Yong Heng leak - how can I fix?

So, I just had to replace a Dowdy washer on one of the three pipes on the front of the compressor. It was the vertical pipe. I've always had trouble getting this one to seal and stop the air leaks. This time, I just can't get it to seal.

Any suggestions on getting that vertical pipe to seal? I've had it on and off at least a dozen times. Tried wiggling it in, tighter than I've ever done it before (but that raises the risk of stripping the aluminum blocks). I buy a new pipe for about $25 and I don't mind spending the $$, but it's the time. 3 to 4 weeks shipping.

The compressor is nearly 3 years old, with light use due to so many problems.

Any suggestions on getting the vertical pipe to properly seal so I can hit pressure?

Thanks in advance
 
I had the same problem once I went through a couple of Dowty seals, as they are very poorly made, and another time it ended up being the ferrule to pipe connection like rc4fun said. I invested in a set of pipes for just about $20. The new pipe with new ferrules cured the leak. They do some pretty rough werq on the pipes and fittings on these things. I was going to send you the line off of my spare compressor but fergot I messed it up taking it apart some months back.
 
It's not the dowdy seal, that's replaced and confirmed sealed. It's the pipe itself with the strange little permanently installed funnel shaped gasket.

Just not sure where to go from here. I've considered roughing up the surface as it looks incredibly smooth and might need fresh material to seal.

any thoughts welcome.

Oh, and I bought a 20 pack of high quality dowdy seals, not the Yong Heng crap. The replacement seals work like a charm.
 
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I ran into the same problem when replacing my Dowty Washer. I was able to get it to seal by loosening both ends and giggling the pipe to make sure the alignment was as straight as possible. If properly aligned the nuts should be able to be screwed back up with the fingers before being firmly snugged tight with spanners. It took me a couple of attempts but it did eventually seal without having to buy a new pipe. PS. Don't sand anything unless there is a bur of some kind. If your pipe is not bottomed out before tightening the nut it will never seal.
 
OK, I just spent 30 minutes sanding the ferrules with 500 and 1000 grit sand paper. Reinstalled and tightened with two apposing wrenches and really tightened them down. I think I have success for today. Probably last time these tubes will ever work, so I'll consider this a temporary fix and order new tubes.

Thank you for the help and link to the tubes. I'll get them ordered in preparation for the next repair (it's just a matter of time)


 
I ran into the same problem when replacing my Dowty Washer. I was able to get it to seal by loosening both ends and giggling the pipe to make sure the alignment was as straight as possible. If properly aligned the nuts should be able to be screwed back up with the fingers before being firmly snugged tight with spanners. It took me a couple of attempts but it did eventually seal without having to buy a new pipe. PS. Don't sand anything unless there is a bur of some kind. If your pipe is not bottomed out before tightening the nut it will never seal.

As for sanding, I started with 500 grit and moved up to 1000. I have 2000 grit if I need it, but this seemed to work. I did jiggle, cajole, encourage, and eventually resort to brute force. Both nuts did align before hand tightening. Finished off with the wrenches. so far, it's holding.

This compressor was great till the piston broke, since then, it's one repair after another. Couple more repairs like this and it'll be a new compressor using this one for donor parts for the new compressor repairs. Maybe next time I won't get a lemon.

Thanks again all for the feedback
 
if you are about to order the spare pipes, just give it a last try with some loctite :) Like nr. 263

https://www.henkel-adhesives.com/us/en/product/threadlockers/loctite_263.html

Hadn't thought about Loctite. For right now, it all seems to be holding (till it doesn't). I have Loctite here, so, when it cuts loose again, I'll give it a try. 

I did order new tubes. At $22 shipped, that may solve a major headache for me. All I want to do is shoot, not continually try to repair this thing. Then again, if I replace all the parts, eventually this thing will be completely rebuilt with relatively new parts and I'll have a new compressor the hard way!