Putting A Pressure
       Switch Back Together



From time to time I get an exceptional post from folks visiting this site. Here's one about putting a pressure switch back together. My visitor writes... Problems putting a compressor pressure switch back together? It isnt easy, but possible.

My switch was leaking at the diaphram between the 4 port base - I didnt expect any real issues as I could tighten down the 4 bolts and it would be alright for a while. After looking into getting a new switch and learning more about them, I figured I'd just try to fix my existing one.

I wish I would of looked for any pics or diagrams that would show a breakdown of how the switch is laid out internally before I tried it though - I wouldn't of messed with it as, despite extensive searching, there is nothing! In hindsight, I could of just removed each of the 4 allen bolts individually and added some locktite and the pressure switch would of probably been fine.


this is a compressor pressure switch -  putting-a-pressure-switch-back-together.html

So, if you're one of the few that has taken one of these Lefoo type switches apart - the guy who posted on 8/8/14 ('putting it back together') had some helpful info.

I have a 175 psi switch and didnt realize the spring pressure would of been so great. I did not intend to take it all apart, but after removing the 4 allen bolts, it separated from the base and I could not squeeze it back together, and trying to line up the bolt holes at the same time seemed impossible. At one point, it basically flew apart. At first, it seemed like it could go back together 2 or 3 different ways, but after looking at it closer, it can only really go back together one way.

  1. First thing that I needed to do was to back out the cut in / cut out spring all the way. My adjustment screws were covered with silicone or something, so I had to remove that first but it was the gold screw (to the left) - I backed it all the way out so there was no tension.
  2. Then starting with the black flat plastic piece, there is a slot for it to slide up into, with a cut out for the spring. The top of it should stick out between where the wires attach.
  3. Next, holding the main plastic body upside down, the metal plate with the tab that extends out to the unloader valve goes on, followed by the long metal plate with the round depression. There is a cut out in the main plastic body for the 2 tabs of the metal plate to fit into. As the other guy had posted, leave the small spring between the 2 metal plates unhooked at this point.

  4. Take the metal base, diaphram and 4 port section and line it all up on the main plastic body. After its all bolted back together, take a small hook and stretch the small spring over the tab. Its a pretty heavy spring for being so small, so it takes a bit of effort.

After it first flew apart, I figured I could find a breakdown of the switch easily online - but after relentless searching, I was sadly mistaken. I did find a few pics of people who were in the same boat with their switch in pieces... Between looking at countless pics and trying to test fit it together several times - I was still a little uneasy I didnt have it exactly right, but like I said, it can only really go back together one way. While it was apart, I found some corrosion on the metal base where it met the diaphram - pretty much where it had been leaking - so I cleaned it all up.

Relieved to report that after putting it all back together and testing it out, it worked with out issue and has not leaked at all. Its taken some work to get the cut out set correctly, but other than that - it is working as it should.

Hope this might help someone.

I sure expect it will. Thank you, anonymous contributor. Bill

Got a tip or two for putting a pressure switch back together? Use the form and please, upload medium or low resolution photos to show everyone the steps you take. That will help us all.

Thank you, Bill.


Putting a compressor pressure switch back together.

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