Kevin.payne.15 Posted May 8, 2018 Report Share Posted May 8, 2018 All. Has anyone else experienced a leaking oil seal from the overdrive to the speedo cable? Ive just had my dials restored by speedy cables who advised me that the speedo was contaminated with gear oil and they suspected a leaking oil seal at the gearbox (d type overdrive for me ) i looked this weekend and unfortunately it looks like they might be correct. I’ve removed the angle drive but the main unit is stuck. I think I need to also remove exhaust pipe to access the locking bolt at the end of the overdrive - is this correct? when I looked at the Canley web site I think the oil seals are not serviceable unless I have the wrong parts. There is one o ring but that doesn’t appear to be near the rotating shaft. Also the main unit ( the bit that actually goes into the overdrive) has a couple of flats that suggest it should be screwed in but isn’t tight and actually rocks back and forth a few degrees. Overall not encouraging. Has anyone else explored.? Do I bother? Can you get seals? How do I remove with gearbox still in car but cover removed. I’m sure someone out there has beaten me to this problem thanks in advance kevin Link to comment Share on other sites More sharing options...
Pete Lewis Posted May 9, 2018 Report Share Posted May 9, 2018 There are two seals on the drive the 0 ring seals the hsg. To the case , Yes retained by the short spigot bolt in the rear hsg. Yes it just pulls out The end of the body has the screwed in speedo cable adaptor , hence the two flats this is screwed in remove and under is a small oil seal If not on normal suppliers try od spares or overdrive repairs for spares both very helpfull Should be able to do this On car, maybe undo the mount and lift the rear of the box if access is tight Dry thr speedo inner and lubticate with graphite powder or non transitional grease Always fit a 7/16" washer insde the angle drive , to space it away from the od drive Pete Link to comment Share on other sites More sharing options...
hugh Posted May 9, 2018 Report Share Posted May 9, 2018 Other reason for this is a blocked gearbox breather, causing the box to pressurise (slightly) when hot this then pushes oil up the speedo cable (pipe) Link to comment Share on other sites More sharing options...
DanMi Posted May 9, 2018 Report Share Posted May 9, 2018 speedo seal is available 50607s on here https://rimmerbros.com/Item--i-GRID005716 you need to remove the bolt that holds the unit in and then pull it out, drain oil first of course. The bearing should just unscrew to replace the seal however on some later models they are pinned which is a right PITA to drill out. The whole bearing assembly and gear drive if needed are available from the specialist Pete mentioned. Link to comment Share on other sites More sharing options...
Pete Lewis Posted May 9, 2018 Report Share Posted May 9, 2018 well done Dave , i had forgotten about the ones with a roll pin but think that only need to be removed to change the pinion that would help in digging the old seal out . Pete Link to comment Share on other sites More sharing options...
Kevin.payne.15 Posted May 10, 2018 Author Report Share Posted May 10, 2018 Ok thanks. Where is the breather please. I’ve looked but haven’t found. Also. I’ve looked on the rimmer site for the d type overdrive which is on the spitfire site not GT6 one and yes they have seals listed but no image to show where fitted. Suggestions pls. Kevin Link to comment Share on other sites More sharing options...
DanMi Posted May 11, 2018 Report Share Posted May 11, 2018 The breather is a cylindrical 'bolt' on the top of the overdrive main case. The seal is fitted by undoing the retaining bolt on the rear of the OD case and pulling the speedo unit out. There is a gear which then pulls out of the brass bearing. The bearing is made in 2 halves which just screw together though may have a tiny pin which needs drilling out. The seal sits in the middle. There is also an o ring around the bearing. If your not sure just phone one of the OD specialists, they will have a complete new bearing unit, are very helpful and in my experience if it has a pin in the £30 or so is well worth it. Link to comment Share on other sites More sharing options...
DanMi Posted May 11, 2018 Report Share Posted May 11, 2018 A D type overdrive is a d type overdrive so it doesn't matter what car it is listed for (well they may have different output flanges and the number of teeth on the speedo drive varies but basically identical. I would deal with the overdrive guys mentioned not the normal suppliers as they have the knowledge and parts. Link to comment Share on other sites More sharing options...
Kevin.payne.15 Posted May 11, 2018 Author Report Share Posted May 11, 2018 Thanks All Ok so Breather found and looks cleanish - before I remove and find myself in a mess - how do you check correct operation ?? Is it simply blow with an airline and see if it gets through?? Kevin Link to comment Share on other sites More sharing options...
Pete Lewis Posted May 11, 2018 Report Share Posted May 11, 2018 its a very simple plug with a hole horizotally drilled , just a look or blow by mouth is more than adequate i had some breathing on my Vit6 so removed the so called breather and added a plastic tube solved any splash carry over . Pete Link to comment Share on other sites More sharing options...
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