Spindle problems - 317 48" deck

[Rex B]

I am rebuilding the mower deck on my 1864.
I have replaced all the bearings and seals in each of the 3 spindles.

Timken Set2 bearings (11910/11949)
Timken 471737 seals

All three are back together now, but 2 of them are very tight - hard to turn by hand. I did install the center spacer between the bearing cones. All the races are seated fully in their bores.

Is this normal, and will they loosen up after they run a bit?
Or should I disassemble and shim the bearings out a bit so they turn free?

[J-Mech]

Well, I can't feel them from here... LOL. But I would say shim them up. They should be snug, but not tight.

[CADplans]

Originally Posted by J-Mech

Well, I can't feel them from here... LOL. But I would say shim them up. They should be snug, but not tight.

I would think tapered roller bearings should not even be run snug. They need room for grease.

As a youth, I saw MANY bearing failures on shade tree mechanics cars where they "snugged" the front wheel bearing.
(They were always taking the bearing apart to replace the drum brake shoes, )

Car bearings run "somewhat" slower than spindles.

I think you also need some "slop" for thermal expansion!!

[J-Mech]

Originally Posted by CADplans

I would think tapered roller bearings should not even be run snug. They need room for grease.

As a youth, I saw MANY bearing failures on shade tree mechanics cars where they "snugged" the front wheel bearing.
(They were always taking the bearing apart to replace the drum brake shoes, )

Car bearings run "somewhat" slower than spindles.

I think you also need some "slop" for thermal expansion!!

Yes, you are correct. They don't need to be tight, and they do need room for thermal expansion, but not for grease. The grease will fill the void between the rollers where the cage keeps them separated. You also don't want them loose. The bearings need to be "snug" and have no play in them, otherwise they will wear poorly. At the high speed of a spindle, the shaft can deflect, or vibrate the bearing in the race and cause premature bearing failure. The new bearings must not be tight, but they must not be loose either. I don't know how to explain the feel of a bearing set properly. And the book doesn't specify. Just take all the "play" out of them and you should be ok.

[CADplans]

Originally Posted by J-Mech

Yes, you are correct. They don't need to be tight, and they do need room for thermal expansion, but not for grease. The grease will fill the void between the rollers where the cage keeps them separated. You also don't want them loose. The bearings need to be "snug" and have no play in them, otherwise they will wear poorly. At the high speed of a spindle, the shaft can deflect, or vibrate the bearing in the race and cause premature bearing failure. The new bearings must not be tight, but they must not be loose either. I don't know how to explain the feel of a bearing set properly. And the book doesn't specify. Just take all the "play" out of them and you should be ok.

The correct tightness is almost a lost art!! On a car they used to give a torque for the castle nut. Hopefully, it was enough to remove the play and grease. It was not much torque.

THEN, you backed it off, IIRC, it was one flat of the castle nut.

With about 20 threads per inch (?) that would equate to 0.008".

Maybe too much for a spindle, , but perfect for a front wheel of a car.

If it is too tight, the bearing will be happy to spall.
http://en.wikipedia.org/wiki/Spall

[J-Mech]

Originally Posted by CADplans

The correct tightness is almost a lost art!! On a car they used to give a torque for the castle nut. Hopefully, it was enough to remove the play and grease. It was not much torque.

THEN, you backed it off, IIRC, it was one flat of the castle nut.

With about 20 threads per inch (?) that would equate to 0.008".

Maybe too much for a spindle, , but perfect for a front wheel of a car.

If it is too tight, the bearing will be happy to spall.
http://en.wikipedia.org/wiki/Spall

Yes, you are correct!!! Sometimes it's hard for me to explain things that I do everyday without thinking.... I just do it. This is a great explanation! You should tighten them, then back them off. On differential pinions, some use a crush sleeve, some use shims. (The pinion shaft is attached to the drive shaft.) It turns, in overdrive with an engine RPM of 3000, approx 4500 RPM. (not exact figures, and based on a .67-1 overdrive ratio and a 3.73-1 ring and pinion. At this RPM the truck would be at approx 80 mph) Anyway, we set the pinions to a rolling torque of 15-25 Inch pounds. (this is a general setting) If I remember correctly spindle speed is approx 3000 RPM?... So this maybe is a better method. But lets lower the setting a bit, just because a pinion runs in oil, and the spindle runs in grease. So it may tend to heat up more. Lets set it to 5-15 InLbs.

So, if I was to start over, I would say... Put the new bearings in, and without a spacer tighten them down until you feel them drag. This will "seat" the bearings. Back the nut back off. Install the spacer and guess on the amount of shimms. Then tighten the nut up against the bushing and added shims, then put an inch pound torque wrench on the nut with it set to about 10 In Lbs. (That would be the middle point on the specification of 5-15 InLbs. If you don't have an inch pound torque wrench, you can rent one from an auto parts store.) If it's too tight, add shims. If it's too loose, remove them. Do this until the torque it takes to turn the shaft gets within the spec. Every time you add or delete shims, roll the shaft several times before you take a reading. Also, put oil on the bearings. DO NOT do this dry, it will throw off the measurement. This method should get you really close to original.


Is that a better way to explain how to set them properly? I guess I wasn't really very detailed or in depth the first time. And by feel really wasn't an answer was it

Good Luck!!

[CADplans]

When I worked at GE, we found the typical male worker could turn a nut-driver to very close to 10 in-lbs, almost EVERY time.

So, if you have no torque wrench, maybe a nut driver and a BUNCH of adapters to get 1/4" drive up to the socket size would be closer than nothing!!

[Rex B]

Decades of messing with cars leaves me with a pretty good feel for how tight a bearing should be. Of course there is no castle nut or other provision for backing off, though I have considered red loctite. Safety wire is also something I considered.
Good to know there is a spec, thanks for that.

I think I am going to find some .75 ID shims and get this right. I think as long as it's down I'll get some 1.25" stock and make up some new seal bushings. Mine were too rough for me taste.

Am I the first one to run into this?

Thanks for the input.