American Air Arms Oring help on evol

[Nealgl1985]

I went to toms website and downloaded the oring sheet with all the sizes and figured since it took me a few minutes to search everything out I would post it here.

Will someone that is familiar orings and the sizes please double check and confirm I'm not ordering the wrong stuff?

If everything checks out then others can use the links to quickly make their own oring kits for their evols.

1.5mm X 7mm (NBR) Buna-N 70 Duro Metric O-Ring: C-026-1070-00 1.5x7mm 70 Buna Gauge, Foster

1.5mm X 7mm (NBR) Buna-N 70 Duro Metric O-Ring [N1.50X007] : The O-Ring Store LLC, We make getting O-Rings easy!

The O-Ring Store LLC 1.5mm X 7mm (NBR) Buna-N 70 Duro Metric O-Ring [N1.50X007] - Cross Section "CS" X Inside Diameter "ID" Metric O-Rings Buna-N 70 Duro (NBR): The most commonly used elastomer for sealing products. Nitrile, also known as Buna-N or NBR, is a copolymer of Butadiene and...

www.theoringstore.com

1.5mm X 10.5mm (NBR) Buna-N 70 Duro Metric O-Ring: C-026-1105-00 1.5x10.5mm Buna 70 Gauge Space

1.5mm X 10.5mm (NBR) Buna-N 70 Duro Metric O-Ring [N1.50X010.5] : The O-Ring Store LLC, We make getting O-Rings easy!

The O-Ring Store LLC 1.5mm X 10.5mm (NBR) Buna-N 70 Duro Metric O-Ring [N1.50X010.5] - Cross Section "CS" X Inside Diameter "ID" Metric O-Rings Buna-N 70 Duro (NBR): The most commonly used elastomer for sealing products. Nitrile, also known as Buna-N or NBR, is a copolymer of Butadiene and...

www.theoringstore.com

AS568-005 U90 EU Polyether Urethane 90 Duro O-Ring: C-025-0005-11 Polyurethane 90 Durometer 22 Cal Breech/Bolt

AS568-005 U90 EU Polyether Urethane 90 Duro O-Ring [U90005] : The O-Ring Store LLC, We make getting O-Rings easy!

The O-Ring Store LLC AS568-005 U90 EU Polyether Urethane 90 Duro O-Ring [U90005] - 3/32"ID X 7/32"OD X 1/16"CS Polyurethane: EU Polyether Urethane General Purpose EU Polyurethane rubber is notable for its combination of hardness with elasticity, outstanding abrasion resistance and tear strength...

www.theoringstore.com

AS568-008 U90 EU Polyether Urethane 90 Duro O-Ring: C-025-0008-11 Polyurethane 90 Durometer Regulator Adjuster & Piston 30 Cal. Breech/Bolt

AS568-008 U90 EU Polyether Urethane 90 Duro O-Ring [U90008] : The O-Ring Store LLC, We make getting O-Rings easy!

The O-Ring Store LLC AS568-008 U90 EU Polyether Urethane 90 Duro O-Ring [U90008] - 3/16"ID X 5/16"OD X 1/16"CS Polyurethane: EU Polyether Urethane General Purpose EU Polyurethane rubber is notable for its combination of hardness with elasticity, outstanding abrasion resistance and tear strength...

www.theoringstore.com

AS568-004 U90 EU Polyether Urethane 90 Duro O-Ring: C-025-0004-11 Polyurethane 90 durometer Foster Check Valve

AS568-004 U90 EU Polyether Urethane 90 Duro O-Ring [U90004] : The O-Ring Store LLC, We make getting O-Rings easy!

The O-Ring Store LLC AS568-004 U90 EU Polyether Urethane 90 Duro O-Ring [U90004] - 5/64"ID X 13/64"OD X 1/16"CS Polyurethane: EU Polyether Urethane General Purpose EU Polyurethane rubber is notable for its combination of hardness with elasticity, outstanding abrasion resistance and tear...

www.theoringstore.com

AS568-013 U90 EU Polyether Urethane 90 Duro O-Ring: C-025-0013-11 Polyurethane 90 Durometer Regulator Piston, Valve Body

AS568-013 U90 EU Polyether Urethane 90 Duro O-Ring [U90013] : The O-Ring Store LLC, We make getting O-Rings easy!

