I redid my main drive shaft(for bandsaw) a few years ago,not sure that they needed replacing but they got done anyhow. The new(and old) ones are sealed I guess,they have grease seals both sides.They are self aligning pillow block bearings,most likely made in China. On the pillow block there are grease nipples but I cannot seem to figure out if any grease actually makes it into the bearing.Most of it seems to ooze out around the selfaligning interface right below the grease nipple.Bearings are tight and smooth,show traces of grease at the seal line so as far as I know theyre ok but Id sure like to see evidence they are taking grease,forcing water out etc. Today I created a kind of spear with a flattish end to go on grease gun,hoping to slip it past seals and inject grease that way. Not very satisfactory,putting it charitably. Wonder if anyone else has encountered/solved this one?
They make a grease "needle". It has a grease fitting with a hollow needle attached to it for getting into small places. They should have them at an auto parts store. If I find a picture of one I will send it to you.
Hi Coastlogger,
Did the whole pillow block get replaced or just the bearing?
Can you back-out the grease nipple and take a look into the bearing?
Is it possible you've over-greased the bearing??
I would be reluctant to pierce the seal.
let us know what you find.
Best
DGDrls
The grease fitting is simply provided to lube the self-aligning feature. Sealed bearings are intended to run until replacement without additional grease. There are bearings that have seals which are removable, allowing the bearing to be cleaned and lubed, then the seals re-installed. These bearings can be identified by the split ring retainers that capture the seals. Regards, Clark
I found out the hard way that you can over grease a bearing. If it is a high speed bearing it will only stand so much grease.
Coasty, if the bearings you took out are the same twist the bearing insert like you were going to remove it if theirs a groove all the way around and a hole going in to the bearing grease will enter. Sometimes narrow grease channels will get plugged with hard grease and its hard to pump in. Sometimes you can carefully lift a bearings little rubber skirt and peek inside to check for grease and even pump more in using a needle greaser or whats commonly called a cats #rick. Frank C.
As Clark said, the grease fitting on an inexpensive self-aligning pillow block isn't there to grease the bearing. It's simply a way to squeeze some grease between the bearing and the pillow block.
It's not a particularly useful feature because it's DanG near impossible to force grease into that space.
Im not positive but reasonably sure that there is a groove on these bearings to allow grease to go to the brg. Cannot check that without a full dismantling which Im not yet ready to do.I kept the old brgs and they have the channel(s) but of course new ones are a different brand I think.
Brucer on these brgs the grease quite readily comes out around the self aligning joint.
Guess Ill monitor noise and temp like suggested and needle some grease in behind seal every once in awhile. Good info as usual.,thanks!
I remember some pillow block bearings back on the farm that were put in wrong (the bearing installed wrong into the pillow block). We'd try to grease and it was hard to pump and after a pump or two grease would come out around the seal. Come to find out the bearing itself had just the one hole and no grease channel or groove inside the pillow block to carry the grease around and into the bearing. That bearing hole had to be lined up with the grease fitting in order to get grease into the bearing itself.
On my roller guides I drill a little hole in the seal and give the bearings a couple of pumps every day with a needle nose grease gun, my bearings last for years instead of months with no grease. Steve