1950 ford v8 overdrive wont engage at times

[joe 1950]

ive owned this car 20 years went through this unit time and time again know the electric part of it like a book worked good for a long time just the last couple years wont lock in have 3 good used solenoids tried all them replaced relay also o-d cut out switch gov. works perfect almost seams as though its something in trans can take it and drive one day and the next day it wont I can see the amp gauge drop when it wont and when it does engage gauge drops and goes right back up I just don't believe its electrical

[rotorwrench]

It sounds like you've addressed the components but what kind of shape is the wiring harness in? The operating solenoid has a main kick in coil that draws a good bit of amps but it kicks out at full extension which allows the holding coil to then activate. If the holding coil doesn't kick in due to problems with the contacts or coil then the main coil will still be drawing amps. If the pawl up inside the overdrive unit isn't engaging a slot in the balk ring properly then it could be a problem in there too. The balk ring can lose tension over time and cause engagement or disengagement problems.

[donald1950]

you might check the lock out arm on the trans to see if it is in position. i bought my 53 several yours ago and had that problem and the cable was out of adjustment. also note that due to the way the lock out and the electrical work on these cars that even when the OD handle is pulled out and the OD is locked out, the solenoid will still operate and show a current draw when the governor engages at 27 MPH.

i have also had experiences that even though the AMP gauge showed a draw, the way the relay was wired to the ignition switch was not able to pass enough current to fully energize the solenoid and push the prawl enough to engage the OD. with that i ran the feed wire for the relay directly to the battery and added a circuit breaker between the battery and relay fuse for extra protection...

[LuckyFordGuy]

Check the genitor brushes I had same problem would charge then it would not new brushes worked great Rog

[rotorwrench]

Either Ford or Borg Warner decided that the rail switch was redundant in 1951 or 52 so they deleted it. That's what keeps the solenoid from operating when locked out. The earlier cars had the rail switch clear back to the Lincoln applications when Ford first used the design.

[joe 1950]

Sponsored Links (Register now to hide all advertisements)

I have all new wiring harnesses their good and the in and out o-d cable is new and adjusted perfect but I like the idea of the voltage drop from ign. switch i'll try that next it also was suggested from van pelt

[STEVE O]

I owned a 1950 Plymouth for 36 years that I installed a 52 od trans into with all 50 Ford controls, which I just sold 4 years ago. It would never lock od until I drove a little bit to get the voltage peaked, which while driving with the headlights on took longer. When you would let off the throttle to try to engage od you would see the amp meter go to discharge. If I would have made a new harness with larger wires I think it would have helped. I often wonder if I would have put a 8 volt battery in it if that would have gave a little extra voltage to kick the solenoid.

[Cecil/WV]

My '50 Ford gave me intermittent engagement problems for thousands of miles over a few years until I had my generator checked and replaced the voltage regulator due to the low voltage and since then I have driven it to SD and other trips without a skipped beat. My voltage runs near 7 volts. Perhaps the solenoid is a bit weak after more than60 years of use, but it never hesitates!

[Mike51Merc]

The solenoids are very sensitive to voltage drops. Anything less than 6 volts and they don't like to engage.
I chased an intermittent OD problem for years. My symptoms were that the OD would sometimes fail on my way home from cruises------ eventually discovered that it was because it was dark and my headlights were on!
The problem for me was that the wire supplying power to the solenoid was too thin of a gauge, everything else in the electric system was OK.

[donald1950]

also having 12 ga wire from the battery source to the relay and then also 12 ga from the relay to the solenoid is essential. having the relay powered from the ignition switch or the coil is how Ford designed it, BUT, the wire powering the ignition switch is, as i found on most of my cars, was 14 ga. (that runs the coil, raido, gauges & overdrive). had one care someone rewired the whole car with 16 ga wire and all the same color (try tracing that mess). i also noticed that with one car it had 16 ga wire from relay to solenoid and after about an hour of driving the wire would get hot thereby increasing the resistance to current flow in that wire and would not pass enough current to hold the solenoid in. the heat turned the wire into a resistor......
noticed also that my current 1953 Victoria had the relay wired to the coil and when the OD was engaged, the coil was under powered and had a bit of a miss.... that is why i took relay power straight to the battery and that cured intermittent OD operation and missing when in OD......

[Planojc]

I have found many relays with as much as a two volt drop due to bad connections inside the relay. If you remove the cover you will see that all connections are made with rivets and over the years corrosion sets in and you get a voltage drop. The rivet connection where the fuse holder connects is usually a place to start. I clean all rivet connections and using a good flux, solder all these connections. You can also have a drop through the ignition switch. I have a test setup with a battery and sol. that I can use to check the voltage going in and out of the relay and after doing the above, if you have proper output from your charging circuit it will work every time. Another thing that helps is to go with an alternator, even if you are running 6v.

[joe 1950]

i ran a 14 gauge wire from battery to relay worked good for @ 10-12 engagements then quit I have also tried a different relay and battery voltage is 6.9 volts I will try another solenoid I have

[Mike51Merc]

14 ga is too thin. Get a 12 or 10 Gauge wire.

[donald1950]

12 Ga is good, 10 Ga is better.... from battery to relay AND from relay to solenoid... especially for 6V systems..

[joe 1950]

UPDATE : installed another good used one after cleaning the points worked great going to car show this weekend about 50 miles away at least I feel good about the rest of the system , I hope , thanks for the extra input