My Yong Heng must have been built on a Monday

[Corvid_hunter]

Filling my 6.8L tank for the first time my compressor gauge poop the bed. I replaced it with a M10 bolt. I then noticed I bad a bit of an oil leak and when I checked the 4 bolts on the front cover, all were not tight. Went to top off my tank today and the relief valve was leaking. I put a new burst disc in it and it was still leaking. Searched the forum here and found out there is supposed to be a white plastic washer in the threaded hole. Put the compressor up on the bench because the floor is too low, check the hole and there is no white plastic washer in there. I took one out of the spare parts, installed it and finger tightened the plug and gently snugged it up. Started the compressor and it was still leaking. Tightened it a bit, still leaking. Tightened it some more, still leaking air. Pull it out, place a bolt in the hole and no air leaking. My tank has 2 gauges so I started the compressor and filled from 200 bar to 300 bar staring at the gauges. Purge the lines, shut everything down and it looks like there is a small oil leak somewhere on the back of the compressor. What's the chance there's a loose bolt somewhere back there.

Does the whatever it's called on the right look like it's cracked? Could this cause the leak through the vent hole?

 

[biohazardman]

The main purpose of that part of the burst disc assembly is to push against the burst disk itself to seal it. So long as it is not cracked all the way through so it will not seal at the front surface, near what looks like a crack, it should be OK. Still it is ugly and I would probly just replace it as the part is so inexpensive.

Edit; Oops brain dead yes it looks cracked and ugly so needs replaced.

https://www.aliexpress.com/item/1005001952953207.html?spm=a2g0o.productlist.0.0.aa8822bfk9G8XP&algo_pvid=40980d77-c314-46a3-bcd0-53ebf71f78fb&algo_exp_id=40980d77-c314-46a3-bcd0-53ebf71f78fb-45&pdp_ext_f=%7B%22sku_id%22%3A%2212000018207922930%22%7D

Yes I got a Monday unit for my second one too. Loose bolts and fittings and no locktight on the second stage piston. So, I had to replace it soon after I bought it. But it has been good for twenty plus hours now. Gauges are just crap. I have to replace mine every 8 or 10 months. So ten or twelve hours of use.

 

[Saltlake58]

Yours might have been right after mine on the line. I've replaced the small piston, replaced seals repeatedly, gauges, you name it, I've replaced it. 

Each of the little stainless steel pipes is a leak point. Each end uses a dowdy seal and I've blown at least 10. If it's running, you can hold your hand a few inches away from the compressor and feel any leaks. If it's leaking and you can't figure out where, use a little soapy water on the spits where it might be leaking.

They work, but sure can be high maintenance.

 

[paulemar]

My lightly used Yong Heng which I use to top off my 74 cut tank is 2.5 years old & first thing I did when I got it was to check for tightness every connection. Most were OK but a few needed another 1/2 turn to tighten. It's been pretty decent & reliable except for a pressure safety plug which blew out once. My main concern was finally, after a year, settling on an oil (expensive Chemlube 751) and cooling method which I am finally satisfied with.