Front Wheel Bearing Preload - Do It Right!

I just pulled the front right side hub off my CJ5 to upgrade the brakes to 11".
Finishing up an upgrade to 11" brakes all four wheels on my CJ5 the last one being the right side front.
On the driver side front I found that two of the spindle bolts had been overtightened at some point and stripped. The stripped threads had been "repaired" with Helicoil inserts. Not my favorite fix, but will do for now until I find another knuckle, or convert to studs, but these will hold at 35lbs.

On the right front hub I had a devil of a time getting the hub off the spindle. Whomever serviced the Jeep years ago had over tightened the spindle nut causing the inner bearing to heat enough the inner race was practically welded to the spindle. After about an hour with a serious slide hammer and other tools I finally got the hub to pull free leaving the seal (melted) and bearing attached to the spindle.

I encountered the same thing on a Model A Ford when I was a kid and I had to cut the bearing off and polish the spindle because I didn't have a spare one. At that time my father explained what had happened and showed me his method of setting the bearing preload by feel.

In this case I had a good spare spindle, so I tossed the burnt one, and replaced it.

That experience with the Ford taught me something, so I decided it might save somone some grief if I describe how I set the bearings. It is important to do this the right way and while others may have a different method this works for me.

This is how I do it, and while it is close to what is in the TSM I usually have to tweak the suggested 1/6th turn and go just a bit more.

1) When a front bearing is serviced whether just repacking with grease or replacing the bearing it always needs to go back with a new seal.
2) With the inner and outer bearings packed and assembled in the hub the hub is placed on the spindle and the smaller washer in the service pack goes on, then the spindle nut should be tightened until resistance is felt on when turning the hub. I usually torque to 50 lbs to make sure the bearings are seated then back off just a bit where the hub will turn with some resistance and no play.
3) This is the important part! Once the bearings are seated the nut needs to be backed off approximately 1/6 of a turn which is the distance between two of the drive flange bolts. You should be able to feel just a bit of play when you push and pull on the hub.
4) Then the bigger washer and lock nut are installed, but before bending the washer onto the nut check to make sure you still have that bit of play. I have sometimes found that installing the lock nut and washer will cause it to tighten up a bit. If no play is detected, remove the lock nut and washer and back off the spindle nut just a little more.

If the bearings are too tight they will burn, if too loose they will get hammered, but a tiny bit too loose is preferable to being even a tiny bit too tight.

 

Boy have I seen this go wrong so many times.. Especially on trailers..

 

definitely saving this for whenever i need to do this.

 

Like I said, it is pretty much what is described in the service manual, I just thought some with less experience might not understand that 1/6" turn is sort of just a starting point. I used new bearings, but when old bearings are good enough to reuse they need to be soaked in solvent, brushed and blown out with compressed air but don't spin them with the air, blow out the old grease from top to bottom, then repack them with good bearing grease. If you don't have one of those bearing packing cups I highly recommend getting one.

It was close to 100 degrees out there today, very humid and not a breeze stirring. Tools got so hot I couldn't hold onto them. That is what living in the "Sunny South" is about in July, but I finished the brake upgrade with frequent trips back into the air conditioning to cool off.

Tomorrow I plan to be juicing them up for bleeding, and installing the drive shafts with new universal joints. Then this Jeep will be ready for a road test! It will be the first time it has moved under its own power since 1979.

It has new bearings and seals all around plus 11" brakes on all four wheels. Everything in the brake system, and fuel system is either new or rebuilt.

Once I get it moving I can drive it into the shop for the rest of the work. Shop is air conditioned, I just didn't want to have it in there until I could move it out when needed. I have other things to work on.

Going to spend the rest of the evening floating around in the pool sipping cold beverages until the stars come out.

 

Since '79! Wow. This is quite an accomplishment then. Glad that you're getting it done. I've used one of those cheap pop up canopies for protection from the sun, in the past. Sure helped.

 

I had a patio umbrella out there that helped a bunch, but it was still dreadfully hot.

Just came in from the pool, too cloudy for stars, but it was nice watching the fish swim around in the waterfall. My wife built a beautiful garden around the pool and that water feature was my contribution, and it is relaxing to watch it. The fish have bred this Summer and we saw at least four baby fish.

Yes, bringing something back from that far away is a rewarding thing for me. The Jeep had been parked back then because it was using oil, but it only has 33K miles on it so I figured it was stuck rings. It smoked like a freight train when I first got it running but I used Marvel Mystery oil in it and it is now running pretty good, only smoking a little black smoke due to running a little rich. I think this is just something with the main jet or metering rod.