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 isn’t easy, but possible.
My switch was leaking at the diaphragm between the 4 port base – I didn’t 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.
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 didn’t 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.
- 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.
- 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.
- 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.
- 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
Putting pressure switch back together.
by Bill Wolsleger
Remove the 4 port base and switch from the compressor.
Loosen cut out screw all the way back.
Clamp black plastic switch upside down by itself in a vise.
Put the two metal pieces with the 2 springs in place loosely and slide the base plate into place until the base plate sets down flat into its position. This takes some effort as you are stretching the smaller spring while making sure the bigger spring stays put.
Hold the plate in its position and clamp it with needle nose vice grips to keep it in place.
Now put the 4 port base in the vice right side up with the black metal plate on top.
Put the black switch in its place with vice grips still clamping it. This will allow you to get 1 corner screw in.
I then put a large flat blade screwdriver between the black metal plate and plastic switch to act as a wedge so when I remove the vice grips the thing doesn’t fly apart again.
Pushing down on the switch I slowly slid the screwdriver out until everything seated, then put the other 3 screws in.
Worked for me after a couple of tries.
Adjusted cutout to 110psi.
Very kind of you to contribute, Bill. Thanks.
And a big thank you to Mark E Estrada, who provided the following.
It looks like lots of people are/were in the same boat as I was. I pride myself on being able to fix anything and have been a mechanic for 35 years. This was really tough and I even ordered a new switch because I was gonna give up, so here are some pictures I took, because i got it back together and it works and doesn’t leak.
I did this because people on the internet have got me out of a bind a few times…pay it forward.
I took it apart because it leaked, and the points were peaked. Filing them helped a little. But sealing all the leaks so it doesn’t cut on and off all the time will make my repair last a little longer, and I have a new one, (not this brand) when it goes out.
Mark goes on to say “Good luck. You wouldn’t think a little switch would be such a bastard, but it is. It would help if there was a diagram, but I couldn’t find one so I had to put it together like a puzzle. Plenty of videos putting one on! If you need to watch a video to do that, don’t try this. You will be wasting your time.”.