happening so I am just trying to use my faulty logic to guess! I have had a leak from the breath hole but it has always been C39 for me...

You don't mention what version of gun you have so its difficult to tell if you have maybe put a smaller o ring (C39) into an Impact X? When removing C39 it is very easy to create a dent in the o ring groove, the sealing surface is the side of the groove closest to the bleed hole, use a bright light to check this surface, if it is scratched and not very deep then you could replace C39 with 9x1.5 BUNA70 and see if the softer o ring seals better, harder o orings deform less and are stronger but also require a perfect contact surfaces to seal, softer orings are less durable but can conform to scratches if they are not too deep.

I am friends with the local FX service center in my country, and had a chat with him a few weeks back regarding a Gen 1 impact that had a similar issue, long story short, he had to use a bore scope to inspect the C39 o ring groove, it had a very bad scratch in the groove not on the groove face, probably from removing the o ring, that caused the gun to leak from the breath hole, the only solution was to replace the complete receiver!

mubhaur. I feel your pain. Don't let it get you down. These types of problems happen from time to time. You will figure it out and get it repaired and learn from the experience. Then you will feel comfortable working on PCP's. Good Luck. Sylvan

Hi mubhaur, it sounds exactly like the fault from this guy here

https://www.youtube.com/watch?v=ASuZ3vWbUXQ&feature=push-u-sub&attr_tag=tfnlR3ZOYruVi2hM%3A6



around min 17 or so.

Maybe use NBR70 o rings, as it give more expansion under pressure, 90's it's harder, normally used for moving parts.

Hi,

I also just remembered on Gen 1 Impacts, that when you initially charge the rifle, it sometimes helps to adjust the regulator screw two full rotations anti-clockwise from the fully clockwise position, I seem to remember learning this from Ernest Rowe on one of his Impact videos. This procedure was to prevent leaking from the adjuster screw, but it may also help create an initial pressure jump that may help to seat all the o rings suddenly, instead of gradually, may be worth a try to see if it helps.

Hi mubhaur, it sounds exactly like the fault from this guy here

https://www.youtube.com/watch?v=ASuZ3vWbUXQ&feature=push-u-sub&attr_tag=tfnlR3ZOYruVi2hM%3A6



around min 17 or so.

Click to expand...

Some very useful information for possible FX buyers in that video. Thank you.

Sounds like if you're going to buy an FX it makes a lot of sense to learn how to change out the O-rings yourself.

Its not the reg. Its an o ring. NO SCRATCHES in housing? Like previous post. Remove tank vent air from gun. Up reg pressure to approx 150 bar , depending on your reg pressure, and reinstall bottle. You can remove bottle and drain gun to lower reg pressure if this fixes it.

Raisp thanks for sharing your info on this , great way of informing us differences and trouble shooting , The impact is a complicated pcp , and it is not a gun for those who cant tinker

Hi Hubmuair dd you resolve gun ? please explain when it started and what you did , as far as orings and checking the bore for defects < I have had many leaks in fx guns and I once went crazy on one before fixing it , are u lubing oringr when installing ? and like it said did u install proper size oring for your gen type? , I like to add , try installing orings on piston lubed and feel if they all have some drag in the bores if not they will leak , alot of times I have had to go to a slightly birrer size weather it is bore or wear ,

One thing you can try since you have had gun apart so much and probably dont have a huge assortment of oring sizes , get a roll of teflon tape,

OK here try this remove orings wrap teflon tape around the oring groves like 2 to 3 wraps and reinstall orings , I found sometimes this will fix a problem with a defect , if it works leave it or buy a slightly larger oring , the telltale hole is to tell you there is a problem in orings or piston bypassing and it is one of a few places only as others described ok let us know good luck ,

Hi,



The worst case scenario would be to source a new receiver from the closest authorized FX agent. It may be difficult to get a gen 1 receiver, might make sense to order an Impact X receiver, regulator body (C36), piston (C34), adjuster (C37), and 11 Bellville washers. The rest of your gun will attach to the new receiver no problem, then it will be an Impact Gen1X

What prompted you to change the o rings in the first place? Was the gun holding pressure at any stage and if so what was the most recent work that was done to it? Are you able to use a new part A34? Sometimes small fibers contaminate o ring grooves, try to clean out the whole area with tissue paper soaked Ballistol, then use a brand new microfiber cloth and a thin wooden or plastic rod to wipe off the excess lubricant, it should look spotless and free of any debris, then be liberal with the lube on the o rings.

I love a challenge as much as the next person, pitty you are on the other side of the world, hang in there and keep us posted, the more detail you can give us the more ideas we can throw back at you.

@ jwrabbitt123

Your thanks are most appreciated...

Which oring you used to fix the problem?