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  1. #1
    FEP Power Member 85stanggt's Avatar
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    Default Convertible Top Motor Slowly Seeping

    Not sure if I'm posting this in the right place.

    My convertible top motor started leaking about 10 years ago. I took it to a local rebuilder and they replaced some seals inside. It seemed to still slowly seep so they did it again and then things seemed ok...

    I recently removed the rear seat to find that the slow seeping has continued and left a sheen of fluid on the sheet metal behind the rear seat back and kind of made a mess at the base.

    I don't think it's an inside seal, though because it seems to have fluid building up around the middle of the motor -- where the reservoir meets the motor body. There looks to be a large o-ring that seals the two pieces together. At the end of the reservoir is a large, weird, 3-sided screw head.

    Is this the head of a large screw that runs the length of the reservoir and screws into the motor body to squeeze and seal the two pieces together against the o-ring? Has anyone taken one of these apart and can shed some light on how this thing works? Don't want to screw mine up trying to tighten the wrong thing.
    1985 Mustang GT Convertible
    Stock and original @ 213k, except for dynomax ultraflos.

  2. #2

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    Have replaced a couple of pumps on 1970 thru 1987 Mustangs. Cost of the pump new is about $245 Needs to have ATF fluid only on refill and only to bottom of the drain.

    You are correct that the large screw runs the length of the reservior and seals the two pieces with an 0-ring. If you were seeping before, you could have a corroded lid on the reservior tank, a damaged o-ring, or a damaged surface on the motor base. Might be able to seal it with some sealant, in my case I just didn't want the hassle of another leak and just replaced the pump. Since the vehicle is over 30 years old, it was also just easier to replace the pump and new hydraulic lines. I had to replace the one in the 1970 Mustang because I had a very leaky ram, which was probably caused by the years and corrosion.
    Last edited by 20thAnn; 05-23-2018 at 12:23 AM. Reason: Additional information

  3. #3
    FEP Super Member webestang's Avatar
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    Default

    I'm going to use this kit when my starts to leak....I don't trust rebuilding an old pump.
    https://lmr.com/item/LRS-53300K/83-9...-Top-Motor-Kit

    Scotty
    1985 Fox Notch 4-banger Ranger tube header Eastwood Royal Blue
    1988 Fox LX 5.0 AOD Vert BBK 170mph speedo Candy Apple Red
    1999 Mustang Coupe V6 Auto Chrome Yellow -Daily Driver.
    Past Pony's.....
    68 Coupe Inline-6 3-Speed-Man. Primer
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  4. #4
    FEP Power Member 85stanggt's Avatar
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    Default

    Well, the pump works fine. It just must be seeping a very little amount because I haven't touched it in 10 years. And its not like there was a puddle or anything just an oily film.

    What socket fits that large bolt? I'd like to start by feeling how tight it is. Then I can just take it apart if need be and clean things up and re-seal it. But I'd rather not have to remove it...
    1985 Mustang GT Convertible
    Stock and original @ 213k, except for dynomax ultraflos.

  5. #5
    FEP Super Member gr79's Avatar
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    Sure miss a 'verti every now and then.
    Once, kept the top down for 2 weeks straight on my '67 Mustang.

  6. #6
    FEP Power Member 85stanggt's Avatar
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    Can get away with that down here in FL in the winter. Surely not the summer though!
    1985 Mustang GT Convertible
    Stock and original @ 213k, except for dynomax ultraflos.

  7. #7
    FEP Power Member 85stanggt's Avatar
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    Ok just wanted to update this thread and make everyone aware that these pumps are extremely simple and easy to rebuild. It turns out that my motor was not leaking from the reservoir o-ring, but rather from the pump shaft seal o-ring, as there was a drip of ATF hanging on the back of the motor where the wires run out.

    I called around near me, and the only person who could "rebuild" it was 45 minutes away and wanted $125 to do it. Then I found a thread online from a ~1960s era car with a very very similar pump with pictures of taking it apart, cleaning and rebuilding it. So I figured I would do the same.

    The following is a series of pictures that shows how these come apart and go back together. Anyone can do this if there's a leak, so long as the pump is making good pressure, which means things aren't too worn. There are only 5 o-rings that seal this entire pump: one on the end of the reservoir bolt, the reservoir o-ring itself, 2 o-rings for the hydraulic lines, and 1 o-ring for the pump shaft. I only replaced my pump shaft seal with a Viton o-ring from my Harbor Freight o-ring assortment, but NPD actually sells a complete rebuild kit for these motors for $30.

