A few days ago I posted about buying this kit - Air Compressor Pressure Switch, Safety Valve, and Gauge - $12.50 on Ebay.
1/4" BSP 4 Port Single Phase Air Compressor Pressure Switch + Safety Valve Gauge | eBay
...To repair my year 2010 Harbor Freight 10 gallon compressor.
I got the kit installed. Comments if anyone in the future is considering this:
The time spent wouldn't be worth it in a hourly-wage environment. Just get a new compressor and give this one, and the kit, to some kid who can put a couple of weekends into fixing it.
I got it right in ordering the BSP (British Standard Pipe thread) version of the control instead of US-spec threads.
This control is widely used. This one is 15 amps 110/220, the other common one on Ebay is rated 26 amps and might make a better replacement. While Ebay shows 'up to 175 psi' this is adjusted and labelled 115 psi, and includes a new gauge redlined at 120 psi.
The hole in the top of the control isn't the air pressure adjuster, its the holddown screw for the cover.
This kit has a name brand on it, HF's was unbranded. Only one difference but it took hours to resolve: there's a piece of quarter inch copper tubing that goes into the bottom of the control and this branded kit used a larger diameter compression nut there. While the copper tubing was generic US-spec, the tube had to be replaced, with a new compression ring/donut, to attach it to the control unit. I tried carefully slicing off the old compression donut and replacing it but the new compression donut wouldn't seal. I had to go to town and get a new 10 inch piece of quarter inch copper tube. Then the other end of that copper tube is flared. I had the flaring tool but had to ream and burnish my new flare before it would seal. The compression nut at the lower, flared end of the tube was so poorly made that it slipped, didn't even strip, on the threads it mated to. That explained why I found gasket paste there when none should be needed at a flare fitting. Plenty of teflon tape on those threads compensated and I finally got that compression nut installed securely. Bah.
If anyone makes this replacement I suggest lay the control valve on its side like some later compressors, rather than upright. And pre-wire the wall cord to what will be on the lower side of the control before screwing the control onto the tank. This change makes it unnecessary to work with a mirror and flashlight to connect the copper tube in what would have been in tight space underneath the control, now it's accessible on the side facing toward where that tube is headed.
Ok, the repair made it like new - new control valve, new safety bleedoff, and even a clean new gauge - and the compressor is back in service.
Ebay photo. You can see in this photo how installing the control on its side as oriented here makes it easier to attach the copper tube to the compression fitting, contrasted to the original vertical orientation for the control with that fitting crowded under the control, right next to the vertical compressor outlet pipe.
