1955 Thunderbird Clock Repair

[doug7740]

I have removed the clock from my 1955 Thunderbird and I want to see if I can repair it. Over the past 4 years the clock has been operating without any problems, but recently it seems to stop. After I set the time it will operate normally once again. The clock is a 6 volt positive ground manufactured by Motochron. Before I attempt to disassemble the clock, and so I don’t damage anything I have a few questions.



How do you remove the set knob from the set stem so I can remove the clock lens?



How do you remove the clock assembly from the metal case?

Has anyone successfully repaired one of these clocks or is a quartz conversion my only option?

doug7740
1955 Thunderbird Blue

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[Gary Tayman]

Doug, your best bet would be to wrap this set up and send it to a place that specializes in rebuilding clocks. I'll give you two places -- Instrument Services Inc. in Roscoe, Illinois, and D & M Restoration in Greenville, South Carolina.

Instrument Services specializes in restoring clocks, and they make the movements for quartz conversions. They sell these movements outright for Borg clocks, and I believe they are affiliated with Borg in some way, but yours of course is something else. They can definitely take care of you, but don't be surprised if they tell you it might take 6 months to a year! Their backlog is crazy.

D & M specializes in gauges and instrument clusters. They can rebuild clocks, and they also install quartz conversions. They use movements from ISI, so you'll get the same product either way. They may be considerably faster.

All that being said, I offered quartz conversions for awhile. I very highly recommend it! If your car is a 100-pointer that must stay totally original down to the screw heads, stick with original. Otherwise the quartz movement is excellent. I've been very happy with them. I got out of it for a few reasons -- one is that they sell me the movements for the same price they would offer to you; I only get a discount if I buy in great quantities. So profit margin is slim. Second, they only sell movements for certain cars, meaning I was turning away more customers than I could accept. They offer training for the others, and will only sell the others to certified-trained dealers, but the training is expensive -- just for airfare and hotel, and time away, before even asking the cost of the class. But D & M can do these.

With the quartz conversion, the clock looks original but is silent, and draws less current from the battery. It also keeps time -- no continual adjustments every day or two. I've had one in my 1964 T-Bird for around 15 years and still going strong.

 

[doug7740]

Gary,

If I decide to send the clock out for repairs, http://www.clockwks.com/Tbirdx.html offers a mechanical restoration for $79.95 and a 6 volt quartz conversion for $219.95.

Sometimes clock repair is simply a matter of opening, cleaning, and lubricating. That is not usually the case, but it does happen. Since I do not have a Motochron repair manual, it will take some investigation to gain the knowledge needed to perform the repair, that's why I'm asking questions before I attempt to repair the clock. I'm sure that the process is not very different from most other automobile electric repairs that I have done in the past. And when it is done, I can enjoy the satisfaction of having personally restored a system to function as originally designed.

doug7740
1955 Thunderbird Blue

 

[Gary Tayman]

Gary,

If I decide to send the clock out for repairs, http://www.clockwks.com/Tbirdx.html offers a mechanical restoration for $79.95 and a 6 volt quartz conversion for $219.95.

Sometimes clock repair is simply a matter of opening, cleaning, and lubricating. That is not usually the case, but it does happen. Since I do not have a Motochron repair manual, it will take some investigation to gain the knowledge needed to perform the repair, that's why I'm asking questions before I attempt to repair the clock. I'm sure that the process is not very different from most other automobile electric repairs that I have done in the past. And when it is done, I can enjoy the satisfaction of having personally restored a system to function as originally designed.

doug7740
1955 Thunderbird Blue

If ou indeed do it yourself, keep in mind that the single biggest problem with these clocks is the points for the solenoid. Most clocks fail after the battery goes dead, and what happens is that the points make contact, there's not enough voltage to kick the solenoid, and so those points burn up. When in good condition they're self-cleaning.

 

[doug7740]

Gary,

That is why I need the information on how to disassemble the clock, can you help me with this? From what I have read, unlike later model automotive clocks which worked with a spring loaded mechanism that is “cocked” by an electro-magnetic relay, the 1955 & 1956 Thunderbird clock has a constantly running electric motor. That would mean that there are no points in a 1955 & 1956 Thunderbird clock. Is that correct?

doug7740
1955 Thunderbird Blue

 

[doug7740]

I was able to remove the clock assembly from the metal case and I will update everyone of my progress. Any suggestions or tips are still welcome.

doug7740
1955 Thunderbird Blue

 

[doug7740]

I was able to repair and calibrate the clock on my 1955 Thunderbird. Attached is an article I wrote explaining how I performed the repairs.

doug7740
1955 Thunderbird Blue

 

[64ZCODE]

This is really great, Doug. I really appreciate your step by step description, with photos, and attention to detail!

 

[LosAngelino56]

I was able to repair and calibrate the clock on my 1955 Thunderbird. Attached is an article I wrote explaining how I performed the repairs.

doug7740
1955 Thunderbird Blue

Hi Doug,
How did you remove the set knob? I have the same issue but on a 56.

