1950 Merc Overdrive

[drgoetz]

I recently bought a 1950 Merc with overdrive. The electrics have been upgraded to 12 volts; Problem is....


While I was driving home the engine shut off while I was coming to a stop and I had already pushed the clutch in. Simple, just let out the clutch and roll start... nothing happened, the car just rolled on. I restarted the engine with the starter, put the car in gear and drove on. This happened twice more as I drove through town. The overdrive had been electrically disconnected and the overdrive (lockout handle) is pushed in.


All of the wiring and parts are intact, but electrically disconnected.



I would really like to use the overdrive. How do I fix this condition as I have little experience

[rjlester]

In order to disengage the mechanical side of the overdrive, you need to pull the OD handle OUT. That will also allow you to push start the engine. If the handle is pushed in, the overdrive will freewheel at all speeds on deceleration if the electrical side of things is disconnected.

It's recommended to only move that handle when you are at a standstill (if you are unfamiliar with how it all works).

Do you know how it has been electrically disconnected? One easy way is to remove the fuse, another way is to disconnect the governor wire.

Here is a link to a website with a pretty good description of how the Borg Warner Overdrive works: https://www.fordification.com/tech/overdrive.htm

There are other websites as well, I'm sure some other guys will chime with more info.

[Mac VP]

With the handle pushed in, you’ve mechanically enabled overdrive (although it won’t actually shift into overdrive without the electric solenoid working). In this mode, the freewheeling feature is active, which is why you couldn’t use the clutch to roll-start the engine. Pull the handle out and the transmission will behave just like a regular standard 3 speed. Unless there is some other malfunction in the transmission, you should be able to get the overdrive working provided you install/reconnect the various overdrive controls (governor, relay, solenoid, kick down switch,and all related wiring).

[rotorwrench]

The kick down switch is tied in to the ignition coil. It's designed to cut the engine just momentarily until the operating solenoid drops out of OD. Power is restored at the drop out by the opening of contact points in the solenoid as it drops out. It may not be dropping out as it should. You could also have an open wire to the coil or an intermittent connection. The wiring is in a swampy area so it takes a beating from poor weather conditions. The kick down switch is right down there with it so it has a hard life as well.

There is a rail switch on the early style mid century Mercury cars the cuts the operating solenoid power if the OD cable is pulled out. The OD shift rail is shifted back and pushes the switch to the open position. If it has a rail switch in place at the rear of the shift rail on the tail housing left side then it should be maintained as functional. Ford deleted the switch in the Mid 1951 Mercury transmissions so a lot of folks removed them and capped the port there.

[drgoetz]

I will make the pull out the od handle to lockout the overdrive. The wiring diagrams do not identify the wires (no colors) only a wiring harness for the entire unit... I need specifics.
Pulling the fuse will be easy, however I have not been under the car to check anything out.

[rotorwrench]

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This is a basic link for the Borg Warner system.
http://www.oldwillysforum.com/forum/...riveManual.pdf

These systems were used by a good portion of the US auto manufacturers at one time or another so wiring coding depends on the manufacturer. Color codes for the Ford, Lincoln, and Mercury cars were the same but Ford wasn't good about publishing color coded diagrams in their manuals. Diagrams are available from a number of sources though. On older cars with woven fabric wire coverings, the colors fade after about 10-years or so. It's hard to tell what color they are after 70+ years unless the wiring has been replaced much more recently with quality products. The coil control circuit has a white with red tracer wire from the coil to one of the rear side terminals on the kick down switch and a blue with orange tracer wire from the other rear terminal to the #6 terminal or orange solenoid wire depending on the solenoid vintage.

The kick down switch works just like it looks. The two terminals closer to the front mounted button side are spring loaded in normally closed contactor position and control the system ground to turn it on and off. The two rear most terminals are for normally open contactors that control the coil ground function for the momentary drop out. These switches can go bad after many years of swampy service.

