A compressor reed valve failure is a common complaint sent in by people that have an air compressor that continues to run, but that will not build air pressure. Here is what you can do about that.
On behalf of all of us, our thanks to Jason Antonacci of North Augusta, SC for sending in a post and a diagram along with it, addressing the issue of air compressor reed valve failure. The diagram (shown below) is from the manual for Jason’s compressor. The concept will apply to any compressor that uses some sort of reed valve setup for intake and high pressure air compressor valves.
Here is Jason’s drawing, his questions, and my response.
Expanded view of compressor pump
I have an air compressor that recently stopped building pressure beyond 40 psi. After reviewing your troubleshooting steps and documentation I had hope that the compressor could be rehabilitated. Thank you for your site, it has been an invaluable resource.
On disassembly I discovered the top, yoke shaped reed had failed: snapping in the middle. The bottom, tongue shaped reed is OK. If I can locate reasonably priced replacement parts, I’ll rebuild.
This brings me to my question. All gaskets appear to be a fibrous material (cardboard?) sandwiched between adhesive material. Not all of the gasket came off cleanly, so bits are stuck here and there on both surfaces.
What is the suggested method for re-finishing these surfaces for a new gasket? I was thinking a wire brush attachment on my drill. Do I need to be concerned about debris in the cylinder and if so how can I prevent/remove it? Lastly, what kind of lubrication?
Apparently this reed valve design is prone to failure based on the number of similar complaints. Maybe I’ll build a Franken-compressor, mounting the 5hp motor w/ a belt driven compressor of another make?
I responded: Thank you both for the compliment on my website, and for the photo / sketch of your compressor head.
Reed valve failure is a common complaint for many of the lower cost, DIY type air compressors on the market.
I would be hesitant about wire brushing the surfaces due to the potential for damage to the metal, and consequential difficulties in re-sealing. If you proceed in so doing, work slowly and carefully so that the metal isn’t scratched.
Consider using a liquid/cream cleaner like “Goo Gone”, or similar, that will dissolve adhesives and sealants. Read the directions and use with care, please.
I would very much be concerned about getting debris into the cylinder. Before you cover it with clear plastic or the like, and / or before you reassembled, blow it out with compressed air (difficult when your compressor is disassembled, I know) to ensure that there is no debris in there to possibly scratch the cylinder surface or damage the seals.
Others have manufactured their own compressor reed valves out of paint scraper blades. See the sitemap page for a link to those directions.
Thank you again for a very good post, and I shall use it to help other visitors that visit this website.
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I have an older craftsman compressor ,25 years, #919.155730. The reed valves gave out. You can no longer purchase the reed valve plate and casket by it self. Is there anywhere I can go to have the old reed plate repaired. I hate to throw the unit away. The compressor and tank are still in good shape. Can I purchase a replacement compressor and reuse the exsisting tank. What would you do. Thank you.
My D.I.Y. repair: I made a replacement out of a 0.3mm feeler gauge, cut to size obviously and no deformity during cutting. That gave me the exact thickness and strength to bend compared to the old ones. New is ideal but it wasn’t an option at the time. It was back to normal operation again thankfully and I could then purchase some replacements for when I need them again in the future.
Where can I find said Reed parts? It’s a Harbor Freight compressor. 21 gallon model # 47065. And are the things that look like silicone bumps included with the gaskets? And are the 2 items that appear to be alignment pins included? I lost one as seen in the picture?
I have a Campbell Hausfeld 125 psi 13 gallon 4 hp. It only fills to 20 psi keeps running will not go past that. I took up the top today to look at the piston and seen that as you look at the picture one of the pieces broke off. Now I cannot say for sure if it did not break off as I took it apart but I doubt if that is the case.
I have it’s fairly new 21 gallon 2.5 hp air compressor my question is my reed valves are burnt scorched but not broken what causes that and should they be replaced as a result I’m having trouble with the compressor as it builds air but the check valve located on motorhead is becoming much hotter than I believe it should be as well as the compressor itself keeps blowing fuses I understand most courses are air leaks behind or near the check valves which I do not have the check valve opens and closes as it should so I’ve been… Read more »