How to change rear hub bearing in 45 min. No dismantling.

[donlambretto]

Yes! it can be done
After doing the engine rebuild and fitting a substandard indian bearing (unknown name) which had been fitted in a MecEur bag (I suppose by the person who sold me the "project in bits") and blowing 2 seals in no time, I just did not want to undo all the engine and gearbox to change one bearing.
I decided to make use of my bodge-landrover-knowledge and thought, what if I pulled the bearing from outside?

You will need welding skills and equipment, and a decent 2-legged puller. I did not have welding skills nor equipment, so the task was kindly executed by my local bike mechanic.

Be sure to have some protection around the layshaft as temperatures are very high and bear in mind that the alloy can melt, so it needs to be both proper and carefully done

Besides, the heat also makes the bearing removal very easy.

1.- Old (failed) bearing in place. Note protective sleeve of aluminium foil around to protect layshaft against sparks and heat


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2.- Nuts welded to permit puller do its job properly


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3.- Puller in place, baring getting out


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4.- Out with the old, on with the new


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5.- Used old stock but mint serveta bearing in place


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So, 45 minutes, no dismantling
Bear in mind that your scoot can burst up in flames due to a flying spark from somewhere.
Be very careful with that issue. Place plenty of non flammable protection around.

Besides, shimming is critical. Old stock original bearings and RIV and indian bearings did not give shimming problems. Besides original shim was left in the rebuild and that was why I could dispense with the side casing manouvre.
The result was very satisfactory and I'm very pleased doing a 9 hour job in just 45 mins and wanted to share the mother of all bodges.

Happy monday to everyone

Cheers from Spain
Robert

[byron]

innovative, but i do like to shim the gearbox after fitting the rear hub, sometimes the layshaft can be pulled through more as the hub nut is tightened.
did you change the layshaft o ring...?

[Muppet]

I knew there was a way it could be done without welding and with the endplate and gearbox still in place; but that looks like hard work,

muppet,

[donlambretto]

innovative, but i do like to shim the gearbox after fitting the rear hub, sometimes the layshaft can be pulled through more as the hub nut is tightened.
did you change the layshaft o ring...?

Hi there,
I checked the end float and there was no in-out movement and the layshaft was very smooth, so I assume shimming was spot-on.

In the early days of Lambretting (Lambretta home workshop manual) it was suggested to drift out the bearing retainind the end plate in place, and usually the stock shim was retained.

The o ring was in perfect shape so did not change it, could have taken it out with a needle or melt it partly with a soldering iron
I went for a ride and gear selection was very very good and smooth.
Cheers

[mickdale]

you have damaged your engine case?

from the picture it shows the cast "lip" outside the bearing has molten?

[shocky]

you have damaged your engine case?

from the picture it shows the cast "lip" outside the bearing has molten?

to be fair that lower stud mount looks bodged to fcuk anyway and that layshart looks iffy to me each to there own though. id do that but use my tig welder and on the bals in the bearing and not the outside BUT only as a get me out of the sh1t bodge

[tonydevon]

great get out of jail quick tip, but not sure I would use it if I had the time to do it properly.

I would have wrapped them studs with something to stop any spatter getting into the threads as well.

did he preheat the whole area or just go in and weld straight to the bearing case?

but all that aside, if it worked and your happy with it, then hey its your ride

[donlambretto]

No, don't worry, this was left by the previous owner, as well as very nice crack besides one of the retaining plate studs, so the stud was pulled whenever the nut was tightened.

I commissioned the stud hole to be welded, refilled, re tapped and screwed again.
The small missing bit besides the bearing was left as is, as it was structurally sound

Cheers

[CPH Lambretta]

There is no need for all that, there is a bearing puller that does the job in 5 minutes with no welding or heavy machinery.
We used them all the time when I worked as a scooter mechanic a few years ago, but that was on Vespa PXs, don't think I'd use one on a Lambretta because of the shiming problem.

[paulmgreen]

9 hours to do it the correct way??? Does that include cooking a meal for 6 and watching Titanic in the middle of changing the bearing ? Lol.