Breva 750 Bevel Box Output Seal

Hi All, the output seal on the bevel box seems to be leaking - maybe just a weep or a seep. Anyhow, I have a new seal to put in but looking at the manual, it appears you have to strip the whole lot down to get to the seal.
Question; are there any issues with shimming when the box goes back together?
If I use the same shim and same number of gaskets to put it back together, I guess it should be ok?

Are there any other tricks and tips I need to know?

Thanks for any help.

have you checked that the breather is not blocked up ?
myself I would take it up to Nigel at NBS and let him do it rather than mess about
I do have the manual here and it shows everything about shimming but its no substitute for experience

Do it yourself, and then write an article saying how you did it.

Ha! Thanks Ian, that would seem to be my only option.

You know you are destined to become our lil’Breva guru.
Beard, long nails and smelly feet optional.

Good luck. When my Veefer box sprang a leak I just unbolted it and sent it to Nigel at NBS. But then I have more than enough examples already that amply illustrate my own limitations I guess.

Hello All,
I just found this which helps a lot;
It tells the story for a V50 Monza - :smiley:

I have been following the Guzzi workshop manual and now have the bevel box apart and have pulled off the needle roller inner sleeve, undone the bolts and removed the ring gear. Next the book says to simply remove the hub from the backplate. But the hub is firmly holding onto the inner race of the large bearing in the backplate and won’t budge.Â
Any suggestions?

Must be pressed into the bearing? Aka, ‘interference fit’.

Thanks Mike H but the manual clearly shows the two being simply lifted apart. No special tools or press involved. You are right though, clearly the tolerances are so close as to be beyond a sliding fit. My concern is that to apply any force would mean to use the alloy flange which I am loath to do.
I guess judicial use of heat must be the answer.

Could someone have put it together with loctite?

Ah-ha! Now I know the trick. Although the paper manual shows the two coming apart easily, elsewhere on this forum I found a video version. In this it shows judicious use of a soft faced hammer! I tried this and got it to move about 0.5mm. After leaving the hub out in the sun to warm up a bit, I got the hub out with a few more careful wallops! This finally reveals the large seal which I need to replace.Â
 Now my next worry is to get it all back together again. Oh, the joys of Guzzi tinkering!

Interference fit … :smiley:

Paper manual omits mention of big 'ammer…

Now I have got it apart and got the new seal in. Next I have to get the roller bearing inner race back on but don’t have a suitable sized tube to drive it on with.
Watch this space…

Latest news; Ta-da! All back together.

If you put the hub in the freezer and gently heat the bearing inner race, they just drop together with no effort at all. Simples!