The O-Ring Store LLC AS568-013 U90 EU Polyether Urethane 90 Duro O-Ring [U90013] - 7/16"ID X 9/16"OD X 1/16"CS Polyurethane: EU Polyether Urethane General Purpose EU Polyurethane rubber is notable for its combination of hardness with elasticity, outstanding abrasion resistance and tear strength...

www.theoringstore.com

AS568-016 B70 (NBR) Buna-N Nitrile 70 Duro O-Ring: C-025-0016-01 Buna 70 Durometer
Chamber Insert

AS568-016 B70 (NBR) Buna-N Nitrile 70 Duro O-Ring [B70016] : The O-Ring Store LLC, We make getting O-Rings easy!

The O-Ring Store LLC AS568-016 B70 (NBR) Buna-N Nitrile 70 Duro O-Ring [B70016] - 5/8"ID X 3/4"OD X 1/16"CS Buna-N O-Rings 70 Duro (NBR): The most commonly used elastomer for sealing products. Nitrile, also known as Buna-N or NBR, is a copolymer of Butadiene and Acrylonitirle. It has a...

www.theoringstore.com

AS568-122 V90 Fluorocarbon FKM 90 Duro O-Rings: C-025-122-21 Viton 90 Durometer Front Block, Regulator

AS568-122 V90 Fluorocarbon FKM 90 Duro O-Rings [V90122] : The O-Ring Store LLC, We make getting O-Rings easy!

The O-Ring Store LLC AS568-122 V90 Fluorocarbon FKM 90 Duro O-Rings [V90122] - 1-1/8"ID X 1-5/16"OD X 3/32"CS Chemical Resistant and High Heat Fluorocarbon FKM O-Rings 90 Durometer: Fluorocarbons (FKM) – commonly referred to as Fluorocarbon FKM, has excellent resistance to high temperatures...

www.theoringstore.com

C-025-122-21
Polyurethane Durometer 90
Front Block, Regulator
(SAME SIZE AS ABOVE BUT THIS IS ANOTHER OPTION BASED ON @Bladebum on ham RECOMMENDATION) if you are having issues with the Viton 90 Durometer then you might want to try this out.

AS568-122 UC90 Cast Polyurethane 90 Duro O-Rings [UC90122] : The O-Ring Store LLC, We make getting O-Rings easy!

The O-Ring Store LLC AS568-122 UC90 Cast Polyurethane 90 Duro O-Rings [UC90122] - 1-1/16"ID X 1-1/4"OD X 3/32"CS High performance 90 Durometer Cast Polyurethane High Performance Urethane O-Ring for heavy duty applications. DISOGRIN 9251 Material with outstanding wear and tear resistance, very...

www.theoringstore.com

AS568-117 B70 (NBR) Buna-N Nitrile 70 Duro O-Ring: C-025-0117-00 Buna 70 Durometer Regulator

AS568-117 B70 (NBR) Buna-N Nitrile 70 Duro O-Ring [B70117] : The O-Ring Store LLC, We make getting O-Rings easy!

The O-Ring Store LLC AS568-117 B70 (NBR) Buna-N Nitrile 70 Duro O-Ring [B70117] - 13/16"ID X 1"OD X 3/32"CS Buna-N O-Rings 70 Duro (NBR): The most commonly used elastomer for sealing products. Nitrile, also known as Buna-N or NBR, is a copolymer of Butadiene and Acrylonitirle. It has a...

www.theoringstore.com

 

[Dairyboy]

Yup looks good! I realize I got Poly 90 orings in the 122 size instead of Viton 90. Doubt it makes much difference and is working fine in mine. But yes those are good.

 

[Nealgl1985]

Thanks for confirming!

Yup looks good! I realize I got Poly 90 orings in the 122 size instead of Viton 90. Doubt it makes much difference and is working fine in mine. But yes those are good.

 

[Dairyboy]

Do you have a leak or just having some in case?

