Swing Arm Gearbox Seizure

[Swarfcut]

 Recently came across a S/A box which has suffered water ingress and every part is rusted solid. Now I know these are still reasonably plentiful, but I was thinking of what is salvage and what is scrap. So how to get it apart without too much violence? Heat and big hammers? Let's try a different approach.

 With the covers removed all that's left are the rusted shafts, gears and selector forks, along with the camplate and selector shaft.

 Methinks sacrificing the camplate pivot will allow the whole of the seized internals to be drifted out along with the selector shaft, forks, camplate, mainshaft and layshaft.

 So the question is.....How tough is that pivot? Is it possible to drill down the centre to weaken it, or is it as hard as a diamond to withstand the constant camplate movement?

 Reckon there is no way to get the selector shaft thro' the forks, the usual manner of attack.

 Swarfy.

[Roger (Doomtrainbarx)]

Throw it in a bucket of diesel for a week.

[CheeserBeezer]

I'm guessing the pivot is very hard. Is it possible to get the nut off the pivot and punch the pivot into the gearbox from the outside? I'm not sure how far the pivot would travel inwards before it hits something, but maybe worth a try. I think the main problem you'll have is removing the grub screw which holds the selector shaft in place. They can cause problems even in decent gearboxes. Have fun.... but I'm not sure why you're bothering!

[Swarfcut]

 Thanks  to all for those helpful thoughts and time for a reality check.

 Is it worth bothering? Probably not. Can Science assist with very little effort? Maybe.

 As well as diesel, anyone tried molasses or other type of de-rusting soaks?

 Swarfy.

[Catz]

I've heard of people having good results with Coca Cola.

[groily]

50/50 acetone and ATF? Has worked quite well for me over the years, and I think musky or someone mentioned it on here the other week  . . .

[Angus]

Be careful with Diesel, I put a goodish set of +60 A7 pistons and rods in Diesel to free off seized pin circlips and then forgot about them for a few years. When i Found them again they were covered in a deposit that wont come of and the circlip are still stuck 

[RichardL]

I'm not a chemist or metallurgist, but I believe there are some here (BSA_54A10?) who can set me/us straight on this. I hear two kinds of solutions (figuratively and literally) being recommended here, those using acid that dissolves rust, as in Coca-Cola or molasses, and those creating penetrating oil, as in diesel or acetone/ATF. It seems to me that the first thing to do with these heavy encrustations is to dissolve the rust to see what you have, then, see if penetrating oil/fluid further loosens once-moveable parts.  This said, I suppose there is only so far one should go with acid methods when the parts sit within an aluminum housing. 

No comment on why you're bothering. I think CB has a better perspective on that than I.

Richard L.

[Slymo]

Molasses 20:1 in hot water leave soaking for 10-14 days or longer. works a treat. White vinegar probably a bit quicker although I'm not sure its as gentle.

[Swarfcut]

 Looks as if it will go in the soak. I agree that it must be a two stage process, rust removal and then free off.

 Molasses is the front runner for now, and to be honest I have enough rusty bits to make a test comparison between the various methods on YouTube. Some of the homespun chelating formulae look interesting, and being neutral, supposedly do not attack the base metal, only the rust. Reckon buying  raw chemicals in the UK puts you in the terrorist spotlight, but molasses probably carries a diabetic health warning....

 Time to get stirring. I'll report back at some stage.

 Thanks folks,

 Swarfy.

[Colsbeeza]

I have used molasses very successfully on rusty steel parts, but do not know how the gearbox aluminium would fare for 10 days or more in a molasses bath.
I dissolved molasses in hot water, then diluted it to about 10%. I made up a 130 litre solution to soak the BSA mudguards. You must first remove as much heavy rust as you can. After 10 days, you scrape off the one-inch thickness of mould from the liquid surface to find out what's underneath.
Col

[Slymo]

Yes definitely an outside activity. As well as developing the aforementioned mold there is a foul sulfurous odour. Its fine with aluminium in my experience and remarkable with anything ferrous. I left a very scabrous seat pan from my SR in a bucket for a couple of weeks while I was on a holiday and came back to a completely clean grey surface. On drying it the surface began oxidizing almost instantly with a fine orange rust but a coat of a zinc primer sorted that as would a wipe with an oily rag for those bits that don't want paint. If you are anywhere rural the cattle feed molasses is by far the cheapest option. If not then I can assure you 5% is an effective mixture although 10% might be quicker I suppose.   

[muskrat]

G'day Fellas.
I won't use molasses for rust removal. I prefer it on toast
Back in the 80's I had a produce store. I'd buy molasses in 44 gal drums and bottle it in 2Lt jugs for the horse owners to mix with the feed.
At $25 (12 quid) for a 16Lt drum and the dilution rate you could fill a tub big enough to do a frame.
Cheers

[RichardL]

What, not Vegemite?  (I couldn't remember the name of it, so I just Googled, "Disgusting Australian spread for bread." Of course, Vegemite came up immediately (it probably does that a lot, anyway). I don't think I've had it since I was in Sydney in '76.

Richard L.

mod edit: try it on a cracker with cheese & tomato, yummmm

[KiwiGF]

Are we off topic? Vegemite is a very poor copy of British MARMITE    (I say British as there is an NZ “Marmite”, also a copy).

The NZ authorities have banned the import of British Marmite as it infringes the copyright of the NZ marmite, but its not illegal to have British Marmite in yr luggage as long as you declare it, so there is still a good supply of the real good stuff in NZ. The guys at NZ customs just raise their eyebrows when you declare the food you are carrying is British Marmite and waive you through…pretty much every Brit has a jar.

If desperate as no mates have brought you back a jar from a UK trip there is a rebadged British Marmite sold for extortionate prices in NZ supermarkets and not quite tasting the same as the British version. Called Ourmate.

Spreading Vegemite on rusted parts is probably a good use for it (there you are, back on topic  )

https://www.countdown.co.nz/shop/productdetails?stockcode=236531&gad=1&gclid=CjwKCAjw5MOlBhBTEiwAAJ8e1uMuIYMs-dpkJ12LP1BkTSz8I0JqqD9HozfbVI6tPMadx2vIrn-v2xoCzKQQAvD_BwE&gclsrc=aw.ds

And this locally made stuff (by a company that maybe stole the Marmite name) is revolting

https://www.countdown.co.nz/shop/productdetails?stockcode=79628&name=sanitarium-marmite-yeast-spread