seal choice and bearing preload.

[Keith S]

Rear wheel bearing adjustment procedure as stated in Mack's Wheel Bearing document:

1. Preload: Torque adjusting nut (while turning wheel) to 250 lb.ft
2. Loosen adjusting nut 1 full turn
3. Torque adjusting nut (while turning wheel) to 50 lb.ft
4. Loosen adjusting nut as needed to align the adjusting-nut pin with a hole with anti-rotate thing
5. Install outer nut & torque to 300-400 lb.ft

[h67st]

On 3/9/2018 at 4:18 PM, Vladislav said:

What kind of hub bearings preload are you talking about guys? There's no preload, there's slack.

Slack in the bearings will cause excessive wear and vibration...you want them snug as shown in Keith S's procedure.

[theakerstwo]

On most taper brgs you will find that the inter race turns some thru its life.This is something that lets the brg last longer.On a eaton trans the counter brgs are a slip fit when new just like on a axle.

[Vladislav]

6 hours ago, h67st said:

Slack in the bearings will cause excessive wear and vibration...you want them snug as shown in Keith S's procedure.

3.Torque adjusting nut (while turning wheel) to 50 lb.ft

4.Loosen adjusting nut as needed to align the adjusting-nut pin with a hole with anti-rotate thing

When loosening the adjusting the nut at the last step you get the bearings free a little bit. For hub bearings that snug is used to compensate a parts heat "biggereizening". And this is typical for hub bearings mostly, probably because they have high spinning speeds or cool up less efficient than gearbox or differential ones having no such extensive oil circulation. I can't tell the reason for sure right at the moment.

Bearings you fit with preload is alomost another story when assembling. First of all you must have a distant tube to put between the inner races to stop the outer bearing from going in. You need to put a load (the preload) on it so it shouldn't be movable inwards. The tube could be of a hard desingn and you grind it into the size or add shims to make longer when setting preload. Or it could be deformable (usually on cars) so you're torqueing up the nut until a sertain number of lbsft to deform it sufficient to get a correct preload. This style of a bearing unit is usually utilized in carrier pinion assembly. And you don't need a lock nut in those cases since you torque the (only) nut up to stopping against the outer bearing inner race. Which itself stops against the distance tube, which stops to the inner bearing inner race and than to the sfaft's step you put the inner bearing up to when installing. So you tight up the nut really hard with no need to lock it additionally. Just secure with a wire or a stich press from vibration.

Slack bearings fit is another story. You put the ajusting (1st) nut slightly loosy (turning it back for a couple of washer notches for example). This way the nut has no lock from turning off. So the 2nd (lock) nut is applied. Or the 1st one could be made a way to be lockable itself. For example it could be made with a split and a lock screw to tighten it up over the shaft.

[h67st]

16 hours ago, Vladislav said:

3.Torque adjusting nut (while turning wheel) to 50 lb.ft

4.Loosen adjusting nut as needed to align the adjusting-nut pin with a hole with anti-rotate thing

When loosening the adjusting the nut at the last step you get the bearings free a little bit. For hub bearings that snug is used to compensate a parts heat "biggereizening". And this is typical for hub bearings mostly, probably because they have high spinning speeds or cool up less efficient than gearbox or differential ones having no such extensive oil circulation. I can't tell the reason for sure right at the moment.

Bearings you fit with preload is alomost another story when assembling. First of all you must have a distant tube to put between the inner races to stop the outer bearing from going in. You need to put a load (the preload) on it so it shouldn't be movable inwards. The tube could be of a hard desingn and you grind it into the size or add shims to make longer when setting preload. Or it could be deformable (usually on cars) so you're torqueing up the nut until a sertain number of lbsft to deform it sufficient to get a correct preload. This style of a bearing unit is usually utilized in carrier pinion assembly. And you don't need a lock nut in those cases since you torque the (only) nut up to stopping against the outer bearing inner race. Which itself stops against the distance tube, which stops to the inner bearing inner race and than to the sfaft's step you put the inner bearing up to when installing. So you tight up the nut really hard with no need to lock it additionally. Just secure with a wire or a stich press from vibration.

Slack bearings fit is another story. You put the ajusting (1st) nut slightly loosy (turning it back for a couple of washer notches for example). This way the nut has no lock from turning off. So the 2nd (lock) nut is applied. Or the 1st one could be made a way to be lockable itself. For example it could be made with a split and a lock screw to tighten it up over the shaft.

As you show in step 3, torque to 50 lb. ft. and back off until the lock ring will slide on. After you torque the locknut, there is preload on the bearing.