My 1949 through 51 Lincoln and Mercury Overhaul Manual has the diagram with written in color coding for each wire. It doesn't list wire gauge though so a person has to replace wiring with the original gauge and not necessarily the gauge that is currently installed. Shade tree mechanics had a tendency to use whatever gauge wiring they have at hand to replace old wire that is losing it's insulation and breaking down. I've seen some pretty crappy shade tree fixes on these old cars.

[tubman]

These days, I would purchase a new OD wiring harness. It is a stand-alone harness and when I bought mine was reasonably priced. It'll save a lot of time and headaches rather than fooling around with an old faded and frayed harness or a bunch individual wires. The last time I looked kickdown switches were also available. Hopefully the relay, solenoid, and governor are good, as they can be hard to find and expensive when you do.

[drgoetz]

Thanks for all the replies... I think I've got it (?)
Next question;since the car has been changed to 12 volts will the solenoid and the governor still work or will I need to put in resistors?

Where do you find supplies or suppliers for Mercury's - I can find them for a Ford but not a Merc and there are differences.
This car is 72 years old...same family, 34,000 miles. Wiring will be a problem because coverings are coming off and exposing bare wire(s).
Any suggestions would be helpful.

[rotorwrench]

Two of the most well know Mercury parts suppliers have gone away in the last 5 to 10-years. It's not easy restoring these cars due to this. There are sources for many things though if a person knows where to look. Many Ford parts cross over but it's mostly drive train stuff that is shared with other Ford vehicles. A lot of rubber parts are available but not all. The Ford V8 parts sources try to keep some stuff. I deal with C&G, Dennis Carpenter, and Shoe Box central for what they have which is limited. A person has to check with NOS suppliers like Southside Obsolete (barnfind08 here on the barn).

The OD operating solenoid will work but new items from Fifth Avenue Internet Garage and a few other sources are available for 12-volt cars. The price is high so scouring the internet for NOS or good used stuff is not a bad idea. Most of the Borg Warner ODs used the same external parts well up into the 60s with a few still being used in the early 70s so stuff is out there. R11 ODs are larger and based on the T-85 heavy duty 3-speed so most later cars & pickups used them instead of the older R10 OD like the early 50s Ford products used. Lincoln started the trend toward the R11 since it could take more torque.

[Joe B.]

@ rotorwrench, thanks for the link and the info. I have been reluctant to try the retrofitted O/D in my '50 Custom Tudor until I find out more about it. Don't want to get stranded.

[drgoetz]

@rotorwrench..is Fifth Ave still around? (I heard Randy died 1.5 years ago.) I will contact them as well.
I have another 1950 OD from a '50 Ford. It is out of the car and sitting on a set of rollers. I thought I would learn from it and then work on the Merc.
One last question; can you push and pull the OD handle to let the free wheel work if needed?

[rotorwrench]

Randy did pass but I think the family is still operating the place.

When the handle is pulled, it shifts the sun gear back and locks the planet carrier to prevent operation of the planetary gears. This effectively mates the tail shaft up with the transmission output for standard drive. There is no freewheeling or coast function with the OD locked out. The engine will brake when the throttle is let up just like a regular 3-speed does.

[jeff34]

drgoetz, https://vintageautogarage.com/ is still around and has all the parts you need, as well as troubleshooting and instructions. Mac VanPelt www.vanpeltsales.com also sells these overdrive parts and is a wealth of knowledge.
Both options are expensive, but I've bought two solenoids now that came from "a running driving car" and both turned out to be crap.
I have heard that the 6V solenoid will work a few times on 12V but will fail at some point. Not sure if that's true or not.

[40cpe]

There have been testimonies on this site of those who have run a 6v solenoid on 12v for years with no problems. I have no personal experience with that situation, though.

[drgoetz]

OK---still have more questions.


Has anybody tried using resistors and have they been successful ?


Is there a problem with polarity (neg. vs. positive ground) ?


What is the story on the governor, mine has an electrical connection ?

Is it possible that both the solenoid and the governor can be rebuilt ?


Last question, not related to the OD; is there available and exploded wiring diagram for the entire car ? I have counted at least 7 so far.

