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Discussion Starter · #1 ·
Since I bought my 15K mile LX last year, the power seats on both sides, primarily front to back, barely work. The only way to get the front to back to work, and that only happens when you have the seat height almost all the way up, is to get the height right, then it will move forward and backwards, that is until it gets to a point, then it grinds to a halt. If you wait a minute or so and try again, it will move a bit, rinse and repeat. The passenger side does the same thing.

So, today I decided to see what I could do. I took out both seats and started with the driver side. I flipped it over and proceeded to take the motors out. When I did this, what immediately jumped out at me was the condition of the rotors (commutator) where the brushes make contact..Looks very nasty, like grease or something got into it.



So I cleaned all three of them up and used very fine (400 grit) sand paper to freshen up the surface.



I also found that same goop on the brushes



I cleaned up the brushes as well, which really didn't look too bad.. Here is the after pic..



So, after all of this, and lubing the tracks, front to back, the problem was only marginally better, and by that, I mean barely. I thought I would have better luck on the passenger side, so I took it all apart, to find it a lot cleaner, no grease buildup or anything. The rotor surfaces (commutator) where the brushes touch were not as bad as the other, but still had some buildup.

I cleaned all of this up, but during reassembly, I dropped the brush holder and one of the stupid bushings escaped. I think I heard it actually say "Wheeeeeee, I am free!!!!!" when I dropped it as I could not find it after that! Maybe tomorrow.

In an attempt to maybe get the passenger seat back in the car tonight, I went to my 95 SC seats, the driver side, which are in my carport. I wanted to take the motors out and put them in the passenger seat. Well, this proved to be and exercise in futility!! After all of the cleaning of the SC motors, I find that they are different, ever so slightly. It seems that the shaft is slightly larger on the 95 SC, or maybe in the 95's in general, for the rotors.

Anyway, after all of this, I am still stumped as to why these motors have issues. They are so basic, and I can assume that at some point, they worked ok. I did notice something that may cause the weakness in these motors...The brushes... I didn't get a pic, but noticed on my driver seat that the brushes were not contacting the commutator very well. I would say that only about 60 percent of the brush surface was actually making contact with the commutator. Could this be a part of the problem? If the brush is not making full contact, could it cause the loss of power and torque in the seats?

I may, in the coming weeks, actually take apart the gearbox assembly to see if there is a problem in there... If Ford used the same practices on the seat motors as they did in their power windows motors, plastic gears and such could be disintegrated in the gear box. I wouldn't put it past them...

Any thoughts, theories or other comments are welcome!

Thanks,
Phil
 

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1994 Cougar XR7 DOHC/5-Speed
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My seat problems typically pinpoint to the gearboxes, and no ford did the opposite and used STEEL worm gears inside a plastic case. Typically the case cracks and the worm gear ends up skipping on the driven gear on the forward/back movement.

That's a crazy amount of brush/commutator wear on yours, the ones I pulled with my SC seats had gummed up tracks and cracked gearboxes by those looked brand new.
 

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1991 Mercury Cougar LS 5.0 in restoration
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What about doing a comparison of the motors out of the tracks? Then you can compare sound/speed of the motors unloaded. I've never done this, just an idea.

Are the SC seats spares, or you have an SC you took them out of? If spares, swap the track/motors.

Did you check voltage?
 

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Man; it's the 30 yo grease. clean all that **** out, and relube it, and all is good.
 

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Discussion Starter · #5 ·
What about doing a comparison of the motors out of the tracks? Then you can compare sound/speed of the motors unloaded. I've never done this, just an idea.

Are the SC seats spares, or you have an SC you took them out of? If spares, swap the track/motors.

Did you check voltage?
The seats from the SC are spares. I would love to use them in my LX as I think the LX seats just suck, no support, uncomfortable, especially if you can't adjust anything. They need new covers as the existing SC ones are red, and my interior is tan.

