Early Cento rear hub bearing

[57Speedster]

Hi Guys, I'm looking for a little advice.
My 64 Cento engine is leaking gearbox oil into the rear brake drum through the hub bearing, (brake shoes are soaked and don't provide any stopping power).
It appears to have the early style bearing, which is supposed to be sealed, (mine has clearly failed), so there is no additional oil seal on the hub, and no space for one either.
The early type, 'sealed' bearing is available, from Lambretta Works USA. The later bearing (which I presume is narrower), the separate oil seal, and the later 'stepped' bearing retaining plate, are all available in the UK. Parts cost is about the same for both versions. why are those bearings so expensive ?
I believe that the clutch, gear cluster and layshaft will need to be removed to replace the hub bearing, and I don't have any of the special tools & pullers to do this.
May need to take it to someone who has the right equipment.
So. Is it really necessary to remove the gearbox to replace the rear hub bearing ? I've seen bearing pullers which can grip the inside lip of the outer race, to draw it out with the layshaft still in place, but they are very rare and that means pricy.
Once it's all out, is it worth changing to the later bearing and separate oil seal arrangement ? (the later type is supposed to be easier to replace the seal in the future).
Any suggestions would be much appreciated.

[johnspeed22/2]

Hi,

not familier with early J sealed bearing however have a Vega with the plate seal arangement and dont see any problem changing to this as the casings are the same in this area,i dont think you will get bearing out without stripping out clutch gears layshaft ect,Camlamb/scootopia can help with special tools if you want to splash out,rear hub bearing can be removed with a little heat on casings with a heat gun and drift out and same when refitting,not sure why bearing so expensive but it cannot be a fast moving part off the shelves being so few J and luna on the road being ridden.

good luck with it and take you time.

[Shaun]

So. Is it really necessary to remove the gearbox to replace the rear hub bearing ?

Main problem if removing the hub bearing with box in place is keeping it all in line.
If you pull the layshaft out a little with the bearing by mistake, the gearbox shim will be allowed to drop and realigning that with the box in would be tricky.
I have never worked on the earlier type, but a phonecall to Scootopia and a word with Dan would sort you out.

[57Speedster]

Thank You Gents,
Looks like I'm going to have to dismantle the gearbox to get a new bearing fited. Thanks for the suggested tool suppliers.
Have discovered that the later (non-sealed) bearing 20050038 can be obtained at reasonable price, direct from non-Lambertta specialists, e.g. General Bearing suppliers, as it is a fairly standard item, with many other applications. I can get the separate oil seal 20050039 and matching retaining flange 20050033 from the usual Lambretta parts suppliers.
I'll let you know how I get on.
Cheers, 57 Speedster

[57Speedster]

Update.
I ended-up getting the proper bearing from Scooter Restorations, (it was on special offer, only £30 ) got a Rolf oil seal and new retaining plate too.
Stripping the gearbox revealed a few other horrors, had to get the case welded to restore damage to the Gearbox end plate dowel holes, so it now has a NOS layshaft, Selector cursor, 1st gear, Endplate with new bearings, and had been re-shimmed. All working smoothly now.