Reed Valve Failure

Reed valve failure; one of the most frequent complaints that I get sent by people that have an air compressor that continues to run, but that will not build air pressure.

I would like to extend my thanks to Jason Antonacci of North Augusta, SC for sending in a post, and providing a diagram along with it, addressing the issue of air compressor reed valve failure.

The diagram provided 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.

compressor reed valves

I have a Harbor Freight purchased, Central Pneumatic 96447, air compressor that recently stopped building pressure beyond 40 psi. After reviewing your troubleshooting steps and documentation I had hope 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 the 94667 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.

Bill says...

Thank you both for the compliment on my website, and for the photo / sketch of your compressor head.

Reed valve failure seems to be 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.

Consider using a liquid/cream cleaner like "Goo Gone", or similar, that will dissolve adhesives and sealants. Read the directions and use with care.

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.

Thank you again for a very good post, and I shall use it to help other visitors that visit this website.