    If your motor leaks through the pump shaft seal, it is a good idea to fully disassemble everything, including motor armature, brushes, etc (pretty easy). You will see in the picture below how gunked up everything was. Take a look at the brushes also, because if they are too worn, now is an easy time to replaced them by soldering in some new ones (I didn't need to).

    Here is the reservoir removed. An 11/16" socket fits tightly over the end to loosen it.


    Once the reservoir is off, you see the front plate of the motor. There are 5 bolts that hold it on. Loosen these and the plate comes off. Remove the plate with the MOTOR FACING DOWN, as there are two ball bearings set in the plate to control the fluid flow (see pic #3).


    Here is the back of that plate with the two balls in it:


    And here is under that plate. You can see the pump shaft there inside that star piece, which is inside another outer ring. That ring is very very precisely machined to fit inside the pump face. Under these two pieces is the shaft o-ring, so remove these two pieces but be careful not to score anything.


    Here's the pump shaft with the o-ring:



    Now, on the back of the motor are two screws. These run the length of the motor and screw into the back of the front plate in the above picture. Once these screws are out, you can hold the back plate on if you don't want to disassemble the motor and just pull the front plate off while holding the pump shaft in place. That'll get the front plate off and let you get the o-ring out without having to scratch at things to pick it out. If you pull the back plate off, the brushes are in there with the springs and the ball bearing for the base of the motor.


    Reassembly of the brushes is hard without a second person, since you have to hold the brushes in against the spring pressure while reassembling the motor. Also, don't forget the ball bearing in there and a bit of grease for it. I used compressed air to try to blow all the residual fluid out and then used paper towels and a tweezer to clean up the rest. I think the fluid causes excess wear of the brushes if it's in there, so best to clean everything out.

    That's it! Pretty simple little device all in all. No one should be afraid to take this apart, and no one should pay upwards of $100 for someone to replace an o-ring.
    1985 Mustang GT Convertible
    Stock and original @ 213k, except for dynomax ultraflos.

  8. #8
    FEP Super Member gr79's Avatar
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    Default

    Nice write up. No verti here any more, but enjoy the read.
    An electronic contact cleaner, safe for plastics, would clean that right up.

    Always good to know the top will work when that sudden summer cloudburst happens.
    Seen a mint old car get drenched at a show because the top would not go up.
    Cats and dogs. Big time. Buckets. Like a auto car wash. Lasted half an hour.
    "Well it was never driven in the rain...."

  9. #9
    FEP Power Member 85stanggt's Avatar
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    Haha my dad has some stories with this car... Like one time in the grocery store when they came on over the PA system, "to the owner of the gray Mustang convertible with the top down -- it's pouring outside." Of course Florida rain means buckets, so when my dad ran outside, the car was soaked including a pond of water in the center console. That was way back when probably when the car was still pretty new.

    I got caught in super heavy rain driving one night. I can usually scoot through since the water pretty much blows right over the interior at speed. But this again is FL rain, so it started normal and changed to buckets. So much that it collected at the top of the windshield and was pouring over like a waterfall. That's when stopping became a necessity.

    Man, great idea with the contact cleaner! I have it and didn't even think. That would have done a great job...

    The motor purrs so quiet now and runs like twice as fast some how. The top flies up and down. 2 days so far and no leak. Fingers crossed.
    1985 Mustang GT Convertible
    Stock and original @ 213k, except for dynomax ultraflos.

  10. #10
    FEP Super Member gr79's Avatar
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    Haha waterfall.
    Started carrying towels in every car since owning a convertible.
    Did not have power windows or a/c.
    Would have to stop and scramble to roll up windows.
    Worse was when the boot cover was on and forgot it was.
    Kept a lot of debris out but did not have a set pattern to use it.
    Usually not. Did not like to park and shop with top down.

    A pen oiler would be good for lubing the top frame pivot points and latches.
    Sprays are messy.

    People throw stuff in an open car and pickup beds.
    Open top good for hauling big items.
    Seen a top down car once full of undelivered news print.
    Not mine. Someone dumped them in. Rolled up kind with rubber band.

    One time waiting in line at a .25 car wash.
    Did see an older nut power washing the interior of his verti Chrysler boat.
    Inside w/s glass, dash, and all.

    Plastic rear windows.
    Another item to zip up. Think they had to be unzipped before lowering top.
    Or they eventually got messed up.

    Had the latest and greatest optional two piece glass rear window.
    Which had a silicone like rubber hinge that started to split.
    Did not need to be opened to lower top.
    Was airy in there with it down, top up, windows down.
    Like on a hot sunny day. Top up for shade.

    Thing was a party car. Everyone had fun in it. Me- always had to drive.
    Even without console, 6 young adults was a tight fit.
    Only girl/boy seating allowed. No segregation. All squeeze in together or stay home.

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