Testing them unloaded would require complete removal of the entire motor / gearbox assembly as the bushings are in the gearbox for the rotor. Luckily, the passenger side SC seat has a manual track, so, one less to worry about. :)

I was thinking about moving the motor pack from the SC seats, but now I know that this will not work as I am pretty sure the shaft size is different between the 94 and 95's, or at least that is my observation. You can actually see the differences on the shaft here...95 SC motors on the left, 94 LX motors on the right...

 

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Discussion Starter · #6 ·
Man; it's the 30 yo grease. clean all that **** out, and relube it, and all is good.
Are you talking about the grease in the gearbox? The rails were almost dry, but I did grease them up on the drivers side, cycling it forward and back, as much as I could, but it still didn't help. Maybe if I could get in the gearbox...I wonder if movement from front to back requires all three motors?
 

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Discussion Starter · #7 ·
My seat problems typically pinpoint to the gearboxes, and no ford did the opposite and used STEEL worm gears inside a plastic case. Typically the case cracks and the worm gear ends up skipping on the driven gear on the forward/back movement.

That's a crazy amount of brush/commutator wear on yours, the ones I pulled with my SC seats had gummed up tracks and cracked gearboxes by those looked brand new.
I think that brush / commutator in the pic isn't a great representation. It was just grease or something on it. It cleaned up easily.
 

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1994 Cougar XR7 DOHC/5-Speed
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Are you talking about the grease in the gearbox? The rails were almost dry, but I did grease them up on the drivers side, cycling it forward and back, as much as I could, but it still didn't help. Maybe if I could get in the gearbox...I wonder if movement from front to back requires all three motors?
Only one motor is responsible for front to back movement(think its the middle but I'm not certain in my recollection), the other two are for up and down and tilt (pulling or down up on the main switch operates both motors, the tilt switches operate each height motor individually)
 

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Only one motor is responsible for front to back movement(think its the middle but I'm not certain in my recollection), the other two are for up and down and tilt (pulling or down up on the main switch operates both motors, the tilt switches operate each height motor individually)

Yes the middle motor is front to back on my 97th anny seats (same as the sc). I just took mine all apart to blast and repaint the rails that mount to the floor.
 

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To fix those seats, you have to disassemble, clean the dried grease out, and apply new grease. They'll work like new.
Do the seat tilt mechanism while you're at it. And the door lock mechanism...
 

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Discussion Starter · #11 ·
My seat problems typically pinpoint to the gearboxes, and no ford did the opposite and used STEEL worm gears inside a plastic case. Typically the case cracks and the worm gear ends up skipping on the driven gear on the forward/back movement.

That's a crazy amount of brush/commutator wear on yours, the ones I pulled with my SC seats had gummed up tracks and cracked gearboxes by those looked brand new.
I did a little test tonight on my passenger seat track with the motors out. I took the drive shaft out of the middle spot and put it in my drill and rotated the gear box using the drill. The track moves front to back until a certain point where it stopped and the case came open revealing the weak spot.
My seat problems typically pinpoint to the gearboxes, and no ford did the opposite and used STEEL worm gears inside a plastic case. Typically the case cracks and the worm gear ends up skipping on the driven gear on the forward/back movement.

That's a crazy amount of brush/commutator wear on yours, the ones I pulled with my SC seats had gummed up tracks and cracked gearboxes by those looked brand new.
I saw what you mean last night! I too one of the driveshafts from the three motors and put it in a drill last night and turned the middle (front to back) location with it. it went so far then came to a sudden stop and that is where I saw the casing for the gear box separate with a clunk sound at the same time. Would it be safe to say that what happens is the motor take the rail so far and then binds on something. When this happens, the motor is still pushing along, but since it cannot move, the worm gear over torques the gear box housing and the case gives? Do you recon a full disassembly, cleaning and some kind of repair to the case would fix it without having to buy another complete track/motor assembly?

