Drive box stuck on swing arm

Another problem in pulling this 1981 Spada apart.The outer oil seal in the drive box has been leaking so I set abbout getting at it. I’ve done it before and know the needle bearing sleeve has to come out. That’s not the problem.Having stripped out the crown wheel, I unbolted the drive box from the swing arm and detatched the suspension unit. But the drive box will not come off.It doesn’t seem to be held by corrosion on the 4 studs or the bearing carrier, as very slight movement can be seen there.My fear, and only idea so far, is that the drive shaft and sleeve are rusted to their splines.I’ve never known that happen, but what else can it be?

This is actually not uncommon.
Also you can get rust build up in the sleeve connecting the two parts of the shaft which needs cleaning out.
I have destroyed a gearbox by forgetting this.

Ok, but how do I get it apart?

Can you soak it all in paraffin or diesel? will act as a penetrating oil and may help.
A block of wood and a few blows with a club hammer or copper mallet may help loosen it all up?
Not actually experienced this before so just educated guesses as to what to do. Just THINK carfully before applying excessive force to any component. That said corrosion can lock parts together very firmly indeed.,

I can’t imerse it in anything without getting the swing arm off. Even then, what is there to drive against.The lip of the steel bearing carrier at the drive box provides a little puchase fo a drift, but everything feels very solid.The last ditch solution is cut the swing arm away and get a 2nd hand replacement. Drastic, but without any other way in, what can I do?

I think the swinging arm will have to come off.
Then you can pour a releasing agent down the shaft tube.
Best to do so that a complete strip down to find any other corrosion / problems.

Yes, I’m coming round to that way of thinking. One ray of sunshine is that at least the swing arm adjusters are not ruted in place.

And of course use plenty of copper grease or its more modern equivalent when re building.

O yes! if the PO had, I wouldn’t be in this fix now.

Have never had this happen, normally if I undo the 4 nuts it virtually falls out. Is it possible someone has had it apart and put a load of gasket goo in the joint and it’s glued the box to the swingarm?

Had this problem before and got the drive box off by fitting some spare sacrificial nuts on the upper end of the studs and placing a block of wood over 2 at a time a good clout with a lump hammer freed off the corroded splines. Be judicious with the wacking as the studs are in an alloy casting.Cheers, Gerry.

Question ~ can you rotate the box on the swingarm tube? It should be able to slightly. Actually you have to to align the wheel spindle properly on reassembly. If you can turn the box but it won’t come off, then OK shaft components could be rusted together. I’m assuming shaft rotates as normal. (?) If you can’t rotate box, then it’s stuck to swingarm, and shaft may be OK and not be rusted.

Don’t tell me let me guess If splines aren’t greased at the factory and nobody looks inside afterwards to check they’ll go rusty (?)

Yes and as I’ve said rust builds up in the joining sleeve eventually forcing the UJ into the gearbox with disasterous results.
This happened to me when I bottomed out hitting a pothole in Germany.
Give the old girl her due, she kept going until a few thousand miles later I had to work on the clutch.

If you can see a very slight movement, soak it in WD40 on the joint and keep rocking it back and forth, that movement will get bigger, but be patient. Try also a bit of heat to help, One of them hot air paint stripper guns are great for i.

Success!3 days of feeding Plus Gas (WD40 is not a penetrating, oil but a lubricant.Only worth using if genuine penetrating fluid not available).I got the swing arm out this morning with the box still firmly attached.Good news: it looks like the later type of UJ. Bad news: It just fell out of the support bearingDive shaft actually felt wobbly (a good sign) Thought about whacking the gearbox end of the drive shaft, but decided not.Back to the 4 M8 studs that hold the drive box to the swing arm. Theaded some plain nuts on them and with the arm supported, steadily whacked them in turn with a copper mallet, in a way that was just not possible with it still on the bike.Gradualy a gap appeared., but I still had to drift it all the way off.Close inspection revealed hard set sealant on the joint face and all around the studs. Pity the PO wasn’t so enthusiastic with his use of copperslip!Time now to sit back and review the state of play.Support baring/UJ to sort.Fortunately the drive shaft splines are well greased (credit where its due!)I can now get at the back of the gearbox easily, free off the clutch lever pivot pin, O rings on the clutch push rod etc. But having got this far, should I have the gearbox out, fit a deep spline clutch, and do the crankshaft oil seal.I know I really should.Time was when I could do it all in a weekend. Dodgy back means I have to take it in stages.
g5er2013-04-11 09:44:14

Yes I know.
Got a Garmin 660 delivered yesterday, opened the box and was horrified at what looked like the complexity of fitting it.
Made myself a roast pork dinner, had another look and should be easy.
Halfnut, if the bloke reads this make sure he is sitting dow. I did follow his advice eventually.

g5er, while advocating if it ain’t broke… now you are in a position to take the gearbox/bellhousing off, well worth a check on the clutch, seals etc. but why replace if they are doing the job? As regards the UJ/support bearing, biggest problem used to be bearing seizing, the UJ should be a sliding fit, probably worth replacing the bearing which can be bought from many bearing suppliers quoting the number on the body, also check the UJ for any play and then reassemble and enjoy.Cheers, Gerry.

Yes they invariably become loose. So this is not unusual. I think this is because of sideways forces. You could try replacing with threadlock, after first establishing how much play there actually is. Otherwise may mean new UJ and bearing.

Close inspection revealed hard set sealant on the joint face and all around the studs. Pity the PO wasn’t so enthusiastic with his use of copperslip!

Thought it must be something like that, it’s not normally that tight! But why? Oil leak? Or just over-enthusiastic?
Mike H2013-04-11 17:50:36

When you get to putting it back I replaced the 4 nuts with acorn nuts and a snoor washer they have never come undone but the acorn nuts keep the crap out, worth replacing gearbox stud nuts with acorns or nyloc in stainless well worth the investment.

There are also acorn nuts available for the wheel spindles and any other exposed studs it saves ages when having to dismantle the bike