Wheel Bearings

[MC5W20]

This is in regards to spindle set ups with tapered cone bearings, not sealed units. In general we all know you tighten the nut turn the wheel, loosen the nut turn the wheel, tighten nut again and install cotter pin and retainer.

MY shop procedure calls for 17 in. lb tourque, I am using 27 in. lb. I was wondering what you guys are using? Any opinions on how much torque would be to much. When, I was taught how to do this 18 years ago I was instructed to do it like this:

Tight nut to full tight (no tourqe wrench), loosen 1/2 turn, spin wheel, then tighten 1/8 turn and reinstall pin and retainer, then I was told all spindle set-ups used that exact same procedure.

I was wondering who uses the manual or who has got other methods they use that work equally as well. Or if those who work in a shop go a little extra tight to avoid loose bearing complaints.

 

[Warstud]

I was taught to hand tighten as much as you can...then wrench tighten until there's no more rotor play...then back off enough to insert the cotter pin.

 

[zrxkawboy]

I'm sure everyone has their own methods, and many probably work fine. I tighten the nut fairly tight (with a wrench) while spinning the wheel. Then, I back off and re-tighten by hand.

 

[Kestas]

Apart from using a dial gauge, I think zrxkawboy's method is the most widely published and the most appropriate to use.

 

[FL_Rob]

To fully seated, not fully tight.Turn wheel,tighten more(as you turn)till too tight.Loosen,Do it all over again.i do it 3 or 4 times.Last turn,quit right before that,(too tight)limit.kotter key at nearest(your call).This is vague I know, its what I use based on my vehicles wieght close to 7000lbs ,so a little tighter for me is ok,for you,maybe not.

 

[another Todd]

For automotive purposes, I wrench tighten, spin the assembly to break the lube film, loosen just enough to be able to turn nut by hand, then tighten as hard as I can by hand only, no wrenches. Then install locking device without disturbing. On class 8 trucks (big bearings), 25 to 50 pounds of torque is not uncommon. Always, always use a positive locking device. Some trucks will use a double nut to lock and they can come loose. On a used class 8 dump truck I purchased about 7 years ago when starting my trucking business, one rear wheel assembly axle and all came off the truck in a turn and tumbled down a busy road, luckily hitting nothing. Inspection revealed the double nut type of locking. I removed all 8 axles from the two trucks purchased from that fleet and they were all like that, and one other was loose. Added positive locking rings and never had another problem.

 

[punisher]

Depends on the situation. When reusing hubs, I get them hand tight. On new hubs/bearings/races I get a wrench and tighten the spindle nut to about 20 ft lb, loosen, and hand tighten.

Every once in awhile you get a hub where the race is not fully seated, hence the tightening by wrench on the first go.

 

[mechtech2]

Torque wrenches and greased bearings and nuts are too iffy for me.
What is good and safe is to tighten the nut and spin the wheel a few revolutions. Just give the nut a good medium twist, not gorilla-ize it!
Then back off one flat, and insert the cotter pin. There are often TWO holes for the pin, to get a more precise line up.

Don't forget that that area will get HOT. Parts will expand and change a lot from a cold setting.

 

[doitmyself]

All of these instructions are so subjective. Terms like "full tight", "fairly tight", "medium twist, not gorilla-ize it" , and "tighten as hard as I can by hand" could be much different for a 90 pound girlie man vs. a 250 pound football player.

Is there any way to give instructions that can be used by the inexperienced without having someone there to show you?

How tight to seat the bearings....how tight the final adjustment?

Thanks!

 

[onion]

Yes, but those instructions will be specific to the application.

My own bearing adjustments will vary depending on application, but generally speaking, I'll tighten the nut pretty tight while turning the hub, back off until loose, put the nut finger tight, and lock it in place. You're generally looking for end play in the bearings to be between zero and a few thousandths. A little preload is fine (and even desirable) in some tapered roller bearing applications (particularly with an oil bath), but most wheel bearings will be fine with a measured end play between .001" and .005" (and I've seen some heavy truck hubs that allow up to .010" end play). Even though they will work fine with a small amount of preload, most bearing manufacturers recommend this small a mound of end play because it can be simply and reliably measured- whereas preload is more difficult to measure.

 

[Silk]

I just nip them up lightly,back off until I feel free play,take the free play out and that's it.I don't preload at all.

 

[SZR48207]

I think my Haynes manual says to do 18 ft-lbs. If you are at the point where you are having to put the rotor back on, you would already have an idea of what feels "normal" when you spin a wheel by hand.

 

[swalve]

I've heard that the reason for leaving them at a couple thousandths loose is so that when the metals heat up, they end up being tight with the proper amount of preload. If you make them too tight, when they heat up you get too much preload and lose efficiency and longevity.

I've only ever done rear, non drive wheels on smaller autos, and I tighten it down until the wheel spins a little hard, then back it off and set it as close to zero as I can. Never had any trouble with that. The bearings never show any wear and the wheel always spins freely nor does it develop any free play. Good enough for government work.....

 

[Bluestream]

From Timkin instructions:

"Tighten adjusting nut while rotating the wheel until the wheel binds slightly. This indicated that all parts are sealed properly. Back off nut until cotter pin can be inserted. Inset cotter pin and bend the ends around the adjusting nut. Clean the inside of the grease cap and pack with grease and tap into position."

 

[mechtech2]

Bluestream - What if there is no wheel on the car? Timkin's instructions would not work. Most adjustments are done without the wheel on.


doitmyself - Once the nut is at zero with a common tapered roller bearing system, tightening it further does not move it much.
Rotate the hub, disc, or drum while tightening it. There is no exact torque, nor can there be. If you need a number, use 20 ft lbs and back off one flat - maybe 1/2 a flat. This is for a cold system.

 

[Bluestream]

Yes, I guess you would have to put the wheel on to make the adjustment; the wheel provides the mass to do it correct. That would not take much time or effort.

 

[mechtech2]

Many wheels don't allow access to the nut.