Yong Heng high pressure (4500 psi) air compressor venting out of top instead of filli

[Jambi1369]

Hello. I have a yong heng high pressure air compressor that I use for filling my HPA air tanks that I use on my markers. I got it on Amazon. Yesterday was the first time I ran this thing. Here’s my issue :

I have a few 90 ci (cubic inch) 4500 psi HPA air tanks and a few 80 ci 4500 psi HPA air tanks. Yesterday I filled 2 of my 90 ci 4500 psi tanks and 1 of my 80 ci 4500 psi tanks. When I ran the compressor it filled all 3 of my 4500 psi tanks to 4500 initially but as they cooled down they all went down about 500 psi each so each one had 4000 psi. This is normal and what happens when the tanks cool down, so I just top them back off after they cool down.

now, when I went to top them off to 4500 I couldn’t get the dials on any of the 3 tanks’ gauges to move at all past 4000 psi. I also started to notice a leak sound along with the hum of the compressor running and I noticed it was coming from around/underneath the nut on top of the central cylinder head (pic included). So I guess that even though when I held the bottles in my hand they were vibrating (feeling like air was indeed going into them) the air was instead venting out from this leaky nut, hence the gauge needles not moving anymore.
Now, I’m thinking 1 of 2 things must be the problem:

first, I’ve heard in reviews that this compressor sometimes has trouble actually filling all the way to 4500 psi even though it’s rated that high. So, I’m thinking, maybe once the tanks each reached 4000 psi in pressure the air compressor couldn’t actually push any more air into them against that much pressure and instead started venting the air out from around that nut instead.

or, second option, the air compressor somehow broke/became damaged and I either have to repair or replace it.

so, sorry about that lengthy post. However, does anyone know which of those options is the culprit (or whatever else is the problem maybe)? And if it is broken/damaged, is anyone able to tell me how I could fix/repair it and what exactly I would need to do this?
Again, sorry for the lengthy post and thank you very much in advance for your help and your time. It is much appreciated. 
- Kris
Here are the pics. First pic is the air compressor I have. Second pic is the zoomed in view of the central cylinder from the first pic and I have circled in blue where the leak is coming from. Thanks again in advance.






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[Tunaman]

So it worked for exactly ONE day! That is God punishing you for buying the POS Chinese junk that put Tom Kayes Shoebox out of business. You can call their tech support line...oh wait!
Now that is out of the way, spray it down with soapy water to find the leak, then use teflon tape or thread sealant to stop it. The slightest leak and it wont top off at all.

[Jambi1369]

So it worked for exactly ONE day! That is God punishing you for buying the POS Chinese junk that put Tom Kayes Shoebox out of business. You can call their tech support line...oh wait!
Now that is out of the way, spray it down with soapy water to find the leak, then use teflon tape or thread sealant to stop it. The slightest leak and it wont top off at all.

lol…not even one day. One RUN essentially. Trust me too, I’ve been cursing china up and down since it happened yesterday. I didn’t want to buy this thing anyways, I looked for brand name up and down but this was the only one I could find that reaches 4500 psi (allegedly anyways) on the entire internet (or other Chinese ones that looked even crappier). The only solid looking one I found was like two grand. I already had to return this once because the first one they sent me was missing half the parts so now I’ll be on my third one of these if I can’t fix it. I was thinking taking a wrench and removing the nut and loc tiring it back on but I wasn’t sure if that was viable or if I’d need specialty parts or o rings or anything.

Anyways, any suggestions on what might be a better model/brand that can do at least 4500-5000 psi?

Thanks for your time

- Kris


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[Tunaman]

lol…not even one day. One RUN essentially. Trust me too, I’ve been cursing china up and down since it happened yesterday. I didn’t want to buy this thing anyways, I looked for brand name up and down but this was the only one I could find that reaches 4500 psi (allegedly anyways) on the entire internet (or other Chinese ones that looked even crappier). The only solid looking one I found was like two grand. I already had to return this once because the first one they sent me was missing half the parts so now I’ll be on my third one of these if I can’t fix it. I was thinking taking a wrench and removing the nut and loc tiring it back on but I wasn’t sure if that was viable or if I’d need specialty parts or o rings or anything.

Anyways, any suggestions on what might be a better model/brand that can do at least 4500-5000 psi?

Thanks for your time

- Kris


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Buy once cry once. Look for a used Bauer or something like it. Old Military scuba compressors can be had for a good price too. Look around.

[maniacmechanic]

Compressors in general , have a hard time starting against a load ,, fix your leak ,, and if ya have to build to 4500 , make ya a cold bucket ,, keep your tank cold thru the fill process
And Tuna is correct also

[Jambi1369]

Buy once cry once. Look for a used Bauer or something like it. Old Military scuba compressors can be had for a good price too. Look around.

Yes the baur ones actually look quite good. Thank you


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[Jambi1369]

Compressors in general , have a hard time starting against a load ,, fix your leak ,, and if ya have to build to 4500 , make ya a cold bucket ,, keep your tank cold thru the fill process
And Tuna is correct also

Thank you. Yes I was thinking about maybe putting the tanks in a cold bucket (ice or something with a towel over it maybe) when filling but wasn’t sure if it was a good idea. Thanks.

Also, I’ve been using triax Kompressor oil iso 46 for this compressor. It needs iso 46 oil. I just noticed a thing online though that says not to use the triax oil for breathing air compressors. Anyone know why that might be? And anyone got a good conpressor oil they use that is iso 46 and good for high pressure applications? The other couple of oil brands I know are good either don’t seem to make iso 46 (only iso 100) or I can’t find enough info on them to see whether or not they have the same breathing air compressor restriction that triax has for some reason. Any recommendations would help greatly and I appreciate all the help so far.


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[Jambi1369]

Also, with the shoebox. I’d really like to buy a used one and just use that for the quality/reliability, but don’t you still need to hook it up to another compressor to use it (especially to get anywhere near 4500)? I would still need to connect it to this crappy piece of junk I’ve got now, wouldn’t I ? Thanks.


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[Tunaman]

Yes. You need a small compressor to feed the shoebox. I use the Makita as it is quiet.

[Jambi1369]

Yes. You need a small compressor to feed the shoebox. I use the Makita as it is quiet.

Thank you. Yes, I was just looking at it online some. I saw that an ordinary compressor will work. I like that option much better honestly (than this high pressure Chinese crap). And it seems like overall a much cheaper option than the good high pressure units. It’s just finding one that’s the hard part.

How hard is it to find a used one in good shape (or even decent shape)? I don’t even know where to start with trying to find one.


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