 

[Nealgl1985]

Yes she's leaking from the barrel area. When it was empty with the gun cocked and probe in the open position I covered the barrel with my finger and and it sealed up and accepted air then emptied out overnight. I'm made a thread on ham about the leak. Hoping to get some help from some experienced individuals. I'm a newbie when it comes to complete tear downs and tuning. @Dairyboy

 

[_CTAIRGUNNER_]

@Nealgl1985 great thread that is going to help a lot of people! As far as working on the mini, it will be a breeze believe me. Super simple, and youll be a pro in no time!

 

[Nealgl1985]

@Nealgl1985 great thread that is going to help a lot of people! As far as working on the mini, it will be a breeze believe me. Super simple, and youll be a pro in no time!

Thank you for the words of encouragement! I will document the process for anyone else that might have the same questions.

 

[_CTAIRGUNNER_]

Thank you for the words of encouragement! I will document the process for anyone else that might have the same questions.

If you have any questions feel free to reach out, I am not the best when it comes to explaining things as I just do and somehow succeed but if I can help i will!

 

[nervoustrig]

Yes she's leaking from the barrel area.

I haven’t worked on an Evol but the symptom you describe is usually the result of a poppet leak at the valve seat. In other words, not an O-ring. Hopefully @Dairyboy or @_CTAIRGUNNER_ or another member intimately familiar with it can comment.

 

[Dairyboy]

I'll post here and on HAM.

Are you 100% sure the leak is from the barrel? When filling these guns from empty I've always had to put my finger over barrel to seal. Also no need to cock the hammer as they have a floating hammer so no pressure on valve stem. I havent heard of a valve sealing issue yet but anything is possible I suppose. I'd venture to say it's not that though.

Anyways It's very simple. First I degas but in your case you don't need to. But loosen the burst disk until you hear air leaking and then leave it be. Depending on time when yours was made its either on the side exposed or hidden under the chassis. Mines older and exposed. If its under the chassis you obviously cant do it until the chassis is off. Once you remove the barrel, which they are on there tight so don't be afraid to hit the wrench with your palm or rubber hammer or something. You won't break anything on the gun. Anyways remove the barrel then you need to remove these 2 screws. The large one holding the chassis to the block, and the front one holding the rail to the fill/gauge block.

Then remove the safety bolt. Then simply remove chassis from the action. After that unscrew the airtube from action and fill block also. You then need to push the reg out. A wood dowel or piece of PVC pipe is what i use. I push from the regulated side so not bump the adjustment screw on the other end. There will be 3 orings here, 2 on reg and one on fill block. Reg has one -117 and one -122 oring. The fill block -122. I wouldn't mess with the orings internally on the reg, haven't heard of any issues there but never know. Also I would at this time do the foster fitting orings and under the gauge on the fill block. The foster fitting leak is I think the most common on these guns.

EVOL - Foster fitting leak

I've heard people have issues with the foster fitting check valve sticking open, myself included. A quick drop of silicone oil in the foster fitting and a fill was a nice bandaid fix that did last me quite some time. I tore my gun down last night to remove any silicone oil/grease and lube with...

community.hardairmagazine.com

After this clean your threads good, lube with ultimox and the orings and screw it together. Make sure you put the reg into the breech block first and then screw the tube on to it. After that just make sure you lineup the front block to the rail for the bolt to go it before putting air in.

This video helps alot also! I'd recommend watching it.

 

[Nealgl1985]

@Dairyboy Thanks for the write up! I will have to do the soapy water test to see where the actual leak is coming from. I just assumed it was from the barrel since I covered it and it started holding air.

 

[nervoustrig]

The usual way to check for a poppet leak is to stretch a rubber band over the end of the barrel and wait a few minutes to see if it begins to inflate.

 

[Airgun-hobbyist]

The most common random leak in the early Evol was at the pressure gauge on the end of the air tube. Fill it with air and check for bubbles there first. Removing the gauge is tricky so as to not mar up the rifle because there's little room for a socket in that hole. It requires the specialized socket made by AAA, or to make a skinny socket. I turned a socket down on a lathe, but one could be ground down to size just as easily. The only other area that I have had a leak from is the air tube o-ring, but because I tend to tinker and would re-use the o-ring upon re-assembly while tuning for heavier slugs. Otherwise, they seldom leak anywhere else. The burst disk could also be the culprit if it was overfilled and shifted/swelled the brass disk insert.