Morning All Not sure how this will be displayed on the forum with text and photos added... so please bear with me Who at Ducati thought that fitting brass nut inserts into a plastic tank was a good idea I had to remove bodywork for a few maintenance checks and to fit crash bars first hurdle, you you've guessed it, spinning nut inserts ! so I had a ponder, squirted some Penn oil, had a brew, tried again, still no luck. decided the only way was to drill out the fixing. I did notice that before going any further, that there were tool marks on the panel around the the fixing so out came the cordless drill and a 4.2mm HSS drill bit, managed to remove the head of the bolt, and the bodywork, which revealed more tool marks around the nut insert on the tank Carefully I manged to drill down the centre of the stuck bolt/nut insert with a 4.2mm drill and clean out the threads with a dental pick and M5 plug tap, deep enough to get a new fixing in (didn't want to go too deep in case I went through the tank) so another brew and ponder was required, how to stop it happening again.. I came up with an idea of using a M5x16 grub screw, M5 half nut and a plastic Top hat spacer quick measure up of the slot in the bodywork, and thickness with the trusty verniers, fired up Fusion 360, and came up with this Using Prusia slicer, and 3D printer, out came these screw grub screwed into nut insert and place top hat over the grub screw then secure with half nut use an Allen (Hex) key to hold grubscrew while using 8mm spanner to nip up the half nut. No torque applied to the nut insert repeated process for another spinning nut insert Thanks to Ducati designers, I drink a lot of tea! hope this helps if your in same boat as I was this morning I'm happy to post out top hats to anyone requiring some ( A beer token or two should cover the cost) Happy biking Neil B
That's good work, and yes, it was a daft idea to design them that way in the first place. And there isn't really anything you can do to stop the moulded in nuts spinning once they've started. I have 1 on one side and 2 on the other side that have gone this way on my 1260 Enduro. I have to admit that realising the plastic is both flexible and thin I managed with a little brute force and twisting to pull the inner covers off over the heads. I then keyhole slotted the covers to make them easier to replace. Obviously I meant to do something 'better' along the same lines as you've done, but once the outer covers were back on I conveniently forgot about it.
Many of us on here will recognise this and sympathise i feel sure, as similar happened in many locations on the original Multistrada 1000DS and derivatives and also 848/1098/1198. I don't know why Ducati have stubbornly stuck to this design over the years as the solution is only minimally cost-related plus they've had years to realise that there is a problem*. I'm not going to include the answer as bound to get shot down, but it's simple and obvious, and i can say with confidence that many of my ex-colleagues would have come up with exactly the same solution. * I don't believe this was intended within "planned obsolescence" approaches or anticipation of owners buying replacement items.
Lots of silicone grease and just nip them up when fitting. Did one a few months ago, what a bugger of a job
I'm confused. If the insert was spinning, and you haven't mentioned remelting the plastic or getting super glue out (not that it would stick to an HDPE tank anyway) how did you manage to tap it? Did the heat from drilling it remelt the surrounding plastic? Looks like a neat solution given you can stop the stud spinning with an Allen key.
Morning Well, "Spinning" its more of a "camming" rotation with some friction, it seems that in a Counter Clockwise rotation that the nut insert will cam round, its possible that there is some galling between the screw and nut insert (hence DucV2 recommends some silicone grease, I use copperslip), which instead of allowing the screw to release is causing the nut insert to cam round, I guess if you attack it with an impact gun or cordless drill with a hex key adapter the insert would spin freely after a while, While in the Clockwise rotation (drilling and tapping) these seems to be enough friction between the plastic tank and the nut insert to allow drilling and tapping to take place (the screw is very soft and easy to drill out) it could be the design of the insert which allows it to grip the plastic better in the clockwise direction? regards Neil B
All three of the effected inserts on mine are spinning freely in both directions. I'm assuming somebody in the past has just kept spinning them in the hope they'll grip. My plan is actually to dig them out, and either glue in new inserts or fill the holes then drill and tap them(carefully) for Helicoils. I've found in the past that the formulation of Gorilla GEL Superglue appears to stick to most moulded plastics, so I'm hoping that will work.
Ah that complicates it a bit :-( if you use a dremel with rotary burr you may be able to cut the insert into 2 or 3 pieces, working from its centre, then once it removed, either use another M5 insert with Hysol (9466 maybe?) epoxy or maybe go up a size to M6 ? Not sure how well hysol or any other adhesive will stick to the tank as Markyd as stated Be good to find out if Gorilla GEL superglue is a good one to stick the inserts in with
I admire your approach to this problem, and the main thing is that you got over the hurdle(s) and the bike is back on the road. Forgive me for not reading all comments on the thread, are these inserts in the fuel tank? because if they are, there is nothing you can use in the form of a glue that will bond to it successfully, certainly as far as I'm aware. Please prove me wrong, i would be happy. You might can all the glue around until it sets and appears to be bonded to the tank, but it won't last long, just due to the nature of the material it's made from.
I'm hoping the Gorilla GEL superglue is going to work, I'll mix in some talcum powder to bulk it up a bit. It's the only superglue I've found that sticks the standard Ducati moulded bodywork successfully, so might work. It has to be the GEL version, not the normal stuff, it's different, but I don't remember how.
Ok, seems glues are not the long term solution, has anyone come up with a long term fix for this rubbish design once the nut inserts start to spin freely ? As Nasher has mentioned Helicoils, is there enough meat around the insert to dremel the insert out and install a helicoil ?
I don't think the glue(or anything used that goes from liquid to solid) has to actually stick to the tank, or even the insert. All it has to do is dry hard around the new insert and into the shape of the recess in the tank. The irregularities in both will them stop the insert turning, you're not going to torque them up hard.
Oh don't worry Chris, it's not even a priority for me to get around to trying at the moment, and when I do I'm expecting to have 2 or 3 goes at it.
I can however ask for an expert opinion. I have two different injection moulding suppliers that I spend serious amounts of money with. They might be able to recommend something.
At work if we want to add Inserts manually into a Lexan or similar sheet, we put the insert on to the end of a Soldering Iron, get it nice and hot then push it into a slightly smaller hole in the sheet. I don't want to do that with my petrol tank!
