Wheel Bearings

[Jaime]

Hello

 

I plan on changing my front wheel bearings on my 88 long bed 4.0 with 4 wheel drive. Looking at the FMS it looks straight forward. What I need to know is if I need any special tools or a press to accomplish this.

 

Thanks

[Garvin]

It's fairly straight forward. The hardest part is getting the hub off.

 

You will need a nice sized hammer and flat punch (screw drivers work, not as well though), or an air hammer, to make life easy when wedging the hub out of the spindle.

 

Since I was running wheel adapters adn 36" tires on my Cherokee while the front axle was getting built up (wanted to keep with matching rims so I only needed one spare), I was going through a few hubs a year. With it basically broken loose, I was doing a side in about 20 mins with air tools.

 

If I remember right, you will need:

18 or 19mm socket (for lug nuts)

12mm wrench (for caliper bolts)

15mm wrench or socket (for caliper bracket bolts)

13mm 12pt wrench (for hub bolts)

30mm socket (for axle nut)

Chisel

Hammer

[Jaime]

Thank You for the info. Is there any brand I should use. I plan on getting them from O'Rielys.

[Geonovast]

You don't need to remove the caliper bracket.

 

Also, if there's any reason to think that U-joint might be on its last legs, now is the time to change it. That 30mm nut is a PITA, and changing the U-joint with the bearing attached to the shaft isn't fun.

[Jaime]

Thank You for all the info. I will make sure to pay close attention to the U joints.

 

Thanks

Jaime

[Garvin]

You don't need to remove the caliper bracket.

 

Also, if there's any reason to think that U-joint might be on its last legs, now is the time to change it. That 30mm nut is a PITA, and changing the U-joint with the bearing attached to the shaft isn't fun.

 

Thanks for clearing that up. It's been about a year or so since I did one and couldn't remember exactly if you had to or not, I just included it just in case.

[mvusse]

The spindle nut is 36mm, not 30. I have broken many a breaker bar on those before getting an electric impact.

 

Forget the hammer and chisel. Use your power steering as a hydraulic press:

http://www.stu-offroad.com/axle/unitbearing/unitbearing-1.htm

[Garvin]

30mm sounded a bit small for that, knew it was one of those two. The driveshaft yoke nuts are 30mm then.

 

That works but I'm not too much of a fan of putting that kind of strain on the outer axle, steering, ball joints, and everything else. The worst thing you're going to have to do is tap the dust shield back flat with the chisel vs having to replace something expensive (seems like only the hard to get and expensive parts break :fs1: ).

[mvusse]

30mm sounded a bit small for that, knew it was one of those two. The driveshaft yoke nuts are 30mm then.

 

D30 yoke nut is 1 1/8", don't know about rear axle (35/44/8.25/8.8 ).

 

Transfer case fill and drain plugs are 30mm.

[Garvin]

30mm sounded a bit small for that, knew it was one of those two. The driveshaft yoke nuts are 30mm then.

 

D30 yoke nut is 1 1/8", don't know about rear axle (35/44/8.25/8.8 ).

 

Transfer case fill and drain plugs are 30mm.

 

On a Dana 35/30lp on the TJ I'm working on, the yokes are both 30mm, same on the transfer case. Besides being lp vs hp, the yokes should all be the same. Guess it all matters where it was built or something.

[Bounty Hunter]

Another easy method for removing the bearing assemblies is to back out the 3 hub bolts 1/8" at a time, then cover the bolt head with a socket and tap the bolt. This pushes the bearing assembly out of the knuckle 1/8" at a time. Beats the BFH and chisel method.

[terrawombat]

I had a pair of front wheel bearings that were so firmly implanted into the hubs that I used a stubby piece of 3/4" steel rod and wedged it between the rounded part of the axle yoke and the axle hub. I then used the torque of the steering wheel (which is more than you think) to get the wheel bearing moving. Once I broke it free, I was able to tap it out with a hammer.

 

Kind of hard to explain, should have taken a picture...it makes perfect sense when you see it.

[Jaime]

Well I changed the wheel bearings but it was an adventure. I am writing this in hope if somebody else sees what I saw they won't make the same mistake I did.

 

Remember that this is my first 4 wheel drive vehicle. I ordered the parts from O'reillys. The sales person said you need two outer bearings two inner bearings plus races 4 seals plus an inner seal. When I looked at the FSM that is what it showed looking at the picture. The two inner bearings did not look right but I took the parts anyways. I took the hub off the spindle using the socked on the head of the three bolts and hitting it with a hammer, quite easy actually just time consuming. I then proceed to take the hub apart. The first thing I see is that the two inner bearings are wrong but I continue and manage to take it apart after some hammering cussing and plain old desperation. I then try to take the outer bearing off but it breaks apart leaving only the inner metal part that is seized on to the hub. Great now I need a machine shop. So I go back to O'reillys to exchange the wrong bearing. This time I get a more experienced person. He says the computer shows a complete hub assembly. What you're kidding I say. He keeps quiet but I know he wants to laugh because I would too. So he says that there is one in town at another store but will have to order the other one unless the truck coming into town is bringing another one. I tell him to go ahead and order the one and I'll pick up the one in town. After picking up the hub I go home to install it. I then go through FSM but I don't see where it says to just replace the complete hub. Now I see that the spindle nut has to be torqued to 175 ft lbs but my torque wrench only goes to 70f lb. So off I go to Harbor Freight and get one that goes to 300 ft lbs. On the way back I get a call from O'reillys, the part is in. I get the part and install them. To remove the other side and install the new one only took about 40 min but I spent all day doing everything else. I hope you can learn from my inexperience. But it's all good now.

 

I wanted to add some smilies but could not make them work.

Thanks

Jaime

[mvusse]

The separate bearings and races are for a 2wd axle. 4wd MJs (as well as xj, tj, yj, zj, jk, wj and probably others) all use a unit bearing, which is the "complete hub assembly".

 

In later years (89? 90? 91?) the 2wd axles were changed to the 4wd unit bearing with a dummy shaft in it (a stub shaft with a flat back side instead of ears for a u joint).

[Eagle]

The separate bearings and races are for a 2wd axle. 4wd MJs (as well as xj, tj, yj, zj, jk, wj and probably others) all use a unit bearing, which is the "complete hub assembly".

The early hub units for the 4WD vehicles WERE serviceable. Last I knew, Quadratec still sold the individual parts. But by the time you bought the inner and out bearings, the two seals required, and I think there was one other part needed ... you were within a couple of bucks of buying a complete hub/bearing unit. And rebuilding the hubs requires a 12-ton hydraulic shop press.

 

But, technically, the guy at O'Reilly's was correct.

 

The later hubs (1990 and newer) are not rebuildable.

[mvusse]

Yes, you will have to replace the unit bearing as a whole. They are not supposed to be serviceable or greasable. They cost anywhere from $90 to $130 depending on year and come with only a one year warranty.

 

Depending on what style it may or may be be possible to take it apart without ruing it so you could grease it, but as Eagle said, it takes a hydraulic press with some special attachments.

[Eagle]

Yes, you will have to replace the unit bearing as a whole. They are not supposed to be serviceable or greasable.

http://www.quadratec.com/advisor/jeep_o ... _brake.php

 

See parts # 16 thru 20. For 1984 to 1989 only.

 

[mvusse]

This is what my 87 used when it was stock:

[Eagle]

This is what my 87 used when it was stock:

Yes ... and those parts in my post immediately above yours are the parts to rebuild that hub.