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Thread: How To: ZF 5HP30 control cable plug/gland oil leak - glue fix

  1. #1
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    How To: ZF 5HP30 control cable plug/gland oil leak - glue fix

    I've heard a rumour there's a gluing fix for this oil leak when the plug has deteriorated to the point where it lets the trans oil pass through the plug around the electrical connection pins to the outside. Anyone know where the details of that fix are please? I need them desperately.

    Here's the scene under my 740 today.

    5HP30 pan removed
    Attachment 601511

    Male socket harness termination plug side
    Attachment 601512

    Male socket harness termination valve body side
    Attachment 601513

    Went to ZF this afternoon, showed them the photos and asked for advice. They confirmed it's a very common problem on all gearboxes they see over and over again with no solution. The plastic just goes brittle sitting in hot oil for many years and then starts leaking. They have no workshop solution beyond replacing the entire harness cable. They confirmed there is no source for just the plug alone.

    Zero local stock of ZF part number 1055 227 021 + the earlier superceded part number 1055 227 019 as well. Ex-Germany is all they'll tell me and no idea of a lead-time.

    Solenoid plug connectors at the other end of the harness are all so brittle they can't be flexed without breaking, so removal of the harness from the car is not recommended without a replacement on hand ready to go.

    I really need a patch fix solution here to get the car back on the road. The ZF guys tell me this is an extremely common problem amongst all their gearboxes, not just the 5HP30, so I'm wondering if someone in here has done this before and knows what to do or can at least point me in the right direction?

    Thanks
    Attached Images Attached Images

  2. #2
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    I have seen once photos - but cannot remember where - where someone sealed the complete plug side inside the transmission (coming from the valve body) with a kind of liquid epoxy resin = into the back of the plug side with wires + pins in
    place. Did not look professional, but apparently worked.
    A new valve body wire loom you can get cheaper in the U.S., for example here for $135 +shipping http://www.thectsc.com/catalog/5hp30-6.html
    As for the 'glue' I have no idea, you have to find something which is oil/ATF resistant and temperature resistant , call the the makers.
    Solenoid plug connectors usually break, my buddy who makes the trans service just cleans up the broken plastic parts and tells me no problem without that missing plastic.
    Shogun tricks and tips for the E32 series are HERE!

  3. #3
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    are slow
    Permatex Right Stuff or something similar?

    Will be a pain to get it off.

  4. #4
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    OK, here's what I did with photos to illustrate. Got the least viscous, long pot-life epoxy resin available applied directly down into the pin sockets with a hypodermic syringe from the local chemist. Then with the sockets filled, we made a collar dam around the location flange out of plasticine (could use anything similar like blu-tack) to block off the four slot holes in the perimeter of the plug collar which are there for no easily apparent reason. With the holes blocked off to retain the resin in the pocket to be filled around the wires we then cut the needle off the syringe and filled the rest of the surrounding void with resin to completely fill and seal the whole area to the wire insulation.

    Obviously there's a lot of cleaning & degreasing required before you go anywhere near the resin. I used lots of brake cleaner, high pressure air, grease & wax remover and finally I used acetone to lightly etch and dissolve the wire insulation making it tacky/sticky to give the resin something to mechanically key with.

    Before any resin with plug set up in hole in workbench with bundling collars cut to allow separation of wires for access with syringe needle.
    Attachment 601996

    Filled with wet, liquid resin with plasticine dam in place around collar under workbench to prevent resin running away through moulding slots.
    Attachment 601997

    End result with resin set rock hard after 24hrs sitting. No shrinkage and set rock solid. Plasticine dam now removed, moulding slots completely blocked with solid resin.
    Attachment 601998 Attachment 601999

    Here's a photo of the back side with the plug end that extends outside the gearbox to connect to the DME control cable. Here you can see one of the moulding slots in the collar of the plug body that needs to be dammed up with some putty type stuff that won't adhere easily to epoxy resin.
    Attachment 602002

