Guidance for replacing spindle bearings on Tiger Cub

[bertsmobile1]

No information is because these jobs are done by skilled fitters who know
To remove tapered races the easiest way is to run a bead of electric weld fully around the middle of the race
When it cools the race will contract & drop out.
Again std practice in engineering workshops because doing it this way does not damage the housing
Installing is done by chilling the race & heating the housing
Workshops who do a lot of them will have CO2 pellets for the chilling because it will come out shrunk and DRY
If you put it in your freezer it must be in a sealed plastic bag with as much air as possible removed
When I do steering races on my vintage motorcycles I make a steel drift to install them with and chill the race on the drift so it haas big thermal mass so heats up slower .
I use the same set up for a few mower spindles where the bearings are a light press interfearance fit or tighter

 

[aggiejet]

No information is because these jobs are done by skilled fitters who know
To remove tapered races the easiest way is to run a bead of electric weld fully around the middle of the race
When it cools the race will contract & drop out.
Again std practice in engineering workshops because doing it this way does not damage the housing
Installing is done by chilling the race & heating the housing
Workshops who do a lot of them will have CO2 pellets for the chilling because it will come out shrunk and DRY
If you put it in your freezer it must be in a sealed plastic bag with as much air as possible removed
When I do steering races on my vintage motorcycles I make a steel drift to install them with and chill the race on the drift so it haas big thermal mass so heats up slower .
I use the same set up for a few mower spindles where the bearings are a light press interfearance fit or tighter

Well if you have to run a bead on these races to extract it there is NO WAY a mower shop is doing that to rebuild one. And in my opinion, thats a bad design/engineering to make a spindle that bearing replacement takes that level of skill and special tools.

 

[bertsmobile1]

Well if you have to run a bead on these races to extract it there is NO WAY a mower shop is doing that to rebuild one. And in my opinion, thats a bad design/engineering to make a spindle that bearing replacement takes that level of skill and special tools.

This is the difference between throw away domestic mowers & long life commercial mowers
Great Dane for instance has spindle bearings being replaced annually or at 100 Hrs which ever came first
One of the reason why mower companies switched to the wrong style of bearings ( deep groove balls ) is because they are cheaper to buy & install
On top of that every time you knock them out you take a bit of the housing out with them so after X bearing replacements it is new housing time .
A proficient shop with knowledgable mechanics would have done exactly what I suggested originally & shortened the spacer to take up the wear in the bearings then slipped in a spacer under the blade if needed to make up the difference in blade clearance .
That is the difference between a real mechanic and a parts swapper with no formal education or trade certification who are allowed to be called "technicians" which you will find in 99% of the mower shops .
Not meaning to sound rude but you seem to have little idea about what is good sound engineering practice
Good is seldom easy
And I do this regularly and I am a mower repair technician who runs a mower repair workshop for a living
If the tapers have been fitted properly then the thick end is inwards and sitting on a shoulder or retaining ring
If you want to chomp your knuckles with a hammer & punch then you get a big diameter punch, grind a long tapper on one edge so it can sit flat against the side of the housing then grind a step into the tapered edge so it can locate on the small protruding lip of the race
You can also use a long nail punch with a notch cut on the end to locate onto the race
I have even see a long cold chisel cut in a similar way
However all of these run the risk of damaging the lip that the race sits on which is why the bead of weld has been used for about as long as electric welding has been around.
In a workshop situation where the gear is there ready to use it is a 30 sec job
It takes longer to go to the corner and wheel the welder to the mower than it does to lay the bead and before you wheel the welder back you will hear the tinkle of the race hitting the floor .
And it is a lot faster then mucking around with hammers & punches

 

[Tiger Small Engine]

This is the difference between throw away domestic mowers & long life commercial mowers
Great Dane for instance has spindle bearings being replaced annually or at 100 Hrs which ever came first
One of the reason why mower companies switched to the wrong style of bearings ( deep groove balls ) is because they are cheaper to buy & install
On top of that every time you knock them out you take a bit of the housing out with them so after X bearing replacements it is new housing time .
A proficient shop with knowledgable mechanics would have done exactly what I suggested originally & shortened the spacer to take up the wear in the bearings then slipped in a spacer under the blade if needed to make up the difference in blade clearance .
That is the difference between a real mechanic and a parts swapper with no formal education or trade certification who are allowed to be called "technicians" which you will find in 99% of the mower shops .
Not meaning to sound rude but you seem to have little idea about what is good sound engineering practice
Good is seldom easy
And I do this regularly and I am a mower repair technician who runs a mower repair workshop for a living
If the tapers have been fitted properly then the thick end is inwards and sitting on a shoulder or retaining ring
If you want to chomp your knuckles with a hammer & punch then you get a big diameter punch, grind a long tapper on one edge so it can sit flat against the side of the housing then grind a step into the tapered edge so it can locate on the small protruding lip of the race
You can also use a long nail punch with a notch cut on the end to locate onto the race
I have even see a long cold chisel cut in a similar way
However all of these run the risk of damaging the lip that the race sits on which is why the bead of weld has been used for about as long as electric welding has been around.
In a workshop situation where the gear is there ready to use it is a 30 sec job
It takes longer to go to the corner and wheel the welder to the mower than it does to lay the bead and before you wheel the welder back you will hear the tinkle of the race hitting the floor .
And it is a lot faster then mucking around with hammers & punches

I am surprised your shop used to rebuild spindles (original poster). If OEM spindles cost $250 each, consider aftermarket ones. I realize you are rebuilding yours. I tried to rebuild expensive spindles on a Wright Stander I used to have and gave up, everything was seized up. Need a bearing press to get them out. Anyway, nothing wrong with swimming upstream sometimes for the challenge, experience, and cost savings.

