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Crankshaft Oil Seal Direction?

Discussion in 'Supersport (1974-2007)' started by Samurai, May 23, 2020.

  1. I'm in the process of replacing the clutch and all the seals on the right-hand crankcase cover. Everything was going swimmingly until it came to removing the crankshaft oil seal where it fits into the oil pressure switch housing. The seal was fitted up the opposite way to that I'd have thought correct e.g. with the open face upwards, towards engine, with the washer and circlip above it. To be fair this is the way the Haynes manual shows it, but it made it an absolute pig to remove as there was nothing to get hold of! So much for 'simply lever out with a flat bladed screwdriver' like the manual says!

    Used heat to expand the housing, soak overnight in WD40, careful use of a pick and fine screwdriver, nothing happening :mad:. Long story short, it had to come out as rubber seal part was going hard and was breaking off, so I prised it out as carefully as I could by forcing a jewellers screwdriver between the closed edge and the mating surface all round until I could get some purchase with a larger screwdriver. Made a bit of a mess of the mating surface which under normal circumstances I'd have got a local engineering shop to machine perfectly flat again. Unfortunately, with COVID-19 having closed them, that's not an option at the moment. I'm hoping with careful use of silicon sealer to fill the pockmarks that it won't be too much of a problem as the sidewalls of the chamber are fine. Was there a better way of getting the bloody thing out?

    Ok, finally to my main question (for those that are still awake ;)). Why is the seal up that way in any case? From what I can make out the high pressure feed is coming up the oil gallery from the pump to pressure switch and then into the crankshaft. In that case, it is normal to fit the open end of the seal towards the oil pressure so that it expands the seal and gives, well better sealing properties. I've also tried to fit the loose seal over the end of the crankshaft and due to the angle of the inner seal, it really only wants to fit over it with the closed side towards the engine and not the way it was originally fitted?

    A bit of Googling turned up a post on a US forum asking the same thing, as does a YouTube video. It was mentioned that Ducati reversed the direction of the seal on post 2001 engines, but nobody really knows why?

    So, which way up should I fit the new seal? It does seem to be a slightly different design to the original and I'm wondering if that has some bearing on the reason why it seems to want to fit more easily over the end of the crankshaft in the 'opposite' direction to the original? Does it matter? Who am I to question Ducati's reasoning?

    Here's a pics of the original seal before I removed it and one of each side of the new seal: upload_2020-5-23_18-18-19.jpeg
    #1 Samurai, May 23, 2020
    Last edited: May 23, 2020
  2. If it's the seal that goes here (see above thread) I wish I had not touched it. If the metal bush behind looks ok and you did not chew it up leave well alone. It was a pig to get out, very small shoulder behind it to get hold of. I must admit I did wonder about the direction of seal when I saw it, but sorry, dont have an answer.
    Cheers Gaz
  3. just to confirm, where are you for starters:

  4. Had the same problem with my monster.
    Here’s the pic. As fitted was the other way round and PIA to remove.
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  5. Hi Gaz, yes the bush itself looks Ok, it was the actual ally seat that took a bit of a battering where I'd had to lever the bugger out.

    I thought I'd ask regarding the direction before I the new seal in as it really doesn't seem to want to go over the crankshaft end easily if I try and fit it the same way as the original. The inner lip lets it expand and slip easily over the shaft the otherway round and is clamped there by the spring and why would Ducati change the orientation of the seal after 2001, I can't believe that the oil flow direction changed, but did the design of the seal that you now get? The new one is totally encased in rubber, whereas the original had a bear metal outer face and I'm pretty sure the seal lips looked a bit different?
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  6. Hi Chris, it's seal (9) on the top diagram. I've uploaded some pics to my original post to help.
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  7. as you found, they can be stubborn and bordering on impossible when you have to remove in the "wrong" direction as above, but in future, if you haven't tried this already, a self tapper (or 4!) usually works.
    This video is to the point and gives you an idea, you have to be confident when drilling in preparation, and ready to not go too deep once fully penetrated.

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  8. Hi Chris, that is a good method and I did half consider it. Unfortunately, with the seal fitted as it was, the mating surface would have been directly underneath, so even if I did manage to drill just through the metal edge of the seal, any screw would have gone straight into the mating surface of the case as there is no gap under it. The seal in that vid is up the 'correct' way and therefore has the depth of the seal under it to screw through.

    Love to know how Ducati reckon you should remove it without damage?
  9. Probably with an expanding puller/slide hammer in the bush, using the bush to pull the seal.
    They would expect when you have made the effort to be in there, that you will change everything.
  10. yes, appreciate the depth bit, done this many times over the years but I couldn't remember how much clearance was behind the seal, I will check myself for another time as there must be some gap.. The worst challenge for me is seal exiting in wrong direction, as flange edges often just "dig in" and can result in housing damage regardless of extraction method.
  11. Good point well made! However, having read the thread quoted in Gaz's thread I'm glad I didn't try and do that!
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  12. Unfortunately there is zero gap, the backside of the 'upside-down' fitment is bang up against the seating :(
  13. Yeah, looks like he had fun.
  14. Unless you can find a cross-section view, I still need to look for myself, ;) I haven't had a problem in the past but possibly lucky. Fully encapsulated seals often come out easier, sometimes you wonder how they stayed in on their own for so long.

    EDIT Just seen your added pics, thanks.
    #14 Chris, May 23, 2020
    Last edited: May 23, 2020
  15. Does anyone know the reason why the seal is fitted upside down going 'with' the direction of oil flow instead of 'against' it as would be usual?

    On the US forum, someone did suggest that post 2001 engines had the seal fitted the other way up (don't know if that's true or not) and was wondering if the seal design has changed and replacement ones should be fitted that way too?
  16. I think you might be right, the new seal is fully encapsulated but the old one was a plain metal casing with the rubber bonded to it on the inside, so it fitted flush to the seat and was a really tight fit.

    The fully encapsulated one would perhaps give a screw a little bite but you'd have to be bloomin' careful not to screw into the ally.
  17. The pic I’ve shown is taken from a Ducati service manual for a monster S2R 2006. My monster is a m1000 2004 and was inserted as per your seal. Annoyingly difficult to remove and in the end I used a Dremel with a diamond cutter very carefully reducing the outer ring. When reduced enough and with gentle pressure from the side it collapsed inwards fortunately with no damage to faces. Replaced as per Ducati manual with Flat face facing outward from engine. Basically opposite to how it was fitted.
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  18. that is a very interesting question, and right up my street, and possibly all the petrolhead's streets on here, I could volunteer a few reasons but not the actual answer you are after. Maybe Neil knows this one, for this engine. It would be great to hear the answer from the actual installation engineer from "back in the day", i've had many frustrating cases (NPI) like this in the past, when bordering controversy and never got to hear the definitive answer from the "horses mouth".
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  19. 20200523_194504.jpg
    After removing seal it left mark's on the seal seat / shoulder where screwdriver prized it out. Mechanically I don't think this makes any difference other that it looks a bit rubbish. After that I found a cheapish cover on ebay. This shows seal direct, and what looks like zero clearance behind. If I were to remove seal again i would bend end of screwdriver end to 90 degree and come in parallel to shoulder. Attacking at an angle you are always going to damage shoulder.
    Possibly something like I removed the bush, dremmel the seal walls and cave it in, but it's pretty thin.
    Sorry Geoffduk didn't knick your idea, was replying to thread at the time
    Cheers Gaz
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  20. Well looks like I'll refit the new one the same way although it seems counter intuitive and trust that Ducati have a good reason. Just hope it doesn't leak and I never have to get it out again : unamused:
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