[Dan in MI]

I have never tried resistors or negative ground so I won't comment on those.

The function of the governor is to complete the ground to the relay (needs to go through the rail switch if equipped and the kickdown switch). If the relay has power and the ground is completed the relay sends power to the solenoid to engage the OD. There is a set of contact points in the cap of the governor they are normally open when your vehicle speed is about 26 mph the weights swing out and a post closes moves toward the cap and closes the point. This completes the circuit and the wire going into the governor completes the circuit to the governor body which is grounded back through the trans and engine to the battery. The governor works with 6V and 12V as designed, you do not need to change anything. They are repairable and adjustable, I have the info if you chose to do this. Painted surfaces between the battery and governor may cause issues. I made a separate ground harness for the governor and solenoid and ran it to the body ground.

Solenoids can be rebuilt, Mel Gross here on FordBarn advertises them. Search for him in the Model A Swap Meet he sells various Model A parts.

[rotorwrench]

The system draws too many amps as it is for a dropping resistor to work well. Either use the 6-volt till it dies or purchase a 12-volt unit.

A person would have to try it for polarity to insure it pushes the actuator out when the operating solenoid is energized. It's likely not polarity sensitive but I've not had a need to try it.

The governor is a simple set of flyweights that move to operating position at around 23 to 25 MPH. The flyweights act to push the simple contact points of the switch closed to energize the system at that speed. That's all that' in there is the governor flyweights and the switch. When the car slows below the on speed then the flyweights retract and the switch opens to de-energize the system.

Anything can be rebuilt but it depends on cost of labor & parts for O/H versus cost of a new part.

I purchased one of the LARGE diagrams available on flea-pay years ago. They are 98% accurate. When I first rewired a 51 Merc some time ago, the wiring harness I purchased came with the correct wire colors and an excellent diagram sheet for each harness assembly. There are over a dozen different harnesses for this particular car depending on how it is equipped.

[rjlester]

I first learned about the Borg Warner OD in the summer of 2021, and I started researching immediately about it. I bought a used OD trans from a fellow I met, and he also gave me an original wiring harness from an early 50's ford sitting outside for decades. The governor, solenoid and relay were all original pieces and he included them all. I spend the winter of 21/22 reading about this overdrive system, how it works, and how to troubleshoot it. All of the links posted above I have read numerous times.

My friend with the parts was a godsend, and all of those parts I was able to take apart, clean, and put back together. The governor is a simple device, and I simply cleaned the contact points, and tested it with a drill and ohmmeter. The relay, I removed the cover, cleaned the contact points and put back together. The solenoid was VERY rusted inside, but I cleaned it out, cleaned the contacts and reassembled. The only part I bought new was a kickdown switch.

I now have a perfectly working OD, even took a three day road trip with it last summer, ZERO issues! You will never regret the time it will take to learn how it works. The Ford steps for troubleshooting are easy to follow, and you can narrow down any issues you are having. I did have a few snags initially, but cleaning all wire connections fixed most of those problems. I may have to replace the "new" kickdown switch, as I put oil in it, and I think that gummed it up - it's a bit sticky.

I hope you get your OD working, it really changes how the car drives and it's great to keep up with modern traffic on the highway!!

[drgoetz]

rj
Remember I have a 12v system. I took the governor apart with no problem, HOWEVER,
it is too cold for me to lay on the concrete in my breezeway to disconnect the solenoid and test it. I will do as you suggest and remove the relay cover for inspection. I also want to trace the wires back to the ignition switch and then to the coil. And, yes, I have reread the above posts several times.
This coming weekend I want to drive the car to a club meeting. When I get home I will put the car on jack stands and have a good look at the transmission and wiring.

[rjlester]

Sounds good. I wish I had a chance to post the Ford OD troubleshooting steps I have in a manual I found. My dad is in the hospital right now so it might be a while before I can upload those pics. They have an "underhood" set of steps and another one for under the car. With a test light they make it straightforward to finding any wiring, solenoid or relay problems.