1971 Mark III Headlight Door Actuator/Motor Replacements

[stovebolt1]

Howdy;
I'm probably beating a dead horse (no offense to the horse community), but I need to replace one of the headlight door motors on my 1971 Mark III. I've been looking around and I've found rebuilt OEM motors for around $800 a pair. I've also found new motors that claim to be for both the Mark III and the 1969 Thunderbird which are priced at less than half the OEM motors. Ideally I'd prefer to buy just the one that I need.

Mark III P/N: C8SZ 13A167-B

I cannot tell if the Thunderbird part number is interchangeable with the Mark III. Unfortunately I don't have the Ford master parts catalog. The two look very similar.

Anyone have any experience with replacement motors and, if so, recommend any vendors?

 

[Action]

I can help you at some point. I have both the LM MPC and Ford MPC.

However my wife went into the hospital over the weekend and my new temporary digs are on the second floor of the hospital until she gets out.

Action

 

[stovebolt1]

I'm sorry to hear that, our thoughts are with you. I tested the actuators with the old Mity-Vac and the passenger side is definitely leaking, but the driver side holds a vacuum for quite a while.

 

[Action]

C8SZ 13A167-B application is
Only 1969 to 1971 Mark III

1972 to 1976 Mark IV only uses one vacuum motor and that is D2LY 13A167 A which was replaced by D5LY 13A167 A in 1975.

1967 & 1968 Thunderbird use C7AZ 13A167 A (2)
1969 Thunderbird uses C9SZ 13A167 A (2)
The 1970 and later Thunderbirds do not have head lamp covers


Action

______________________________

 

[stovebolt1]

Grrrrrrr..... tried pulling the motor out this morning - I CANNOT get that little pin to disengage from the bracket that holds it to the door. I may need an adult beverage to help calm my nerves, and a cutting torch to facilitate the removal.

 

[Action]

I am not visualizing that.
Mostly because I just removed the single actuator from that Mark IV. (Which sold in a hot minute)
On that ride, there is one of those weird clips holding the actuator motor to the door pivot rod.

Maybe post a picture.

Action

 

[stovebolt1]

I did get the little clip off easily (it's like a wiper arm clip C5ZZ 17531-A), but there doesn't appear to be enough room between the two sides of the door pivot arm to pull the actuator pin all of the way out. According to the shop manual I should be able to get to that pin with the headlamp door closed but, with the door closed there isn't access to the pin from the top. And, with a broken actuator that won't hold vacuum, my little 460 isn't able to generate enough suction to get the door fully closed (or release the tension from the spring in the actuator).

 

[Action]

I remember buying an assembly on ebay. (Usually this happens because it was cheap)
From back in my memory, I believe there is a kind of interlock. Unless the mechanism in in one position (likely closed) the actuator can not be disconnected.
Does the door pivot arm have a cut out section?
A semi-circle missing from the left side of the arm as you are looking at it in the picture.

The springs that pull the covers open can be disconnected. (on one end) This would relieve some tension.

Action

______________________________

 

[Action]

The other PITA way to gain access may be to remove headlights & buckets.
Is the actuator unbolted?
If no, by doing that, there is going to be more movement for the arm coming out of the actuator.

Action

 

[stovebolt1]

I remember buying an assembly on ebay. (Usually this happens because it was cheap)
From back in my memory, I believe there is a kind of interlock. Unless the mechanism in in one position (likely closed) the actuator can not be disconnected.
Does the door pivot arm have a cut out section?
A semi-circle missing from the left side of the arm as you are looking at it in the picture.

The springs that pull the covers open can be disconnected. (on one end) This would relieve some tension.

Action

I would venture that you are correct, there probably is a hole in that pivot arm. Unfortunately with the door closed I cannot find any view down into that assembly to see the pivot arm. Is that spring in the actuator itself? Or off to the side somewhere? I haven't seen a spring within the assembly.

 

[stovebolt1]

The other PITA way to gain access may be to remove headlights & buckets.
Is the actuator unbolted?
If no, by doing that, there is going to be more movement for the arm coming out of the actuator.

Action

I have unbolted the actuator, I was thinking along the same lines that it might offer some additional movement. I'm thinking I'll follow the PITA path and remove as much of the headlight assembly as I feel confident doing. It'll give me a chance to clean up some of the components in there. Sadly it looks fairly complicated and my fear is that I'll get in over my head. No better way to learn though.

 

[Action]

The actuator has no spring.
On Mark IV there are two springs behind each head light assy.

