OT- Rubber seals for externally regreasable ball bearings?

Mower deck spindles....2 of the 3 have ball bearings with different seal types.
One has a single sided rubber seal on the top, shielded bearing on the bottom.
Other 2 have shielded bearings both top and bottom.
I'd like the replacements to have rubber seal equipped bearings both top and bottom,
single sided because there is a grease fitting on the spindle housing.....

So 2 questions:

1.
Would rubber seals be able to handle the RPM these bearings operate at?
Looking at engine RPM, deck gearbox, pulley sizes, my guess is, the blade spindles are in the
3400 - 4000 RPM range. I know they can overheat at higher than max design speeds.

2.Are rubber sealed bearings externally re-greasable?
IOW, if I pump grease in the spindle thru the grease fitting, will it just ooze past the seal,
or is the seal so stiff it might just hold the pressure till it blows out?
Remember, these will have the rubber seal only on the outside, and the inside will be open in
the housing.

I don't believe grease would penetrate the rubber seals.

I think you should check the service manual for your particular deck but my understanding (having recently read the bearing replacement instructions for a John Deere 272 grooming mower deck with a similar two-bearing per spindle set-up) is that the upper bearing was specified as unsealed so that grease pumped into the zerk fitting makes it into and through the top bearing, into the spindle housing and into the bottom bearing.

I believe the only sealed side is the bottom of the bottom bearing (so that debris doesn't work its way up into the spindle from under the deck).

But double-check the manual.

Just for reference, a double-sealed 6004-2RS (20mm bore) is good to 11K RPM, so your speed's fine. It's the issue of doing a total fill of the bearing with grease that may be a problem, as it sounds like the case when filling an open area (housing + unsealed side of bearings) to the point where you purge old grease.

Most bearings don't like full fills unless running at very low speeds, so you're at risk of overheating from the excess grease. I do think the remaining seal side would "burp" extra grease once the cavity is filled, as long as you're doing it slowly (a rapid fill might "hydraulic" the seal off).

I'm glad I took this thing apart.
Bought it used, and used it for 4 years now, knowing it needs attention. Tired of hearing-feeling the whirring from bearings, and that mysterious rumbling sound.....
Turns out the rumbling was from one of the top bearings being 1" bore, and the spindle shafts are 25mm. Monkeys have been at this thing at some point.


Per above comments, the manual doesn't contain such detailed info as type of bearing and seals.
Dumpster, by 'unsealed' you must mean shielded? On this deck, a open unsealed bearing wouldn't last long, as dust and grit would kill it quick. Plus, the zerk is much closer to the top bearing, so I think grease would come out the top, and never work its way to the bottom (which I did see evidence of with the old bearings).

OEM part number googling wasn't any help either, and I got the bearings from a bearings and drives outlet based on size and the rubber seals I wanted. I ended up googling more, and finally found info on rubber seal SFM limits....should be fine as Milland points out. (I'm hoping for 'burp-ability' with the rubber seals). No control on fill amounts, just have to hope they sling it off, or otherwise survive......fingers crossed.

Any way you cut it, (pun intended) mower deck service is a tough life for a ball bearing under less than ideal conditions.

I've been mowing for hundreds of hours without greasing the bearings (Deines mower). I did a deck rebuild quite a few years ago now, I think I went to some trouble to make a good baffle cap to keep dirt and water out and string from being able to wrap around the shaft, which is typically what takes the bearing seals out. To my way of thinking, it is better to leave the seals in the top bearing so that some grease might stay up there, otherwise it will likely get hot enough to run off to the bottom bearing. I realize I will have to rebuild the deck at some point, but it seems to have lasted long enough as is.

I'm surprised these bearings were still going for the condition they were in. The lower ones all had loose shields, and there was grit all in the cages. But only one appears to have spun on the shaft a little, not too bad tho. The bearings have blue colored grease in them.
I don't know what temp's this grease flows at. But I'm thinking if it gets hot enough to flow, there will be much greater problems happening.

The way these spindles are built (Grasshopper/Woods) the bottom
bearing is up inside the spindle casting more than an inch, with the blade hub close fitting to the bore. Shielded in effect...and pretty good protection from things that wrap around the blade and shaft.

In my experience those bearings will last seemingly forever without any maintenance until some outside source damages something. Over greasing or the wrong or contaminated grease, water from some over enthusiastic owner cleaning the deck with a nozzle, etc. I realize eventually I will have to rebuild something but have three mowers and all I do is scrape the build up out of the deck, original grease and been using them for over thirty years without a problem.
Dan

Many years ago, I rebuilt a mower deck and used non grease able ball bearings. They never lasted very long, tried several times same results. I have a Grasshopper mower as well, it uses 6205 bearings I buy shielded bearings and knock the shields off on the inside so they can grease well.
Must be a really good design because they last and are tough.