Starter Solenoid Repair

 

    Have you ever turned the key on your VW only to hear a "click" nothing but silence. . .??  If you have, there's a very good chance that your starter solenoid is bad.  If you can arc the two poles on the starter motor and it turns, the motor itself is good, but your solenoid is shot.  What causes this??  Carbon deposits and corrosion keep the electricity from flowing through the leads.  Burning of the contact pads is also caused from holding the key in the "start" position too long.

    Guess what; you'll be lucky if you can find a parts store that has just the solenoid.  99% of the time, you have to spring for a whole new starter. :-(   Call me "The King of cheap", but I just hate to have to buy a new starter assembly when it's only the solenoid that's worn out . . . or is it??  Why not repair it??

    The starter solenoid is a very simple electromagnetic switch.  Plug 12V DC into it and it jumps about 3/4" inward which moves the starter gear into position on the flywheel (this is the "click" you hear).  As it hits the bottom of it's movement, a copper plate makes contact with the back-sides of the two large terminals bridging power from the battery to the starter motor itself.  If all goes well, the starter engages and you're off.  If there is corrosion and carbon build-up on the contact plate and the back of the terminals, you're not going anywhere.

    Here's a procedure to repair the copper contact plates.  First remove the solenoid from the starter motor itself.  It's held on with 2 screws.  The photo below is of 3 solenoids from VW starters.  The two outer ones are from standard non-self supporting starters found on 99% of the air-cooled VWs out there.  The center one is the one that's worn.  It's off the heavy duty self supporting starter found on automatic  Type 4s.  Of course this is a rare item so I must repair it!!

solenoid-line-up.jpg (157897 bytes)

    There are two screws that hold hold the plastic top on.  Remove them.  Then place the solenoid in a vice to hold it steady.  You'll need a soldering iron to melt the solder on either side.  While the iron is melting the solder, apply pressure UPWARD so that as it melts the solder you will begin to raise the top.

melting-solder.jpg (169147 bytes)                    melting-solder2.jpg (175579 bytes)                    raising-top.jpg (181494 bytes)

    Once the top is removed, you will be able to see the copper contacts which are likely burned, corroded, or have carbon deposits on them which prevent the flow of power through them.

base-contacts.jpg (175315 bytes)                        top-contacts.jpg (176991 bytes)

    Now use a jeweler's file to file down the corrosion and carbon deposits off the base contacts.  The top contacts are in a recess so you can either use sand paper or a Dremel tool to remove the corrosion and carbon deposits.

base-filed-clean.jpg (185877 bytes)                    base-sanding-clean.jpg (177739 bytes)                    top-dremel-clean.jpg (179340 bytes)

 

    Now that the contacts are clean, it's time to replace the plastic top and re-solder everything back together.  First replace the two screws so that it's seated to the base.

top-replaced.jpg (169659 bytes)

    Now you'll need to re-solder the two connections back in place.  Hopefully, you are a better at soldering than me :-)

resoldered.jpg (185306 bytes)

    Now your solenoid is repaired and should work as good as new.  Replace it on the starter motor with the two screws and also place the starter motor lead onto the shorter of the two poles.  Viola!!  Your starter assembly is as good as new!!

 


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Revised: August 28, 2003 .