Classic Vespa Front Hubs…
Those more observant readers of Scooterist Scene may have noticed that two previous articles on rebuilding GS/SS/Rally front left an important part of the front end ignored? This time we include this last lost item….The hub!
Bearing up.
The play on the back wheel on the Vespa is left there by the Piaggio factory to bemuse generations of MOT’ers. Every Vespa owner knows the score and patiently explains that the play was there from new, leaving the tester better informed, but somewhat doubtful at the same time!
The front wheel is another story…Vespa front ends already have the dubious pleasure of a long trailing link and a single legged fork – not to mention 10-inch wheels - this adds much the classic handling of the marque, the bad intentioned might remind you of this Vespa trait somewhat negatively? The front hub bearing does not have much to do with this handling aspect of the Vespa, because – if there’s any play on the front hub – you have a dodgy bearing. There is no soft talking the MOT tester when discussing the front hub!
The GS 160/SS 180 Hub Bearing.
There is a basic similarity in Vespa front hubs, but it’s better to treat the varying models in detail – the PX hub, for instance, is a different design and, arguably, an inferior one, at that?
We’ll start with the bad news…This repair can’t be done entirely at home unless you have the equivalent of a bearing press by your bench, sorry! That said, the press is only necessary to push the hub axle assembly out of the hub, but not required on reassembly. Any workshop with a press can push out the hub axle in a minute and may not even charge you the standard £5 to £10 that only the most hard-hearted engineering shop might extort?
Having dealt with the fork strip previously, let’s assume that the hub is free from the forks? The loose hub/ trailing link looks like Pic. 1. If it doesn’t, you have the wrong hub and you can stop reading? It is not possible to undertake this repair with the hub in situ, by the way?
The entire speedo drive must be removed from the hub before attempting this repair, or there is a risk of damaging the worm gearing. The speedo drive is held in place by a flanged14mm cover nut.
The first step is to remove the wire locking circlip. This prevents the castellated nut behind it from working its way undone. The nut itself requires a special type of peg spanner, a tool only held by the classiest of Vespa workshops. This tool can, with a bit in ingenuity, be knocked up from a section of steel pipe. Failing that, the nut can be tapped out with a nail punch (Cries of horror from the Vespa crowd, at this point! The fact of the matter is that, even with the correct tool at hand, the nut has often to be started off with a punch – in any case). Please note: This is a left hand thread
With the castellated nut removed – the oil seal sits inside the nut and is removed with the nut – the bearing, or one of them, is now visible.
If the hub is reversed, it can be seen that there is a circular plate at the opposite end to the trailing link pivot point, that sits behind the hidden end of the front wheel axle (See Pic 2). This plate has to be pressed out through the hub – this is were the press is needed. As the press forces the plate through the hub, the axle and associated bearings will fall out (See Pic 3).
The bearings can now be removed – tapping the axle through the bearings with the face of the bearings held against vice jaws, is one method of so doing. We are now left with the bare axle, as in Pic 4.
New bearings to match the old are now required. Here’s a good tip: Find a local bearing suppliers, they will sell you these bearings for £5 each – for cash. Another tip: Replace the bearings with their sealed cousins and never have your front brakes contaminated with grease, ever!
Tap the new bearings onto the axle. Use an old box spanner as a drift, so the hex face of the spanner sits over the inner ring of the ball race. If you do this you can’t damage the race. Never hit the outer ring, this will ruin the bearing. The axle should now look like Pic 5.
Replacing the axle and bearing assembly is simplicity itself. Firstly press the circular hub plate back into place. It has a neoprene washer to help seal it when pressed fully into position.
Finally, the axel/ bearing assembly can be tapped into place with a hide mallet and snugged up as you re tighten the castellated nut. Easy! Replace the wire circlip (Don’t worry about a new oil seal if you have sealed bearings).
JOB DONE!
[Many thanks to Paul Stevens of Basingstoke Scooter Club for reviewing this article and pointing out that it is possible to knock the axle out with a suitable diameter drift. However, he suggests that using a press is preferable?]