Action

______________________________

 

[stovebolt1]

The actuator has no spring.
On Mark IV there are two springs behind each head light assy.

Action

If the actuator has no spring, what causes the door to close when there is no vacuum? I don't see any other spring in the 71 Mark III parts illustration, and the catalog shows a headlamp cover hinge spring (13A163, section 130, page 16/17) for the Mark IV, but not one for the Mark III. I'll keep looking. I do like the idea of an external spring to ensure the door is open should the actuator/vacuum fail.

Interestingly the actuators I bought from ACP have a caption that indicate that they have a "springless internal diaphragm seal" for more reliable operation.

From what little I've read I assumed that the vacuum port on the top of the actuator was exposed to a vacuum when the light switch was turned off, pulling the diaphragm up, and the connected actuator arm up, causing the door to close. The vacuum port on the bottom of the actuator was exposed to a vacuum when the light switch was turned on, pulling the diaphragm down, and the actuator arm down, causing the door to open. My assumption, perhaps bad, was that the diaphragm contained spring/springs on the upper side of the diaphragm which, in the absence of vacuum, would push the diaphragm down, imitating the presence of vacuum from the bottom port, forcing the door to open.

 

[Action]

There are no springs in or on the actuator that I remember.
The vacuum pulls on either side of the actuator like you wrote about.

The Mark IV has a longer coil wound spring.
I have seen flat wound springs around the shaft for head lamp covers.

And I can not see a spring for Mark III, so maybe there is none.

Action

 

[stovebolt1]

Well, got the darned thing out of there. Had to disconnect the headlamp door hinges and was able to finaggle the dang thing out of its pin hole. Getting the new one in and the door reassembled should be an adventure.

And, yes, the actuator is spring loaded. I'm very curious to see how the new ones operate given that they claim to be springless. Delivery is scheduled for Friday. Given the type of use these old cars will see I'd much prefer that the system relied solely on the vacuum to open the door. It's not that often I'll be running the lights, and if the headlamp door won't open most of us will probably fix the issue before we take her out in the dark.

 

[Action]

OK learned something today.

I am of the opinion that stock is a less expensive way to go for most of everything about classic cars.
That may not be sexy or cool.
Unless the car is pressed into daily service, the standard of well restored stock is acceptable for me.

Dropping most of a grand to make headlamp covers go up and down electrically on a classic ride that is only used when I want to isn't the best use of resources in my opinion. Other disagree and that is OK too.

Sometimes that approach is a PITA and that is the same situation the tech of the 70s faced. I am good with that.

Recommendation, use a treatment for any rubber and plastic pieces.
I use a Maguires leather treatment. And there several other brands with similar products.
Anything plastic, rubber, vinyl and yes leather will benefit from getting a coating of chemical. I use it on interior pieecs AND exterior pieces as well. It is a hard world blowing at the front of any ride at 60 miles an hour. The air blowing at everything has dirt in it and drys out all of the soft parts. A conditioner does a little cleaning and gives some protection. I do this the same way I would wax paint on the shiney side.
Just because it is old tech and old parts doesn't mean I treat the old stuff the same. Assembing dry or untreated

Action

______________________________

 

[stovebolt1]

Agreed. Other than a 57 Chev I did a few years back I've always tried to keep my vehicles as true to original as I could. In this case the extra cost of keeping it original just didn't add up (to me), but like you say - we all place different value on some things. For some strange reason the headlight doors, and the quarter windows, are things I've obsessed about. Maybe because so many Marks I've looked at have not corrected them? Maybe because I think they are the coolest features on the vehicle? But I'm one of those OCD folks that, whenever I pull a part off I'm compelled to clean it, paint it, polish it, do whatever I can to get it back to it's original condition. No one may ever know that the actuator bracket has been treated and painted, but I will. Maybe thats why my first wife left me .

Speaking of which - I hope your better half is doing well and in the fast lane to recoveryville.

 

[Action]

This morning was a good day.
Her condition has improved and it looks like she may get out in the next 24 hours.
Keeping my fingers crossed

Action

 

[stovebolt1]

Well, I got the new actuators installed and..... Snap! The passenger side actuator arm snapped after 5-10 cycles of the headlights. Looking at the area that fractured I can see significant corrosion where the break occurred. Very frustrating. I've initiated a return/repair order with the vendor so we'll see if and/or who steps up to resolve the issue. I'm not sure if it is legit to name specific vendors or mfr's in this forum so I'll not mention who made the actuators or where I got them from.

 

[Action]

was it new?

Action