Bevel Box Leak

[mechanicsavant]

On my way home , I stopped for a break . When walking around I noticed the right side of the rear tire streaked with oil ! So , I stopped by an auto perts store got a jug of diff lube . Got to a rest area & proceded to check . Diff. Wasn’tunreasonaby hot , a bit warm but I just came off highway . Fluid level was only down an ounce or so . Rode the final 100 Mi. Home OK except for oiled rear wheel .
Got it on lift , just slightly low as before . Remove rear wheel . I don’t see s thing obvious . Decided to remove Bevel Box & let dealer reseal it (the oil has been in about 4K Mi without issue ) . When I went to drain it just a tiny stream of oil came out . I loosened up the fill plug & removed the drain plug again . When I removed fill plug oil poured out . Plugged vent ??? Remove bevel box . Pinion seal & driveshaft housing have an ounce so of oil & drain hole looks to have been main leaker ! Anyone else had a breather “issue”?? Thanx in advance for the help . I’m Going to have dealer reseal & deal eith breather !!

[guzzisteve]

Model? Yes, breather clogged, by your description. It unscrews, unplug it w/compressed air & brake cleaner.

[Vagrant]

We don't have a clue as to what bike you are talking about.

[mechanicsavant]

Sorry it’s 21 V7/850 Centanario . Just went out to see how my other Guzzi final drive drained it’s A 2016 V/7 II . Final drive drained in about 30-45 seconds . The breather on the V7/850 is quite recessed. Non of my 17 mm sockets will get in there , I may sacrifice a craftsman socket & grind ti down

[Tom H]

Just unscrew the level plug when you drain the oil on models with the recessed vent, that will let the oil out quickly. Also use it to fill the box. A funnel and some small hose will do the job.

All of the V7's I've changed the rear gear oil on have drained out very slow until the vent has been removed. Then it pours out.

That recessed vent is a pain. Only way I was able to get one off was with the rear wheel off and an open end wrench. Maybe, as mentioned, a socket with the end turned down thinner might work.

Tom

[mechanicsavant]

The V7/850 has a different bevel box than earlier models . I’ve removed it ,and even on a bench there’s no possibility of getting a wrench on it unless you split the unit.

[Vagrant]

It might be too late for you but, I seriously doubt you have a issue other than over filling. If you go 1 CC past the 160 CC's called for it's going to spit it out. If you haven't sent it off yet, I'd just re-fill it with 155CC of oil and see what happens. So far, I've been lucky enough to fix two v7's this way.

[mechanicsavant]

No, it’s not overfilled. The fluid has been in for 4K Mi. & just started covering the right side of the rear wheel in the last 200 mile ride home from the Adirondack Mtns. The only area that seems to be leaking past is the pinion seal &coming out the swing arm drain hole .As a test I compared drain times between my MkII & the V7/850 .the V7Mk IIdrains much faster , which leads me toward a breather issue . Today’s job is to try to remove the breather . I’ll have to grind a socket down to hopefully get good purchase on the breather & unscrew it . I’m also going to replace the pinion seal as soon as I get a new one.thanks to all for the help !

[mechanicsavant]

I was trying to figure a way to check the breather without sacrificing a socket . I ended up setting the bevel box on the bench upside down using some wood blocks to stabilize it . Then poured about 2oz. Of rubbing alcohol in the drain hole . Bingo it drained out the breather! It isn’t blocked & most alcohol is in the drain dish ! So I’m going with a pinion seal as that appears to be the culprit. Coming past the seal &draining out the swingarm hole