    I have no idea what the slots are for. Maybe they're just part of the plastic moulding process required to make the plug in the first place or perhaps they're required for some reason to allow ATF to splash lubricate the two replaceable O-rings that seal the plug to the hole in the gearbox valve body in which it mounts? I really don't know but they definitely make sealing up the plug harder than it needs to be. With the slots open, you're relying totally on the integrity of the O-rings to hold the oil in the gearbox much more than you are with the slots blocked. The slots provide free passage of oil straight through the plug collar to the O-rings. With the slots blocked, the only oil that will come into contact with the O-rings will be any leakage around the collar and the shoulder of the gearbox flange into which it mounts. If anyone else doing this sees a problem with this and wants to maintain the open slots, then I suggest first blocking them up completely like here and then redrilling passages through the resin blocks to recreate a direct oil path to the O-rings again.

    Personally, I think this looks so much better than the original plug that I'd do the same again to a brand new harness before installation if I had to. I will be absolutely amazed if I have any ATF leak problems from this plug again!
    Attached Images Attached Images

  5. #5
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    I wouldn't use resin around the wires. Epoxy resin no way. Cant be removed and potentially problematic to work with in tight spaces. Silicone high temperature sealant will do, pretty tough when fully cured, and it is removable without damaging anything else if you ever need to get at the wires for any reason. And you just need to let it set for like 60 minutes before reinstallation, but full strength happens after 24 hours. I've used silicone sealant on the wire spades under my relays which were coming loose, and it has not caused any problems in the last 6 years.And this is not gasket sealant. Its the high temp silicone sealant that feels like hard rubber when dry, good to 450 or 500 degrees can't remember.

    Well it shouldn't be too difficult to do if you ever have a leak, just pull the socket out an inch and wind some tape around it. Or you could always apply a small bead of the same sealant I was talking about from the outside, just like what this guy did here for a hg mating surface
    https://www.bimmerforums.com/forum/s...#post29732531:
    Did you consider using clay mix epoxy to plug up the plug? That would be much faster, and equally good if it would work and when soft it can be easily stuffed into the plug around the wires with a thin stick, no need to plug holes on the other side temporarily. Don't get me wrong now. Using resin is a great idea. But would using clay epoxy mix be even better?
    Last edited by shogun; 06-11-2017 at 12:36 AM.

  6. #6
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    Quote Originally Posted by flying525 View Post
    I wouldn't use resin around the wires. Epoxy resin no way. Cant be removed and potentially problematic to work with in tight spaces.
    Not being able to be removed was the whole point. I'm fully aware that this is a very permanent fix. That's exactly how it's intended to be. If the cable or the wires ever fail again, then it will require the purchase of a whole new harness to repair in most likelihood. Anything less than a permanent solution opens the door to fragments of silicon or whatever else you try to seal it with, breaking off or falling off the plug and circulating through the valve body with the oil. That scenario will have far more expensive and permanent ramifications than needing to buy a new plug harness!! Epoxy resin will not without considerable mechanical attack ever part company with what it's bonded too. This is a very important consideration when its installed inside an automatic transmission valve body. In any case, the wire pins cannot be serviced or detached from the plug even before being filled with epoxy resin. They are moulded into the plastic of the ABS plug in the manufacture. They have to be because they need to form an oil tight sealing interface between the metal pins and the plastic plug to stop ATF leaking out. This is why ZF can't sell you just the replacement plug alone. There's no way to insert the pins into a new plug. They have to be moulded into it during the manufacture of the complete harness.

    Quote Originally Posted by flying525 View Post
    Silicone high temperature sealant will do, pretty tough when fully cured, and it is removable without damaging anything else if you ever need to get at the wires for any reason. And you just need to let it set for like 60 minutes before reinstallation, but full strength happens after 24 hours. I've used silicone sealant on the wire spades under my relays which were coming loose, and it has not caused any problems in the last 6 years.
    Are these relays constantly flooded in hot ATF oil and situated right next to a valve body with a maze of channels that looks like this, fed by solenoids controlling pin hole sized valves supplying the oil to open and close the clutch packs?
    Attachment 602008
    If not, then I think you might be slightly underestimating the consequences of getting the sealant wrong when working on the inside of an auto valve body.

