Going through mowing deck bearings

[MattA]

I'm going through mowing deck bearings in probably less than 100 hours of mowing time in my RM48 deck. I rebuilt the deck with new blades, new belts (drive and internal), steel spindles (with grease fittings), new Ingersoll bearings, new bearing spacers, new bearing dust shields and new hardware. I don't know off hand if I replaced the top spindle spacer (page 16 item #9 in the 8-3073 parts manual, part number C29431). I also replaced the idler pulley and pivot spacer for the idler bracket. Bearings were inserted gently using a socket approximately the same outer diameter as the bearings and tapping gently with a 5lb hammer. Spindles greased with my grease gun. This lasted me two mowing seasons.

When I pulled out the deck which had been stored in my garage over the winter (spring 2020), the center spindle was seized. I was able to break it loose and it made a horrible grinding noise afterwards. I just assumed water had gotten in the bearings and rusted since I hosed the deck off and stored it. I ended up replacing all six spindle bearings with new Ingersoll bearings. I also replaced the the center spindle assembly with a new one from an RM38 deck (slightly faster blade tip speed). My old RM48 center spindle was shot and chewing up belts. I also replaced the belts. The last part giving me trouble is the pivot spacer for the belt tensioner (page 13 #21 PN: C14768). I grease this pivot spacer seasonally and it always seems to wear out and seize to the washer under the tensioner bracket. Toward the end of 2020 mowing season I thought the deck was slowly getting louder. I typically mow with my hydravac and 3M ear protection.

So hear we are in 2021. This spring the idler bracket pivot bushing was again seized to the washer below. This time I drilled out the bracket hole and installed a larger new bushing left over from the mule drive rebuild (2016). The bearings in my mowing deck seem to slowly keep getting louder. Last week I mowed without the hydravac and I could definitely hear the issue without the added hydravac noise. I pulled off the belts and the chute side bearings were quite noisy. This weekend I replaced both bearings in the chute side spindle with a pair of good tight bearings I saved from last springs rebuild. I greased all spindles, installed new bolts/lock washers all torqued to 35ft-lbs, and sharpened all blades. Blade balance seems good. The center spindle bearings are starting to make a little noise but not too loud. The idler pulley bearings are also starting to make some noise (bearing seems a little loose). The deck is much quieter now.

I'm tired of rebuilding this deck. I've got maybe 175 hours on it at this point. Am I doing something wrong?

[Eugen]

That must be frustrating. I personally don't have any experience with this as I mow very little and never replaced the bearings that my two decks came with. I don't think that the occasional hosing would be the culprit though. It should be hard for water to get in from just hosing the deck off. Now if you use a pressure washer, that's a different story.

Does the original bearing have a proper seal behind that metal side cover?

[MattA]

That must be frustrating. I personally don't have any experience with this as I mow very little and never replaced the bearings that my two decks came with. I don't think that the occasional hosing would be the culprit though. It should be hard for water to get in from just hosing the deck off. Now if you use a pressure washer, that's a different story.

Does the original bearing have a proper seal behind that metal side cover?

No pressure washing the deck...

Never thought of taking the bearings to see if the internal seals are intact. I did read on the old forum that it might be possible to blow the seals out with pressure created by the grease gun.

What are you guys using for a grease and grease gun?

[Timj]

I don't have a good answer for you, Matt. Bad luck? Don't build them like they use to?

Unless the dealership changed them in my AHRM48 years ago under the TOP warranty program, I'm pretty sure mine are the original ones. Probably pushing 1000 hours, not noisy.

I give mine a couple of pumps of a red moly lith high speed grease when I change/sharpen blades.

I have an expensive bearing in my drill rig that's less than a year old that's failing. It's probably going to take three days to change it out. The old one was 45 years old. Wasn't crazy noisy but while I was rebuilding the shaft we replaced everything. The old one would have outlasted me, should have left it I guess.
I feel your frustration.
Tim

[Gordy]

Matt,
I have yet to see a spindle housing that is sealed tight, let enough tight enough to blow a seal from a bearing.


Gordy

[Eugen]

No pressure washing the deck...

Never thought of taking the bearings to see if the internal seals are intact. I did read on the old forum that it might be possible to blow the seals out with pressure created by the grease gun.

What are you guys using for a grease and grease gun?

I don't think mine has zerks so no extra grease from me those bearings gotta survive on their own or not at all.

I'm really tempted to order the cheapest bearings with just 2RST seal I can find. If I'm going to change them often anyway...

[MattA]

The original Ingersoll packaged I bought said Fafnir on them (Timken). I recall the 2nd set of Ingersoll packaged bearings I bought were marked "China".

I changed the chute side spindle bearings without removing the deck. Quick and easy. Front of the tractor was up on ramps with the ramp pointed away from the tractor (I jacked the tractor up and slid the ramps under the front tires).

[MattA]

I don't think mine has zerks so no extra grease from me those bearings gotta survive on their own or not at all.

I'm really tempted to order the cheapest bearings with just 2RST seal I can find. If I'm going to change them often anyway...

Not all steel spindles had grease fittings. Hopefully you don't have the aluminum spindles.
You can still grease your spindles manually with the spindle shafts out. I haven't had to try this but should work in theory.

[MattA]

I've sharpened my blades several times this year to get better cutting performance. I found I wasn't making the blades sharp enough and the tips of my grass blades sometimes looked slightly torn and frayed. I ended up doing some research to find out the ideal blade sharpening angle is about 30° and I failed at finding an inexpensive tool to measure the blade sharpened angle.

I ended up measuring a new blade I had laying around with a caliper and doing some trigonometry. The blade thickness was 0.200” and the length of the sharpened edge was about 0.340”. Taking the inverse sine of 200/340 comes up with 36°. No need to have a scientific calculator, you can put “inverse sine (200/340) in degrees” into googles search function and it will spit out 36°. If you wanted to target 30°, the length of the sharpened edge needs to be increased to 0.400”.

Balancing the RM series blades requires a bit of guess work with one of those $7 plastic balancers due to the blade having a “DD” mounting hole instead of a round hole. You have to guess at the center of the DD hole. I searched the internet for a while to find a blade adapter that I once saw posted on the old forum. I bought the adapter and it does not fit on my $7 plastic balancer. The hole size is something odd like 0.560”. To make matters worse, the adapter does not fit in my blades DD hole (new or used blades) The adapter is a few thousandths larger than the blade hole.

Link to RM series blade adapter:
https://www.magna-matic-direct.com/prod ... tsman.html

Anyways I've got my blades balanced and sharpened to 30°. Not sure its going to make much of a difference. I'll have to wait for this weekend to try out the sharpened blades and quieter bearings.

[Gordy]

Not all steel spindles had grease fittings. Hopefully you don't have the aluminum spindles.
You can still grease your spindles manually with the spindle shafts out. I haven't had to try this but should work in theory.

That sounds like a PITA, it is so easy to drill and tap a hole and screw in a zerk.


Gordy