"Whatever can happen at any time can also happen today." - Lucius Annaeus Seneca
It's been a bit of a waiting game with the compressor. For one thing, we are doing Christmas decorating, and for another, there's a high-maintenance dog I am afraid to leave in the house with the other dog. I was waiting for a tap to arrive, and now I'm waiting on some parts.
I got this thing a couple of weeks ago, and had a brief opportunity to work on it a little bit more.
I wasn't sure if bits of the nipple for the air filter had gone inside the cylinder. I tried looking inside using my little USB borescope, but it wouldn't bend down, and the camera lens kept getting fouled. As you can see, the camera body is a bit long, so I couldn't bend it as much as needed.
In the end, I had to remove the top of the cylinder - something I've never done on an air compressor before. I've done it on car engines a few times, but never on a compressor. It's a bit different from an internal combustion engine, but fortunately it's fairly simple.
Below: On the left side - air is pulled in through the inlet valve as the downward motion of the piston creates a vacuum. The vacuum holds the discharge valve shut against its seat.
In the right image - air is forced out through the discharge valve, while the suction valve is pushed shut by the air pressure. Both valves are simple one-way reed valves.
Below: The inside of the cylinder head. The bottom half is the suction chamber (intake side), and the top is the discharge. At the bottom is where filtered air enters the suction chamber. The seller told me he hadn't run it without the inlet filter. The layer of brown sawdust inside the suction chamber says otherwise :)
Speaking of the inlet filter - which had boogered up the threads in the air inlet - the 1/2" NPT tap arrived. I cleaned up the threads for the inlet filter as well as I could. They aren't perfect, but they are much better. If I need to replace the cylinder head, they are available for about $18.
I'm glad that I decided to remove the cylinder head. The accumulation of sawdust had to be affecting the intake valves. The valves were covered with sawdust blended with compressor oil. Below is the upper valve plate. It's hard to believe all those deposits were caused by clean filtered air! You wouldn't want sawdust in your air tools anyway, so it will be good to have clean pump internals.
In this compressor model, there are two plates that stack on top of one another. These sit between the cylinder and cylinder head, and these plates hold the reed valves in place.
Below, the lower plate. This plate holds the reed valves, and is still stuck on the cylinder - it was pretty difficult to get it free. It was also fouled with oil/sawdust grime.
After a fair bit of effort, I was able to take the lower plate off. Inside, the top of the piston was covered with gunk. The sides of the cylinder were in good condition though, and I could still see honing marks, and no scratching. Apparently nothing more abrasive than sawdust got inside, so after cleaning off the top of the piston and the inside of the cylinder head, I'll put it back together and see how well it works.
Below: Top of the piston after a few cleanings with carb cleaner. Before cleaning, you could not see the metal. It was covered with a layer of mud, composed of sawdust and compressor oil.
Below: The cylinder head, now cleaned up.
I replaced the plug so that it will plug into the 220 volt outlet in the shop.
Below: I found some gasket damage (the center strip is broken). Fortunately replacement parts are not too expensive.
There is no telling how tired the other cylinder looks, and these parts are cheap, so I ordered two complete valve plate sets (part number VH900200AV). I'll replace these on the other cylinder as well. There is enough wear and tear to justify a complete rebuild.
Below: I also ordered two complete gasket sets (part number VH900300AV), one set for each cylinder.
I removed the oil sight-glass and cleaned the inside of it, so that the oil level can now be seen. Fortunately the oil was very cold and thick when I pulled it, so it didn't make a huge mess.
Below: Sight-glass before cleaning.
Before putting everything back together, I'll run the borescope inside the air receiver and see how much garbage is inside and maybe spray some simple green inside if it's too gooey inside. The air receiver has a drain valve that has to be operable or it will eventually fill up with water.
The follow-up post about fixing this Husky Air Compressor is here
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