# Impeller shaft Bearing (oil bushing) Retrofit ???



## tpenfield (Feb 24, 2015)

Greetings, 

I have noticed that even after a couple of years, the impeller bearing on my Toro PS 824 has some 'play' in it . . . about 0.050", I'd say, which gives noticeable movement if I pull upward on the impeller shaft.

When new it had no play in it. This leads me to believe that the bearing may only go for a few more years before needing a replacement. I have the impeller 'mod' on this machine, which really requires the bearing to last and have very little play, else the rubber paddles of the impeller blades will tend to interfere with the upper portion of the impeller housing during use.

I do try to get some oil into the bearing annually, but it still seems to wear.

My thinking is that a true roller bearing would be best, since it operates less friction than a bushing. *I am wondering if anyone has tried to retrofit a roller bearing into the 'cup' that holds the bushing? *

I might try such a thing during the off-season, if I can find a suitable roller bearing.


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## Hec In Omaha (Jan 10, 2021)

Shaw351 modified a Toro 1028 using Ariens roller bearings. 









Toro impeller bushing modification


Hello All..... I know I'm an Ariens guy...... But..... I was servicing a toro 10/28 machine for a friend, came across the old worn out impeller bushing issue that all owners have or will address on thier toro. I didnt find a thread here about replacing the OE design with a bearing, so I...




www.snowblowerforum.com





Hec


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## cpchriste (Jan 19, 2014)

Here's another approach as well
www.snowblowerforum.com/threads/toro-powershift-1332-auger-belt-auger-pulley-bearing.156717/


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## tpenfield (Feb 24, 2015)

cpchriste said:


> Here's another approach as well
> www.snowblowerforum.com/threads/toro-powershift-1332-auger-belt-auger-pulley-bearing.156717/


Yes, a grease fitting . . . that would be better than the OEM setup.

I was thinking maybe something like this . . .











It is a ball bearing with a flange similar to the Toro bushing retainer. They are $20 ish. The ID is 7/8" and the bolt pattern is 3" diameter. I'll have to check my machine at some point to see how close a match it would be.


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## cpchriste (Jan 19, 2014)

tpenfield said:


> I was thinking maybe something like this . . .
> It is a ball bearing with a flange similar to the Toro bushing retainer.


I have questions - but no answers. 
The other (Shaw351) referenced thread is full of speculation regarding whether the bushing or the pulley restricts the impeller shaft forward/rearward motion. I speculate it could be the auger gearcase thrust bearings that handle that motion. 
My point in bringing this up is that the bearing you showed for an example has set screws locking the inner race to the shaft. These set screws would supercede whatever was the original thrust load path and the screw contact points would likely work loose in service. Once loose, the steel inner race would "walk" around the shaft and wear it down.
Perhaps the loosey-goosey original bushing arrangement had the hidden purpose of allowing the impeller shaft to move so that the gearcase (and/or the pulley inner hub) transmits the impeller shaft forward/rearward loads.


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## classiccat (Mar 1, 2014)

cpchriste said:


> I have questions - but no answers.
> The other (Shaw351) referenced thread is full of speculation regarding whether the bushing or the pulley restricts the impeller shaft forward/rearward motion. I speculate it could be the auger gearcase thrust bearings that handle that motion.
> My point in bringing this up is that the bearing you showed for an example has set screws locking the inner race to the shaft. These set screws would supercede whatever was the original thrust load path and the screw contact points would likely work loose in service. Once loose, the steel inner race would "walk" around the shaft and wear it down.
> Perhaps the loosey-goosey original bushing arrangement had the hidden purpose of allowing the impeller shaft to move so that the gearcase (and/or the pulley inner hub) transmits the impeller shaft forward/rearward loads.


A keyed-shaft / inner bearing race (with set screws) would've been better (like the impeller pulley)...otherwise if that bearing seizes, bad things happen to that soft impeller shaft.


