Grease gun overlubrication of roller bearings

[Johny Walker]

Hey guys

 

Since I first started until yesterday, I have always used a greasegun to lubricate roller bearings 'daily' as instructed by colleagues and stickers on machinery. I simply pump until a bit comes through the seal, assume its full, clear the excess and carry on with my day.

 

However I have been reading about machinery lubrication, and it turns out that overgreasing is a huge reason for the deterioration and failure of roller bearings.

 

Overgreasing means that the bearings glide instead of rolling, which compacts the grease and squeezes out the base oil. The soapy residual grease that remains doesnt have lubricating qualities, so the joints wear and heat up, which causes the wax to harden. From here a variety of issues arise, as you can imagine.

 

So as a first point of call, to everybody who didn't know about this, now you do, and its actually pretty important. One of my employers had a flywheel bearing change on his timberwolf which was in a horrid state, and in hindsight it could well have been a result of overgreasing.

 

Now a question for the members who knew and are mechanically minded:

 

Recently, when I've gone to grease the main flywheel bearings of my HB20, I've noticed that grease no longer seeps from the entire seal, and rather just from one point near the nipple. As mentioned before, I greased it before every day of use with a greasegun. It doesn't seem to take nearly as much in as it used to either. I have concerns that my negligence of correct lubrication may have started to lead to the aforementioned issues (build up of hardened waxy grease). Its important to note that there doesn't seem to be any excessive vibration, heat or stiffness (yet).

 

Is there a simple way that I could clear out the bearings and re-fill them from scratch? WD40, or white spirit, or petrol? Its not something I want to take to pieces myself at this point.

 

Cheers boys!

 

 

 

are they sealed or purge bearings,any pics

[cornish wood burner]

I think that it is coming out between the cage and bearing rather than at a point in the seal.

 

I've looked up a video of the product Johnny linked, and it looks like the right sort of direction. A £100 tool that I can use again in future might be worth it if it saves me replacing bearings at the cost of parts + labour.

The cage is internal and keeps the rollers spaced and in place. Are we talking about a self aligning bearing? I presume you mean the grease is coming out between the outer race and the bearing housing which is at a larger diameter than the outside of the seal? If this is the case then your problem is a normal grease way blocked.