Volvo Overdrive

M

Mike/Nebraska

Senior Member
I have a Volvo electric overdrive in my Model A but I can't get it to work. It's a 12v unit and my car is 6v but I was told before I bought it that it would work with 6v. I am running an alternator but I can't even get the solenoid to click but when I used my battery charger to get 12 v. it clicked. Anyone know how I can get this to work without switching to 12v. I have a ground strap running form the unit to the frame and a hot another lighter wire grounding the unit to the ****** case with the hot wire. It's getting juice with a test light. I'd appreciate any help I could get. Thanks in advance.
 
Hello Mike
Just a long shot the units from the factory had a diode between the 2 solenoid terminals, if it has cut it off and toss it, I have never had to deal with a voltage problem with them (many other problems) I suggest checking all wiring for resistance in its circuit.
 
Even though you read voltage at the solenoid, if the wire gauge is not
big enough to carry the required amperage, if won't have enough power
to 'pick' the solenoid. good luck !
 
I have Volvo ODs in all three of my Model A's. They run fine on 6 VDC but if the voltage drops just a bit below 6 volts the solenoid won't kick in. That's my experience on one of the cars.

Not sure I'd use a battery charger to test the unit but if the solenoid won't kick in using a 12 volt battery then it might be fried.

Who did your conversion/rebuild? Mine were done by Rich Little.

http://www.thelmasgarage.com/volvo.htm
 
The solenoid could be working ---but the oil level could be low, --does the solenoid click when it gets power

The old laycock od in my MGB (67)had a plate that could be removed to watch the solenoid move the lever, and the solenoid had a set of points inside--2 windings, one to pull it in, then the points opened and a smaller winding held it in---when the points got dirty the solenoid wouldn't pull in ---but I never worked on the later units so I don't know if the solenoid is the same in operation.
 
The diode is there to short circuit the high voltage created when the switch (or governor) is turned off. If it originally came from a negative ground car and you are using it on a positive ground car, then the diode needs to be switched around to match the polarity. A capacitor would also work to help cut down on the contacts arcing when the current is turned off.

Have you run a jumper wire direct from the battery to the solenoid to see if it clicks in?
 
Mike/Nebraska said:
I have a Volvo electric overdrive in my Model A but I can't get it to work. It's a 12v unit and my car is 6v but I was told before I bought it that it would work with 6v. I am running an alternator but I can't even get the solenoid to click but when I used my battery charger to get 12 v. it clicked. Anyone know how I can get this to work without switching to 12v. I have a ground strap running form the unit to the frame and a hot another lighter wire grounding the unit to the ****** case with the hot wire. It's getting juice with a test light. I'd appreciate any help I could get. Thanks in advance.
Click to expand...

As mentioned, check the voltage at the solenoid, what does it read? Additional grounds are a great idea but if the wire supplying the voltage is not allowing maximum voltage to the unit all the grounds in the world won't help.

The solenoid does work on 6 volts IF the solenoid is in good condition. Try using a good, charged, 6 volt battery and see what voltage is at the unit. See what the voltage is at the unit when you attempt to engage it.

Report back findings.
 
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