Thanks
 

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1994 Cougar XR7 DOHC/5-Speed
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It's probable there's some dried and gummed up grease or something like a coin that got into the track causing a hard stop, sometimes the tracks themselves can be a little wavy too for whatever reason, it's all pretty fixable with some elbow grease. The gearbox case is trickier, I tried repairing mine with epoxy and some steel to try encasing the cracked area but it didnt work long, I just ended up salvaging one off another set of seats I had
 

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Discussion Starter · #13 ·
Well, I stripped down my passenger side seat track after swapping a manual track onto it. That was not fun, but I got it apart. I pulled the gearbox out (which cracked a started to separate on the top where the front-back worm gear is. I drilled out all of the rivets and took it apart. I could find nothing wrong on the inside of it. Ford used TONS of that white grease on the inside of it. I forgot to mention that I did test it before pulling the gearbox apart, and everything turned without resistance with the gearbox off the track, so, likely, the track is binding bigtime. That is next to look at today. The inside of the gearbox looks ok. All of the gears are metal and they look fine. So I don't think the gearbox is the issue for us.

My guess is, if there is damage to the gearbox, like the casing splits, that this is caused by the track binding and the motor and gears over-torqueing the case.

On my searches online, I did find something interesting. Apparently Ford also used these same gearboxes and motor assemblies on several other Ford's for quite a while. In fact, the 94ish Taurus / Sable seat track is almost identical save for some small differences. But, the motor packs look identical.
 

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Discussion Starter · #14 ·
Ok, another update...for anyone who is interested. Over the weekend, I disassembled the seat track from my passenger side. What a PITA, but, the findings were well worth it. Once I got both rails independent of each other, I found that the only way the plastic inner slide would move in the steel rail was if I used a hammer to move it. I was finally able to separate the slides from the rails. I used a round wire wheel on a drill to clean the inside of the rails (steel part). There was some rust, but not a ton, but these things were BONE DRY, no lube at all!! Once apart and cleaned, I reinstalled the rail into the slides on both sides and was now able to move them both freely (still some resistance because I think that this is just how they are designed) by hand where before, this was impossible. Also forgot to mention that before I started hammering them apart, I actually had to use penetrating oil just to get them to move.

I am guessing I will find the same issue on the drivers seat when. I think I am just going to pull the tracks from my SC seats and pull them completely apart and clean / lubricate everything. The move now, but just slow. I am also gonna say that this is what causes the gearbox casings to crack due to too much power and torque being applied to almost frozen tracks, something has got to give!

I honestly believe that fully disassembling these seats, like mentioned above, cleaning and the heavily lubricating the slides will make a world of difference in the function. Why Ford didn't think much about putting a very good lube on these, I have no clue. Not sure how the rust arrived either, unless someone spilled a drink or lived in a very humid climate. I think applying liberal amount of a medium synthetic grease will go a long way and restore full function.
 

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1994 Black T-Bird 4.6 DOHC TR-3650
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Ok, another update...for anyone who is interested. Over the weekend, I disassembled the seat track from my passenger side. What a PITA, but, the findings were well worth it. Once I got both rails independent of each other, I found that the only way the plastic inner slide would move in the steel rail was if I used a hammer to move it. I was finally able to separate the slides from the rails. I used a round wire wheel on a drill to clean the inside of the rails (steel part). There was some rust, but not a ton, but these things were BONE DRY, no lube at all!! Once apart and cleaned, I reinstalled the rail into the slides on both sides and was now able to move them both freely (still some resistance because I think that this is just how they are designed) by hand where before, this was impossible. Also forgot to mention that before I started hammering them apart, I actually had to use penetrating oil just to get them to move.

I am guessing I will find the same issue on the drivers seat when. I think I am just going to pull the tracks from my SC seats and pull them completely apart and clean / lubricate everything. The move now, but just slow. I am also gonna say that this is what causes the gearbox casings to crack due to too much power and torque being applied to almost frozen tracks, something has got to give!