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## paulm12 (May 22, 2015)

one of the repair issues I don't see mentioned much is the following instruction from the Toro 2-stage drive systems manual (cut and pasted, not complete):

All self-aligning bearings (sometimes called the
flange bearings) MUST be installed loosely. All
models have one next to the auger drive pulley
and some use 2 more supporting the auger output
shafts. In all cases, these bearings must be a little
loose to assure the bearing can align itself with the
shaft before it is secured (Figure 19).

All models: Rotate the impeller back and forth.
One direction will push the impeller shaft to the
rear. Rotate it in that direction to force the shaft as
far to the rear as possible (Figure 21).

Secure the 4 cap screws on the self-aligning
bearing. Install the thrust washer and key.

I'm not sure how much this plays into overall wear on this bearing, but it is worth noting, and is something that I follow if I remove the impeller bearing. The complete manual is posted to the top of the Toro-specific forum. 

tx


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## asavage (Dec 20, 2021)

tpenfield said:


> I was thinking maybe something like this . . .
> It is a ball bearing with a flange similar to the Toro bushing retainer. They are $20 ish. The ID is 7/8" and the bolt pattern is 3" diameter.












The bearing you show above ^^^ is what Toro used to use in the older rigs like my 1985 38150; later, they changed to the oilite bushing. See Toro 251-224 aka trade number SB205-14. I don't know why Toro went to the bushing over the earlier roller bearing, but I do know that, like CC's picture above, mine also came loose from the impeller shaft and wore the shaft badly.

As an experiment, I've procured one of these 7/8" Three Bolt Flange Bearing SBTRD205-14G, $14:










It's greaseable and has a 3" bolt circle, which I think is just a bit smaller than the Toro's but close enough I can oval the carriage bolt holes. I'll know more when it's in my hands next week. For $14, I thought it worth investigating.

Like 140278, if this can reasonably be made to fit in place of Toro's version that self-aligns using the flange plates, then I'd dedicate a grease gun with a pipe extension so I could reach down behind the impeller sheave to grease it.

Roller bearings aren't ideal for large axial loads, but then neither is the bushing that Toro replaced their roller bearing design with, so while I'd really rather have a real taper roller bearing here, there's only so much reengineering I'm willing to do for what is essentially a hobby project.

This greaseable 3-bolt flange bearing has one significant downside as a replacement for Toro's: it won't self-align. Depending on the amount of misalignment, it might have an unacceptable wear rate even if supplied with quality grease frequently. But I still want to trial fit it and see just how badly the bearing is loaded when the auger gearcase is bolted up to the frame.


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## asavage (Dec 20, 2021)

Looks like the bolt circle on the old Toro's impeller bearing flanges _are_ 3". Good match.



























^^^ The zerk points the wrong way -- and it's slightly "below grade" -- not a straight alignment with a grease coupler even if it pointed @ 12 o'clock. Fortunately, the fix is just plumbing.

Std. 1/4"-28 taper thread for small zerks:










Picking one website that caters to this sort of thing: Grease Fitting Relocation Kit



















$16 for this setup with a 12" hose length.

I want to bring the zerk to outside the belts area, so . . . Midlands Bulkhead Fitting 28300SS, $24, which is 1/8" NPTF on both ends. I was going to buy this one, but accidentally bought a carbon steel one that has over $23 of shipping/fee added (my fault for missing that), but the part I bought is the same as the Midlands one, except not SS.

[later: the Midlands fitting is _much_ nicer that the carbon steel one; I was disappointed with the latter and later purchased the former to install.]










There are loads of _brass_ 1/8" NPT bulkhead connectors available, but the pressure that a grease gun can push fighting a clogged or damaged bearing is well in excess of what a brass fitting can handle, so this is not the correct place for brass -- unless you know for certain you'll never ever have to push grease hard.

Burst grease fittings are messy.


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## dcinma (Dec 13, 2017)

Great re-engineering!


