Sealed Berrings?

[Stratoflyer]

I've recently acquired a used JD Z915B Quick Turn mower with unknown maintenance history. There's a grease zirc for each blade spindle on a 60 inch deck. I've heard via unofficial contacts (mainly, friends who've heard stories passed along by someone else) that grease zircs on blade spindles are useless since the spindle bearings are sealed and not affected by applying grease. Namely, the zircs were installed to disuade the "uninfomed" ignorant end user to not be disuaded thinking it's a poor design by virtue of not having a grease zirc to keep spindles lubricated. I'd like to know the honest truth. Are bearings sealed but manufacturers keep puttng grease zircs to disuade potential customers from buying thinking they're too dumb to accept that sealed bearings are adequet design? Anyone know the truth on this? Best...

 

[dodge man]

It’s possible but it’s the first time I’ve heard that theory.

 

[Grumpycat]

Some owners install zerk fittings on spindles.

Yes, double sided sealed bearings are commonly used on spindles which have a large volume inside, likely half your tube of grease.

You can take the spindle apart and check for yourself. Buy new bearings if you wish, cheap vs the labor to get to the old. When you are in there remove the inner seal if you wish.

IMHO the real problem is not quantity of grease or frequency of service but of the pathetic seal on the bearing at the blade being expected to keep crud out.

Motorcycle wheels use the same sealed bearings in a much tamer environment but add a much stouter outer seal. Here I put grease between this outer seal and the bearing seal so as to catch anything that gets past the outer seal.

 

[KennyG]

This has been discussed before. The bearings may be sealed but greasing the fittings keeps moisture away from the seals and cools the bearings. If it has zirks, grease it.

 

[DarkBlack]

Makes no sense to me to grease a housing that employs double shielded ball bearings..Absolutely zero sense with sealed ball bearings.
These bearings are pre-lubed from the factory. Putting external side pressure from grease on sealed bearing’s seals and shielding will only create extra friction and heat within the bearings. If you want to fill up your housing with grease, then replace your bearings with open bearings, or pop off the shields/seals.
They make open bearings for a reason…

 

[Grumpycat]

This has been discussed before. The bearings may be sealed but greasing the fittings keeps moisture away from the seals and cools the bearings. If it has zirks, grease it.

Moisture and crud enter the bearing from the blade side, not from inside the spindles.

 

[beenthere]

You can believe what you want. Up to you to believe if necessary or not. I pump a couple pumps of grease into the spindles at least once a year, and have never had a spindle bearing fail.

Best of luck with your decision.