    Quote Originally Posted by flying525 View Post
    And this is not gasket sealant. Its the high temp silicone sealant that feels like hard rubber when dry, good to 450 or 500 degrees can't remember.
    Yeah, I wasn't going for hard rubber consistency. Rubber goes soft in oil and deteriorates and then falls apart. I was going for hard as granite and completely impervious.
    Attached Images Attached Images

  7. #7
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    Quote Originally Posted by flying525 View Post
    You might still have leaks if you did not use a new o ring
    Yeah dude, of course I've got new O-rings to go in. That was the whole start of this exercise in the first place. There was an oil leak at the plug, so I bought the O-rings for pennies. They were a grand total of $5 each. If $10 worth of O-rings had solved my auto trans oil leak problem then I would have considered myself very lucky indeed. Sadly, upon removing the plug it was determined that it was actually leaking through the electrical pin connectors instead of (or perhaps in addition to) past the O-rings. That was where the epoxy-fill solution came in since a new cable was approximately 4 weeks ETA lead-time ex-ZF Germany.

    The old O-rings can be seen lying in the cardboard box in the above photos. They have been cut here because I was using them as reinforcement for holding the plasticine dam in place around the collar of the plug. When the resin had set I just sliced them with a knife to remove the plasticine dam easily without disrupting anything else. They were not going to be reused anyway since I have new ones ready to go in.

    The old O-rings had no elasticity left in them after 25 years. They would stretch open but not spring back again. Completely knackered. New ones are super-tight and I'm told are a very tight fit requiring quite a bit of lubrication to get the plug back into the flange in the valve body.

  8. #8
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    Quote Originally Posted by flying525 View Post
    Did you consider using clay mix epoxy to plug up the plug? That would be much faster, and equally good if it would work and when soft it can be easily stuffed into the plug around the wires with a thin stick, no need to plug holes on the other side temporarily. Don't get me wrong now. Using resin is a great idea. But would using clay epoxy mix be even better?
    I'm afraid I'm not familiar with what clay mix epoxy is but I assume some kind of an epoxy putty or filler used in external wood work repair for things like dry rot? I did not consider using that, no. What we had our minds set on was something as liquid as possible that could be squeezed through a syringe and with as long a pot life as possible without going stupidly light on the hardener. Of concern also was to ensure that epoxy is not electrically conductive. Apparently some types of epoxy are infused with silver + nickel particles to make them conductive, but the one we used was not this kind.

    Whilst avoiding having to dam up the slots would seem an easier method, it's really not that much extra effort to block the holes and you are definitely going to get a better penetration and more complete air bubble free filling with a properly liquid mix than with a putty. The gaps around the wire pin sockets are extremely small. They may look big enough to poke a stick with in my very close range macro photographs, but trust me, they're not. We used a hypodermic needle so fine, I could barely even see it without the use of a magnifying glass.

    Attachment 602051
    Attached Images Attached Images

  9. #9
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    Thumbs up How To: ZF 5HP30 control cable plug/gland oil leak - glue fix

    Good afternoon fellow enthusiast.

    I'd like to share my experience in my transfailsafe code solution.

    About a year ago I started getting failsafe codes when driving the vehicle hard. I briefly looked into the issue but didn't devote enough time to it, had it looked at by two "BMW specialist" mechanics specifically to diagnose the issue. Both said with 100% certainty that the transmission needed a full rebuild.

    I decided to do more work on my end and followed Timms advice on meeknet to fix the issue.

    Like him my issue came from the switch on the side of the gearbox, however it was not an issue of dirty contacts. It was an issue of rubbed off insulation and shorted wires inside of the black sleeve.
    Attachment 700993Attachment 700994Attachment 700995

    I cut and soldered in new wire and taped up where there was not enough wire, and so far its run perfectly.
    Big thanks to Timm for all his work on Meeknet.
    ~ AMurph ~
    ~Nor Cal E31 Owner~

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