Jocklandjohn Posted October 15, 2021 Share Posted October 15, 2021 I'm replacing the rear shocks tomorrow and this evening in anticipation pulled off the upper nuts which appear to be something odd that requires an 18mm socket (not 19mm as required for M12). I tried an M12 nut on the shock pin and it will go on but not far and not easily so I've not forced it. I've done some googling and its suggesting that an 18mm socket is needed for nuts that are 7/16BSF but also, confusingly, that M12 should be the standard fitment on the upper shock pin. Can anyone shed some light on this for me? Is it M12 or were there anyt imperial sizes like 7/16BSF ever used? Quote Link to comment Share on other sites More sharing options...
Mo Murphy Posted October 15, 2021 Share Posted October 15, 2021 M12 on mine John Mo Quote Link to comment Share on other sites More sharing options...
western Posted October 15, 2021 Share Posted October 15, 2021 M12 Nyloc nut according to the 110 1987 on parts book. Quote Link to comment Share on other sites More sharing options...
Jocklandjohn Posted October 15, 2021 Author Share Posted October 15, 2021 52 minutes ago, Mo Murphy said: M12 on mine John Mo Thanks Mo. Curious, some posts I googled mentioned similar confusions as I'm experiencing. Ah well once I get the wheel off and my head in there and can see clearly to give it a good going over with the wire brush it may all be ok but reaching in in the gloom it would not easily fit, and I wasn't keen on forcing the nut on. Definitely needed an 18mm socket on both sides to get the old ones off, 19mm would not go on either side. 21 minutes ago, western said: M12 Nyloc nut according to the 110 1987 on parts book. Thanks Ralph, if the parts book say M12 well who am I to argue! Quote Link to comment Share on other sites More sharing options...
Mo Murphy Posted October 15, 2021 Share Posted October 15, 2021 You might run a die nut gently down it John, that should at least show you if and where the thread is damaged. Mo Quote Link to comment Share on other sites More sharing options...
Jocklandjohn Posted October 15, 2021 Author Share Posted October 15, 2021 1 hour ago, Mo Murphy said: You might run a die nut gently down it John, that should at least show you if and where the thread is damaged. Mo Aye will do, really dont want the faff of removing the top mounts if I dont need to! Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted October 16, 2021 Share Posted October 16, 2021 Be aware some shocks are M12-fine instead of regular thread, and at that size I think there's 1mm, 1.25mm and 1.5mm versions of the thread pitch. 1 Quote Link to comment Share on other sites More sharing options...
Jocklandjohn Posted October 17, 2021 Author Share Posted October 17, 2021 10 hours ago, FridgeFreezer said: Be aware some shocks are M12-fine instead of regular thread, and at that size I think there's 1mm, 1.25mm and 1.5mm versions of the thread pitch. Thanks Fridge. Job done, but definitely some weirdness in the nuts/threads. Are you referring to the lower nuts (rear) with those pitch variations? Once I had the wheel off and my head inside the arch with plenty light and wire brushed the shock mount I was able to get an M12 (sacrificial just in case) nut to spin down easily enough, and then tried the M12 Nyloc which was ok too. However the nuts that came off are both 18mm spanner size (and not corroded down to that size) and woud not spin onto a new M12 bolt at all. So I'm guessing they must be one of the variations you mention. I checked the security of the new Nylocs on the mount after fitting the new shocks and was easily able to torque up without any thread-slippage so am satisfied the mount-threads are intact so not sure what was afoot there. Anyway, despite the apparent functionality of the old shocks it was just as well I replaced them as they were pretty shot. Have the delights of the fronts to do next which I can foresee involving the electric hacksaw. Quote Link to comment Share on other sites More sharing options...
Mo Murphy Posted October 17, 2021 Share Posted October 17, 2021 The nuts are M12x1.75 pitch HTH Mo Quote Link to comment Share on other sites More sharing options...
Jocklandjohn Posted October 17, 2021 Author Share Posted October 17, 2021 24 minutes ago, Mo Murphy said: The nuts are M12x1.75 pitch HTH Mo Thanks Mo. (Jings this is complicated!). Quote Link to comment Share on other sites More sharing options...
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