I honestly believe that fully disassembling these seats, like mentioned above, cleaning and the heavily lubricating the slides will make a world of difference in the function. Why Ford didn't think much about putting a very good lube on these, I have no clue. Not sure how the rust arrived either, unless someone spilled a drink or lived in a very humid climate. I think applying liberal amount of a medium synthetic grease will go a long way and restore full function.

It is what I'm doing right now. And yes, after disassembling each tracks, removing rust and everything, applying lithium white grease into the tracks, they will slide with a little resistance and will not get stuck anymore. BTW, if you think about replacing your power seat units, 97-98 Mark VIII's had a stronger design for the drive assy. and are fully compatible. 🔧
 

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Discussion Starter · #17 ·
It is what I'm doing right now. And yes, after disassembling each tracks, removing rust and everything, applying lithium white grease into the tracks, they will slide with a little resistance and will not get stuck anymore. BTW, if you think about replacing your power seat units, 97-98 Mark VIII's had a stronger design for the drive assy. and are fully compatible. 🔧
Thanks for the tip! As for the MK VIII, are you talking about just the motors or the whole seat track?

Thanks
 

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1994 Black T-Bird 4.6 DOHC TR-3650
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The motors have bigger bushings, the gearbox has bigger exterior drive gears (8 theet instead of 6 for earlier T-Birds or Cougars). Later MN12's have 8 as well, so you can mix-up every tracks that came with a 8 theet gearbox if you want to change a rusted track. The seat back from a Mark VIII use a pivot bolt on one side, while T-Birds and Cougars don't, but it is not a problem.
You can also use a Mark VIII passenger seat with the electronic control under it, and install your seat and seat back on it. Since it is an independant system, it is compatible with your car, and it gives autoglide seat and power recliner. You just need to connect the right wires from the control unit to the power source of your T-Bird. I can show you the wires to connect, if you decide to do that.
For the driver seat, the Mark VIII electronic control system is not compatible. However, a passenger side control unit can be used with a Mark VIII power seat and power recliner unit (driver side), to have the same functions for both seats. If you have time to spend and a garage to work, it can be done
 

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Discussion Starter · #19 · (Edited)
The motors have bigger bushings, the gearbox has bigger exterior drive gears (8 theet instead of 6 for earlier T-Birds or Cougars). Later MN12's have 8 as well, so you can mix-up every tracks that came with a 8 theet gearbox if you want to change a rusted track. The seat back from a Mark VIII use a pivot bolt on one side, while T-Birds and Cougars don't, but it is not a problem.
You can also use a Mark VIII passenger seat with the electronic control under it, and install your seat and seat back on it. Since it is an independant system, it is compatible with your car, and it gives autoglide seat and power recliner. You just need to connect the right wires from the control unit to the power source of your T-Bird. I can show you the wires to connect, if you decide to do that.
For the driver seat, the Mark VIII electronic control system is not compatible. However, a passenger side control unit can be used with a Mark VIII power seat and power recliner unit (driver side), to have the same functions for both seats. If you have time to spend and a garage to work, it can be done
So I could use the 97-98 Mark VIII seat track and just install my entire SC or LX seat bottom and and backs on them? Sorry if this sounds like s dumb question... I would like to retain my Tbird seat controls and Tbird look. Will the Tbird trim covers fit the Mark seats?

Thanks,
 

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1994 Black T-Bird 4.6 DOHC TR-3650
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There are no dumb questions, I am happy to answer you. The 97-98 Mark VIII power seat units are compatible for floor bolts holes, and SC or LX seats. IF you want to keep your car look original, you have to remove the electronic control stuff and connect your seat connector to the 3 motors, like in your car. You can install your seat back with manual recliner directly on it, like in your T-Bird. There is a welded nut on the inside side instead of a hole, but you should be fine.
 
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