V50 II – Drive box/Swing Arm separation

Unlike the big block twins it’s easy enough to pull the swinging arm on and off without bothering to unbolt the drive box from the arm. This meant that on my original set up I never even tried to do this until a seal in the box went and I wanted to split them so at to just send that part to Nigel (NBS). I ended up having to cut the nuts off, and then the s/arm off – sawed across the corners of the studs. I then got another arm from Pete (Reboot). I put that back with plenty of grease, and four stainless dome nuts. Tried separating these last night whilst I was investigating (see) ‘Graunch’. Nuts come off sweet as you like, but the studs appear to be stuck firm again. Looks like there could maybe have been some electrolytic forces at work here. Has anyone else come across this? Is there some approach I can go to – some magic fluid that will work adequately as a release agent? I don’t need to make the separation at the moment, but I should probably aim to sort this out before I need to even if that means resorting to the hacksaw and yet another arm from Pete. I guess with hindsight pulling and re-greasing annually wouldn’t go amiss.

Stainless and alloy don’t mix at all well. Â Try hot water to remove the worst of the alloy corrosion. Knock it about a bit with a dead blow hammer and then some heat, I’ve used a hot air paint stripper on parts and it works well for smaller items.

soaked the threads and area where the threads meet the swing arm on mine in plus gas for a few days and some GENTLE persuasion with a rubber mallet got it moving easily

Yeah - I put a nut on one of the studs and had an exploratory tap with a 5lb club, but these look well corroded. Best I set about the soaking process … with a little heat from time to time. Note the studs themselves are not stainless just the acorns that I used and which come off fine.

Daft question time ~ why do the studs have to come out… ?

[quote=“cyclobutch” I don’t need to make the separation at the moment, but I should probably aim to sort this out before I need to [/quote]

yes dam good idea, easier to sort out at home than on the side of a road, if you do need in the end to yet again set a hacksaw to it there are a couple of V50 s/arms with drive box on e-bay right now, item 111614356482 and 191530959707 but the first one is listed as V50/65/75 which is incorrect if it came of a V50 as it will not be right for later V65 SP models, no idea if it will fit some or all of the V75’s, and the drive box is still bolted to the s/arm, so it might or might not be as per your item and have stuck studs.

Doesn’t really matter where the stainless is the cathodic corrosion will still take place. Â You need to use the correct grease as well, but not Coppaslip as this will make things much worse. Â Aluslip is a good compromise. Â Worth noting when you come to reassembly.

Thanks folks - and all duly noted.

Found this ~

Just FYI, not yet had any problem with SS fasteners in alu alloy casings… the blurb says why… note also says copper is better next to SS…

Strangely the marine industry will (in general) not recommend Coppaslip as it accelerates electrolysis. Â If you do the sums and add rotating machinery into the equation you’ll see why copper is a bad thing. Â It should also be noted that some greases and oils can speed up corrosion due to their chemical makes up, which can make for interesting conversations.

As with some many things, Vaseline it is then.

Sounds like I should probably pull and lube these studs as part of my annual service routine (ahem).