Need help rebuilding a pressure switch for a craftsman 106.153780

by Mario
(St. Louis, MO)

Need help rebuilding a pressure switch (yes, I know it's a lot smarter to buy a new switch :-))


I just picked up an older craftsman 106.153780 compressor single stage, 2 cylinder, 230V Doerr motor.
I won't go into the gorey details, but now it runs fine but now I need to re-assemble the pressure switch. (Yes, I know that the problem was probably the unloader valve, but I hadn't found this site before I started "fixing" this compressor!?!?).
Stretching one tension spring and compressing one compression spring and holding everything in place while trying to assemble the switch is proving to be a "challenge".
I am about to try to hold everything in place with some 'bailing wire' while I assemble the switch in the housing, but was wondering if anyone knew of any 'secrets' used in the original assembly .... like, is there someplace to insert a pin to hold everything in place during assembly?
Note; I will probably buy another pressure switch, but I am just stubborn enough to figure out how to re-assemble the original!
By the way, does anyone have a recommendation for an economical replacement switch? it looks like I can spend anywhere between $12 and $150 .... there has to be a "sweet spot" in there somewhere :-)

I really appreciate all the info on this site, and all the folks who have taken the time to make inputs!
Mario

Comments for Need help rebuilding a pressure switch for a craftsman 106.153780

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May 16, 2016
Holding pressure switch together to assemble
by: Anonymous

I had the same prob with my pressure switch too., What I did was got some long enough tie wraps and held it that way.After pushing together the spring and assembly by force I crisscrossed tie wrap vertically one way and horizontally another holding the assembly together enough. So when I put the screws to mount it ,just enough close to the base I cut them and pulled the tie wrap out. It worked for me that way. Pull one direction.

Aug 05, 2015
Medal?
by: Bill

I'd always welcome a medal, Chris. And I'd give one right back for the time you took with this excellent update.

Cheers,

Bill

Aug 05, 2015
In case you were still wondering...
by: Chris C.

... I did this to my also just salvaged compressor of the same (or older) vintage (Sears 106.71725) that I got for $30 because of its leaking air tank.

Basically, you need to stop trying to assemble the bottom plates with the little spring BEFORE assembling the switch and pull the loose end of the little flip plate spring AFTER it's been assembled.

Align all bottom parts flat, insert the pressure adjusting screw and plate and the main spring into the bakelite contact holder and hold it in place while you align the gasket from the valve properly with the screw holes and make sure the switch actuating lever end is correctly placed as it should under the bottom plate channel, then screw everything together, it should lie perfectly flat.

After that take a piece of thin steel wire and fish / hook the loose end of the little plate spring in and, using a pair of pliers, pull it over the spring stay of the bottom plate.

You may also need to pry the flip plate up using small screwdrivers so that it pivots properly ( to test, push down the little nib of the bakelite actuator protuding off the top of the bakelite contacts assembly).

Using a small flat file, I was able to get the contacts cleaned enough for the whole thing to work, but you may need to slightly bend the contacts if you filed them a lot for the motor to start properly. When open you don't need much more than about 1/16 of an inch in between contacts. The wider the contact, the less chance of arcing but the poorer the contact when the bottom plate snaps the contacts closed.

Hope I make sense and that it will help. I need to find a cheap way to fix my leaking tank problem now. I'm determined to get this beauty running again :-)

I'd also like to thank the owner of this site for making it possible to post anonymously. You deserve a medal for promoting free speech :-)

Feb 03, 2015
pressure switch
by: Doug in s.d.ca

Ah, what fun...

You may need to make a couple of tools to do what you need. Maybe out of tin cans or even bicycle (thin) wrenches. Whatever you have.

Pretty much any pressure switch should work, so long as it's in the right range, and has big enough contacts to handle the load. Does the switch run the motor directly, or does it have a starter?

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