Servicing cup and cone bearings - degreasing?

[Sweep]

Have serviced a few hub bearings.

Just doing a bit of revision on tips before embarking on some more and have found a fair few references to degreasing before regreasing.

Is it really needed?

I've never seen the need for anything more than just giving everything a good wipe to remove old grease and any contamination which it contains.

Then put more of the same grease back in - Finish Line teflon.

[Brucey]

since I usually have a can lurking about the place, and it works very well for this, I usually clean the balls by giving them a squirt of GT85 whilst in a clean rag. Ditto cleaning the raceways.

It is not that the old grease would have been a bad source of contamination necessarily, but clean balls and raceways are much easier to inspect for damage.

Since the oil residue left by GT85 is rather thin (and if the balls are not dry they don't stick in a bed of grease very well), drying the parts with a clean tissue or two is the best option.

Another handy thing is to be able to pick the balls up using a screwdriver with a magnetised tip.

cheers

[Sweep]

Another handy thing is to be able to pick the balls up using a screwdriver with a magnetised tip.

cheers

Thanks for the reply brucey.

By chance my ball ended allen keys (Pedros?) are magnetised and ideal for this, though I was unaware of that added feature when I bought them.

[mercalia]

I just decant the balls onto a piece of kiitchen roll then roll them around with another bit on top, removes the old grease

[Brucey]

I just decant the balls onto a piece of kiitchen roll then roll them around with another bit on top, removes the old grease

yup, but x10 faster and x10 cleaner with a little squirt of GT85 as well

cheers

[andrew_s]

Is it really needed?

I've never seen any need for more than a rag, myself.

[Sweep]

Yes, am inc!ined to agree.

I find an awful lot of things on a bike can be sorted with a rag of varying degrees of oiliness.

[JohnW]

I just decant the balls onto a piece of kiitchen roll then roll them around with another bit on top, removes the old grease

yup, but x10 faster and x10 cleaner with a little squirt of GT85 as well

cheers

I doubt that Brucey! ............and think about it - is that the environmental destruction caused by little squirts!?1? 10 times faster is a lot faster, and a GT85 soaked paper towel is a bigger mess than one incidentally smeared with a bit of old grease. liquid, free-running GT85 is a messy business - squirt it into the bearing cup, and you've a lot of wiping to do with the oily rag. I'm with Sweep.

There's another aspect of this though - if the bearings are ready for cleaning and re-greasing, and perhaps the removal of crud accruing from even minimal water ingress during a typical British summer, isn't it time to change the balls anyway? - especially if you need GT85 to remove what an oily rag won't.

I can't count the times I've done this down the years, using so many different quality greases, from Black Moly to the 'Finish Line Teflon', to the Campag milky-white grease of times gone by - and the only problems I've experienced have been due to my own neglect.................but never to a lack of oily rags.

[Brucey]

try it and see

[JohnW]

try it and see

Many times - many, many times

[Brucey]

just to be clear, wipe away the worst of it with a tissue or something (I use cheap loo roll) and then clean the rest with a squirt of GT85 and more clean tissue. The (few) tissues which are contaminated with grease can be bagged and used for lighting the fire with; they will burn very well.

Having cleaned the balls etc thusly they will be very clean indeed and any surface imperfections will be very clearly seen. You can carry on wiping till the cows come home and you won't get rid of all the grease otherwise, not if the grease you use is any good.

Some years ago I serviced the hubs on a friend's touring bike before they went on a big tour and I gave them the balls from the rear hub to clean whilst I attended to the other bits. They were still trying to clean the balls and I'd finished the rest of it. They were amazed when I cleaned the balls to perfection in less than five seconds using a squirt of GT85 and a clean tissue. About 3s of GT85 squirt is enough to clean the components from an entire rear hub this way.

I use rags for wiping my hands mainly. When they are grubby they go through the washing machine and are used again. If you use rags for wiping up grease wholesale, you soon end up with a very greasy rag which is then good for nothing, since it will attract dirt like nobody's business and be utterly useless for any further cleaning duties, destination landfill.

No-one uses rags professionally for serious 'cleaning' of greasy parts since they cannot be relied upon to clean properly (certainly not more than once) and don't allow good inspection of any (wear) debris you might find either. If you think there is wear debris in the greasy residue on a tissue, you can wash it down (with more GT85 or w.h.y.) and the debris will be filtered out on the tissue's white background and clearly identifiable under a magnifying glass or a low power microscope. You can't do that with old rags.

cheers

[Gattonero]

I think is very much related with what you are actually dealing with.
A basic Shimano hub with many thousands of rough miles that is not 100% good, won't get any harm by the very small lint left by a tshirt used as rag. On the other hand, some fabrics may leave some noticeable lint and that's surely not good, but some low-quality tissue can leave lint as well, so you may never be sure about.
The thing is, we're not talking of servicing hubs for a bike that' going to a Commonwealth Track Race. The "average Joe" that is in doubt about possible contamination inside his hub, he better use new ball bearings and new cones as well.
A good method is to use a clean rag only once for delicate parts like hubs, then reusing it for wiping off brakes/derailleurs, and last to scrub the chain. Very delicate parts like suspensions or disk brake calipers are better done by using quality tissue.

[Brucey]

IME if you don't clean parts thoroughly you have missed half the benefit of bothering to take them apart at all, which is to be able to inspect them properly. To do this they need to be properly clean, and there is absolutely no reason to spend longer than necessary 'cleaning' parts, especially in a way that still leaves them dirty and difficult to inspect.

cheers

[Mick F]

Take out all the bits, and immerse them in a little dish of WD40.
Wipe dry and clean and inspect.

That's what I do.

[pwa]

I just use a few pieces of kitchen roll. I resist anything like WD40 because I worry that I might miss wiping a bit of it off before regreasing and the solvent might affect the grease. I'd only inspect the balls if the hub had been feeling rough. That may sound complacent but over decades of doing this I have had very few problems in that area.