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## cpchriste (Jan 19, 2014)

asavage said:


> This greaseable 3-bolt flange bearing has one significant downside as a replacement for Toro's: it won't self-align. Depending on the amount of misalignment, it might have an unacceptable wear rate even if supplied with quality grease frequently. But I still want to trial fit it and see just how badly the bearing is loaded when the auger gearcase is bolted up to the frame.


Probably more important than bearing stress would be the cyclic forces on the set screws tending to make them loosen, after which the bearing race will scrub the shaft. How will you measure the installed misalignment? How will you judge what value is acceptable?


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## asavage (Dec 20, 2021)

We know that the original Toro ball bearing design commonly led to the bearing's inner race spinning on the soft impeller shaft



















[ref: ClassicCat's 1987 38150 thread.]

I don't see that replacing the non-greaseable ball bearing with a greaseable one (that does not self-align) impacts that issue: if the bearing begins to fight rotation, there will be a tendency for the bearing's inner race to become unaffixed to the shaft. CC's approach to improve the situation, by providing divots in the shaft to give the set screws more purchase, seems a good idea that I will copy, but the base problem is that the bearing should not cease being a bearing and should not provide resistance to turning, which is what set screws are not good at resisting 

The OEM set screws are cup point; I'll be replacing them with conical point on the assumption that will work a bit better in conjunction with shaft divots.











While bushings (plain bearings) in general work well for certain engineering situations, high surface speed _and_ high side loads _and_ sparse lubrication are a bad combination for bushings; Oilite is a nice idea but IMO is a value-engineered method best used in relatively disposable appliances. Where plain bearings have a clear advantage is where noise is a factor (say, air handlers), as plain bearings have traditionally been a lot quieter than bearings with moving elements. In this kind of application, in the past oiler cups were provided so that periodic lubrication could be performed. Mfgrs learned that mostly this relubrication wasn't being done, and that people got used to paying the price of skipping maintenance by replacing the appliance prematurely, so the mfgrs decided, why bother making the plain bearings relubricatable?

On these older blowers, Toro later discarded the ball bearing impeller design for a Oilite bushing. That moved the bearing surface from hardened pieces to the soft shaft, but the bushing is even softer, so I assume that the majority of the wear occurs in the bushing and not the shaft on the newer-than-mine models, even as the actual life of the bushing may be shorter than the ball bearing it replaced. The actual cost of repair is lower, as the shaft never (?) needs replacement, only the cheap bushing.

A reasonable case could be made that field replacement of the older ball bearing with the newer bushing -- supplanted by a zerk ala 140278 -- could be considered an upgrade: self-aligning, re-greaseable, and cheap to replace. I just don't like bushings for this application ("high" speed, "high" load, soft shaft) and therefore I'm not considering that as an option for this particular unit.

Set screw mounting/retaining of ball bearings to shafts has been a Best Practice for over a hundred years. I'm reasonably confident that set screws can retain a ball bearing's inner race to a mild steel shaft, if the bearing isn't fighting the effort by being worn, contaminated, or siezed. Toro's original design didn't allow flushing the bearing of contaminants, and its location and environment made it a poor choice for a "sealed for life" ball bearing.



cpchriste said:


> How will you measure the installed misalignment? How will you judge what value is acceptable?


Commensurate with the overall mission, I will incorporate no measurement procedures involving equipment not found in a typical barn, in order to ascertain the installed misalignment. As to weighing suitability of any misalignment found . . . it'll be my personal judgement call, right? Sure, there are specifications that can be called upon, and tedious jigs and tools could be brought to bear on documenting the exact nature and magnitude of Toro's steel forming and weldment tolerances -- for that is what will determine how non-square the auger outer bushings are with respect to the impeller bearing's mount -- but what would be the fun of that?

I bring five careers' worth of experience to this endeavor; I have witnessed and made mine own misteaks and have a fine feel for what can be "gotten away with".


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## asavage (Dec 20, 2021)

The carbon steel bulkhead fitting I received is awful; I ordered the Midlands one, and it’s much nicer.


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