Restore a dead solenoid

[chainsaw_louie]

Woodmizer's and probably other sawmills can have several of those 12 v solenoids that switch on the power to the hydraulics and other electric components.  Inside the case are silver contacts which after many cycles get a buildup of debris from the arcing and will no longer conduct electricity . 

I've had good luck with opening them up, cleaning the contacts and re sealing them. 

My process:

1. Mark the two sides of the plastic case so that its clear how the two halves of the plastic case fit back together......or take a picture 

2.  Drill out the end of the 4 rivets , use a dremmel if the rivet spins.  Being careful not to break the fragile corners of the plastic case, push/punch out the rivets . Slide off the case. 

3. Remove the 4 screws that are between the connector lugs. 

4. With a soldering iron , heat and separate just one (of the two) connection wire from the backside of the plastic base. Gently fold back and separate the solenoid contacts.

5. Using a small, fine-grit grinding stone in a dremmel or a blade etc scrape and clean and smooth the four silver contacts.

6. Reassemble the contacts and put the four screws in to hold  both sides together, then resolder the wire from step 4. Put a small bead of sealant glue (e6000 or similar) around where the two plastic halves of the case meet. Push in the rivets , add more sealant around the rim , hold the unit together in a vise or clamp until the sealant dries. Done.