 

[StarTech]

I only seen one of these spindle that the cup was nearly impossible to drive out. It was so worn out there was nothing to work with beside the spindle shaft itself was also damaged. I when I said nothing it was so worn that even the cast iron housing was grooved. In that case it was better to just replace the spindle with a good after market spindle. Besides at the time the spindle was only $109 retail with my cost a lot less.

A few after market are Oregon 82-325, Rotary 9153, and Stens 285-597. The best price of the three is the Oregon version.

 

[aggiejet]

This is the difference between throw away domestic mowers & long life commercial mowers
Great Dane for instance has spindle bearings being replaced annually or at 100 Hrs which ever came first
One of the reason why mower companies switched to the wrong style of bearings ( deep groove balls ) is because they are cheaper to buy & install
On top of that every time you knock them out you take a bit of the housing out with them so after X bearing replacements it is new housing time .
A proficient shop with knowledgable mechanics would have done exactly what I suggested originally & shortened the spacer to take up the wear in the bearings then slipped in a spacer under the blade if needed to make up the difference in blade clearance .
That is the difference between a real mechanic and a parts swapper with no formal education or trade certification who are allowed to be called "technicians" which you will find in 99% of the mower shops .
Not meaning to sound rude but you seem to have little idea about what is good sound engineering practice
Good is seldom easy
And I do this regularly and I am a mower repair technician who runs a mower repair workshop for a living
If the tapers have been fitted properly then the thick end is inwards and sitting on a shoulder or retaining ring
If you want to chomp your knuckles with a hammer & punch then you get a big diameter punch, grind a long tapper on one edge so it can sit flat against the side of the housing then grind a step into the tapered edge so it can locate on the small protruding lip of the race
You can also use a long nail punch with a notch cut on the end to locate onto the race
I have even see a long cold chisel cut in a similar way
However all of these run the risk of damaging the lip that the race sits on which is why the bead of weld has been used for about as long as electric welding has been around.
In a workshop situation where the gear is there ready to use it is a 30 sec job
It takes longer to go to the corner and wheel the welder to the mower than it does to lay the bead and before you wheel the welder back you will hear the tinkle of the race hitting the floor .
And it is a lot faster then mucking around with hammers & punches

Bert,

Thanks for the input. You’re right, I really don’t know zip about engineering. But Ive spent a lifetime repairing stuff, albeit I’m not a real machinist, but primarily a parts replacer. However, I replaced a plenum gasket in Dodge Ram 1500 5.9, and in the process had to replace two manifold stud bolts. That was definitely more than parts replacement. IMO, That plenum was an example of bad engineering. (A thin steel plate bolted to an aluminum manifold with improperly sized attaching screws) But I digress……

Im curious if Scag designed these spindles with the assumption that their network of dealer shops would be capable of the rebuild you describe. What you are talking about is real machining knowledge and skill and I salute you sir for having and deploying that skill. It’s bugs the crap out of me that we have become such a throw away society because of cheap parts.

That said, I’m lucky enough to have time to waste on this endeavor. I love doing stuff like this because I learn something I didn’t know, or develop a skill I didn’t have. And I got a MIG welder. My guess is I’ll end up welding the race to the hub, but I’m gonna give it a try.

Additionally, do you know the torque value for the 1 1/16” spindle nut?

Update: talked to Scag today. 150 ft/lbs is torque for spindle nut

 

[bertsmobile1]

Coming from an engineering background & working for a long time in tertiary metallurgy ( recycling & foundry ) I gained an appreciation about how much pollution is generated when you make some thing .
So yes , throw away engineering pisses me off as well as dose under speced products because the same pollution is generated and almost the same resources are used to make a junk part that will barely outlast warranty as a part that will last forever.
But those sorts of decisions are made in board rooms and directors make money from increased sales and in particular from repetitive sales of the same item because the original can not be economically repaired so until we get governments with testicles that mandate minimum life expectencies & heavily tax throw aways nothing will change till we pollute ourselves out of existance, and that day is a lot closer than most think . The EU tried it "end of life - reprocessing" mandate & taxes but those got canned , however they did bring in mandated durability indexes so EU products will have ( hidden usually ) expected operation hours till failure . Thus a shopper can see the $ 50 trimmer has a 50 hour life & the $ 100 trimmer has a 150 hour life then make an informed decision.
Add to that people are stupid, lazy , greedy & selfish and if we were not as a species humans would have died out before we crawled out of the caves & into the forests
So do I buy the Rolls Royce that will run for 200 years & has a genuine warranty forever or that Ford that will be lucky to get out of the sales room before it breaks down ?

 

[aggiejet]

I have successfully rebuilt two spindle hubs and posted videos of the process on YouTube.

1) Removing spindle belt drive pulley and hub.

2) Tear down of spindle hub

3) Installation of races, bearings, and seals

If you have any questions or critiques, I’ll try to answer them. Thanks for the feedback.

 

[bertsmobile1]

Nice videos thanks for sharing
We are compiling videos with correct information in This thread please put a link to your there so we can direct others to them .