Carc / Swing arm leak

It's a huge peg nut socket.

JohnA wrote:

Thanks everyone.
Since Pete mentioned putting locktite on the nut that holds the seal in place, it makes me wonder if the nut has come lose and that's why it's leaking. So I really don't want to put an additive in. I think it needs "open heart" surgery unfortunately.
And, it could be leaking from the drive shaft side, although I feel that is unlikely.

Nah, it's not the seal holder that needs Loctite, it's the pinion nut. Without taking one apart it's pretty difficult to explain how the whole assembly goes together and because the reactive bridge is not seen as a repairable part there are no exploded diagrams showing the parts that need attention.

The reason the pinion nut can come loose is because the pinion bearings don't have a solid spacer. This means that the nut relies on a very light preload and a lockwasher to keep it in the correct position. There are a number of factors that can cause that preload to be lost and once that happens and the nut starts to move about it will eventually snap the securing tabs off the lockwasher and flog the threads out of the locknut. Once the preload is lost it all goes to hell in a hand basket really quick.

The thing is that scenario is rare. More importantly it can be treated preemptively and the risk mitigated bythe use of a few drops of Loctite 290 or, if it is caught early, replacement of the nut and lockwasher and use of some 'Green' "You're never coming apart again ever ya bastard" Loctite. The trick is preloading the pinion bearings correctly when doing up the nut as, not having a solid spacer, you can't just crank it down till you fart! There is no preload specified in any manual as, once again, the component isn't meant to be rebuildable/repairable so one has to just go to industry standards for such a set up and in an application like this 80-120 inch pounds seems to be about right. That will hopefully preload the nut sufficiently that it won't want to come undone but at the same time won't apply sufficient crush to make the bearings overheat and fail.

Loosening pinion nuts are rare though so let's not get into the whole 'Sky is falling' mindset. It can easily be checked when the seal holder is removed simply by poking at the nut and seeing if it moves in relation to the pinion shaft. The blown seal is far more likely to have done it's dash because the box was overfilled, the vent was blocked or simply because it was having a 'Bad Hair' day. Try not to overthink it or look for problems that probably don't exist!

Pete,
I don’t understand how the bevel box can be overfilled when we’re supposed to fill it to the top of the fill opening. I did take the top vent “doohickey” off and blew it out and out it back on, but no difference. So I’m thinking...a bad hair day. It’s sadly sitting at the shop in line to hopefully get fixed next week.
This new Guzzi shop had a fairly new eldo and California in for service and the Guzzi mechanic told me he had a GRiSO in that was leaking between the engine and transmission. I didn’t see if to see what year that was. They tell me they have done well selling the V7’s and V85’s.. Aprilia’s are selling very well too.

I fill CARC's to the ledge on bottom of threads for fill plug. That's me, seems the amount is a bit much for it.

If that G is an early 8V it may be the long bolt deal by rear main, bulletin on it.

Well the guys at the new Guzzi dealer where I live (already have had Aprilia and Vespa)appear to have done a nice job fixing my pinion shaft leak (diagnosed by Mr Roper). I did take them instructions from  Pete just for my piece of mind. They only charged me $600 (5.5 hrs of labor) to do the job and install 2 new tires (pirelli Angel GT). They didn’t try and finesse the rubber dust cover clamp off off and did spit the Carc. Probably after seeing your comments, Pete. Thank you for all your help. There’s a beer or two or three.....waiting for you in Savannah.

Good-o. It's nice to actually get a bit of feedback on the endgame with things like this. So often people ask for advice or come looking for a fix for a problem and them when people have spent time and effort explaining things the OP will simply vanish.

It's not just me, it happens to other people too and is very vexing. It's not that thanks or adulation are wanted or needed, it's simply good to know whether a problem has been solved. If it has? So much the better! If it hasn't, or the explanation was wrong or unhelpful or just too difficult to understand then such advice can be modified next time around.

Can anyone give me the numbers or sizes of the carc seal and gearbox seal that may be leaking?

cheers Terry

Also any thoughts on what can i cannibalise to make these special tools for the carc seal assuming that's the one leaking.
Judging by the forum chat most likely carc seal.
Will find out tomorrow night.

cheers terry

Terry,
The pinion seal part number is GU90404558 and was $36 USD and was available. I got it in a week. I also ordered the seals on the gear box end but didn’t t need them as Pete suspected. They are GU05547930 and there are two of them. There is a special tool needed for the pinion nut that Pete also mentions in this thread. The shop I took it to had one. The schematic for all of this is on page 23 of 95 in our shop manual.
Best of luck.