I hooked it up to a 12v and it runs way too fast and not smooth. Almost thought I had a 6v clock at the speed. However closer inspection on the back indicates it is a 12v. I hope to disassemble it and oil it like you did.

 

[doug7740]

To remove the set knob, hold the shaft with needle nose pliers and loosen the knob. Unless you need to remove the clock lens to refinish the black dial face or clock hands, you do not have to remove the set knob to perform the repairs that you have indicated.

The motor is attached to the clock by two slotted screws. After you remove those screws, just lift the motor off of the clock assembly. After the motor is removed you will then be able to clean and lubricate the clock assembly.

doug7740
1955 Thunderbird Blue

 

[LosAngelino56]

To remove the set knob, hold the shaft with needle nose pliers and loosen the knob. Unless you need to remove the clock lens to refinish the black dial face or clock hands, you do not have to remove the set knob to perform the repairs that you have indicated.

The motor is attached to the clock by two slotted screws. After you remove those screws, just lift the motor off of the clock assembly. After the motor is removed you will then be able to clean and lubricate the clock assembly.

doug7740
1955 Thunderbird Blue

Thank you. I will try that.

 

[LosAngelino56]

Hey Doug,
Oiled the spots you suggested.

However My clock still turns really fast. But when I reverse the polarity it spins backwards but perfectly timed. The motor ticks properly when backwards but just spins when positive to positive. Any ideas of how to troubleshoot?

 

[doug7740]

The clock is polarity sensitive, by connecting it in reverse you are turning the clock mechanism in reverse which could damage the clock's main spring. I just uploaded the following video to show you how fast my 6 volt positive ground clock motor turns.

I hope this helps.

doug7740
1955 Thunderbird Blue

 

[CSPIDY]

Doug, you are now the go to guy for 55 clocks, good show buddy

 

[zeroroadkill]

I have removed the clock from my 1955 Thunderbird and I want to see if I can repair it. Over the past 4 years the clock has been operating without any problems, but recently it seems to stop. After I set the time it will operate normally once again. The clock is a 6 volt positive ground manufactured by Motochron. Before I attempt to disassemble the clock, and so I don’t damage anything I have a few questions.

View attachment 2782

How do you remove the set knob from the set stem so I can remove the clock lens?

View attachment 2783

How do you remove the clock assembly from the metal case?

Has anyone successfully repaired one of these clocks or is a quartz conversion my only option?

doug7740
1955 Thunderbird Blue

Yes, to remove the clock body from the trim remove the 3 small screws and pull the trim off. Now remove the case terminal nuts. Case can be removed (be careful with glass). The fine hair like brushes bend very easily and usually are burnt where contact the armature because the motor is a constant “on” state and forces tension to the spring driving the timing gear. The armature only spins when the spring tension decreases. The armature and brushes need to be cleaned and burnished. Tough job. I removed the armature windings to clean and tried not to bend the brush wires, a big challenge! If they fall off the mounting stud (plastic) they are VERY hard to reinstall without bending! I did notice a slight discoloration on the brush wires where they contact the armature probably from heat due to constant current to the brushes. I got it running after several brush install tries and made sure both dual wire brushes touch the armature equally and lubricating the stuck gears ⚙️ BUT it did stop after about 36 hours. I believe it needs new brushes. Where to get???

 

[Tater Salad]

I was able to repair and calibrate the clock on my 1955 Thunderbird. Attached is an article I wrote explaining how I performed the repairs.

doug7740
1955 Thunderbird Blue

Great info Doug.
Just to clarify, when converting to 12V does the wire switch to the positive post or the only change is the Tab moving to negative post?
Also, how does the tab come off the + post? I don't want to break it from over pulling.

 

[doug7740]

When converting to 12 volts the polarity for the clock must be changed to negative ground from positive ground. You will have to remove the clock to do this. Once the clock is removed you will have to lift the case to switch the ground tab from the positive to the negative power input. To remove the back of the case, take the retaining nuts off the power inputs and remove the three screws around the circumference. There is a little tab that is designed to be positioned for positive or negative ground. Position the tab for negative ground. Major damage will occur if it is powered up in reverse polarity. Install a 125 ohm, 10 watt resistor in series with the 6-volt clock to drop the voltage to 6 or 7 volts.

doug7740
1955 Thunderbird Blue

 

[Tater Salad]

Thank you for the clear explanation. I was attempting to move the tab from behind the dash.

 

[hotrodgss1]

Doug, in the write-up you provided you wrote "To remove the set knob, turn it clockwise while holding the shaft with needle nose pliers." Before I attempt to remove mine (1956 T-Bird), I just wanted to confirm, that the set knob needs to be turned CLOCKWISE, and NOT counter-clockwise.

 

[doug7740]

To remove the little set chrome knob from a 1955 or 1956 clock, turn clockwise. The 1957's have a right hand thread that you have to turn counterclockwise to remove.

doug7740
1955 Thunderbird Blue