new unit bearings???

[Huck]

After replying to thread about Alloy axles, I remembered a question that I wanted to ask the masses.

For those Jeepers running unit bearings on their front axles, how many folks have replaced them? If so,
1) after how many miles?
2) after what type of useage: hard-core rock crawling, hard-core mall crawling, big tires or stockers, etc????

The reason I ask is that this little bit of required maintenance appears to go over-looked by many Jeepers. Most folks, it seemed in my informal trail conversations, feel that if unit bearing feels tight it is still 'muy bueno'. I didn't realize just how much of a difference changing mine out would make. I made a decision to step up to 30 spline outers and new unit bearings about a month or so ago. I did this to prepare for another future upgrade and because I felt my unit bearings were due for replacement. The drive home after the install was inspiring. I regularly drive my lifted heep at freeway speeds and it handles very well. Well, the drive home was even smoother with no play in the steering wheel. The tracking was excellent and nothing regarding the tires or alignment was touched. I couldn't believe the difference.
I pulled my old unit bearings out of their boxes and couldn't get them to show any play what-so-ever. I spoke with the mechanic who did the install for me and explained my thoughts. He let me know that I wasn't imagining things and the new unit bearings will tighten up the handling.

My rig has been running 31's, 33's, and 35's for the past 73,0000 miles and been used for some of our more difficult trail running. The new bearings were needed in my heep after that type of useage and mileage. Knowing what I know now, I prolly would have replaced them sooner.....
Just some thoughts about a part that doesn't seem to get a lot of discussion...

[Jdemonto@Airpark Jeep Sales]

I am upgrading to A D44 axle with alloy usa shafts and thought while I'm there I might as well replace them...not sure what the life span is?? I have been running 37's for 50K miles and my jeep have 53k..what do you think??? Replace them?

Jason

[Huck]

Jason,
My first question would be what useage has the 'new' D44 axle been through. If you were asking about your current front axle with the 37's for 50K, then :fashizzle:. I would recommend replacing them and I think you'ld be surprised at the difference. If you are using a new axle for your upgrade, then why bother, unless you want to run 30 spline outers to take the punishment 37's can dish out. If you want to run 30 spline outers, you will need to buy the matching unit bearings, too.
HTH

[SHNIPE]

mine on my d30 had 126K plus and they were in need of replacing but they werent crcked or falling apart. just wobbly now i have gotten rid of them completely :D

[AZXJ]

We replace them regularly in the 40K milage range.. larger tires sizes seem to promote failure quicker. Also we have noticed that some of our Snowbird customers tend to go through them quicker due to diffrent climates..

Dave

[Antman]

I replaced mine about a year after buying my tj when it had about 90,000 miles on it and again at about 190,000. I now have 202,000 on it, but plan a hp D44 in the next six months. Both times, my UB's were still in good shape but I could notice a difference when first driving the rig. If you run big tires and wheel hard, you should be checking them regular. :sifone:

[azcharlie]

I replaced mine at 75,000 miles. I'm now running 37's so I thought it would be a good idea to replace them when I did. Plus at times on the trail they would make a weird noise. I also carry a spare unit bearing just in case I bust one of them on the trail.

[mingoglia]

I just turned 100k miles on mine but I bought the Jeep with 84k miles on it and it had stock size tires. My front left has been on it's way out for awhile... at least it squeaks like you wouldn't believe. I have a spare new one that (like Charlie) I keep in my rig as a spare. I've had the side in question apart twice since I've had this spare unit bearing and each time when I've put it back together I've forgot to pop the new one in. I figured it wasn't meant to be so just carry it with me until either it goes out completely or I remember to actually swap it out. ;) The same thing goes for the 12pt bolts that hold everything together. I tore them up pretty good when I lost a ujoint (result of the ujoint flopping around) and bought all new bolts for both sides. I keep them in my glove box and the 2 times I've had stuff apart I've forgot to swap in the bolts. :(

[RokNRich]

So what's the scoop on picking up a set ? If I remember, they are kind of pricy and are/were a dealer item. Is there an aftermarket alternative ?

I just did the wiggle test the other day and they seemed fine, 23K miles, on 35's most miles offroad.

[YGOHOME]

I bought two new ones from 4wheelers supply for super cheap about a year or so ago. they were the regular 27 spline ones. I gave my spare away though so I'm picking up another one from them today

[1BLKJP]

D*mn Ben, you should've let me know. I'd have given you one of the spares I have when you gave me those two.

I've changed mine out a couple times now. I can tell just driving mine when they are starting to go bad. You're right Huck it is something that's overlooked by many. I was one of them until the first time I changed them out and could tell the serious difference between worn out and new. :D

[Huck]

Rich- I'm not sure that the wiggle test does much. When the axle is in the unit bearing, the bearing is sandwiched and held together that way. That's the reason you don't want to drive on a unit bearing without the stub shaft holding it together. I don't know what play you would find in it while mounted on the heep.... I know when I was playing around with my old unit bearings I couldn't feel any play in them at all. The big difference being that I was using my hand as a lever and not a big tire on a rock. From my test, I would have thought that they were still just fine. Heck, I've got two with 27 spline Alloy outers sitting in the garage, as spares, now. I can't comment on how much factory spares run, but the 30 spline ones run ~$399 for a pair with the 30 spline Alloy USA outers.

My intent for starting this thread was twofold: Try to get people thinking about a part that many of us take for granted and to let folks know that changing them out (even ones we think are just fine) will produce some real nice benefits. I couldn't believe the amount of play in the steering wheel that is gone now. I am very impressed with how tight the front end feels again and its like driving around in a new Rubi again..... Seeing Todd post up about changing them out around 40,000 for his clients, reinforced my thinking that a lot of folks may be driving around with worn out unit bearings. My rig felt so much better, that I will be replacing them in regular intervals from now on.

This was not meant as a sales pitch, but to just fuel some thinking and to remove some wobble:aagh:

[Jdemonto@Airpark Jeep Sales]

Huck, My D44 is a housing only with 15K from a bone stock ruby. I am using my knuckles for the swap with new alloy usa shafts 30/27 spline and new 4.88R&P and new Eaton E-Locker...Of coarse a new install kit! Cole mentioned to me about going to a 30/30 setup with new unit bearings and had not thought much until you brought this thread up! I figureI would stay with the 30/27 setup...wouldn't you bust a U-joint before ever wrecking a outer stub?

Jason

[lancetkenyon]

I run the 30 spline unit bearings now, too. Been in for about 1K miles. I carry my old 27 splines with a set of stock Rubi axles. But I hope I never need them. I destroyed one of my old stocks when I snapped an outer Yukon stub shaft.

[mingoglia]

So what's the scoop on picking up a set ? If I remember, they are kind of pricy and are/were a dealer item. Is there an aftermarket alternative ?

I just did the wiggle test the other day and they seemed fine, 23K miles, on 35's most miles offroad.

If you're looking for stock ones contact Cole. He has them for silly cheap. They were like 1/4th of what I thought they would be. I almost think I paid like $50 or so.

[lancetkenyon]

$53.

[YGOHOME]

D*mn Ben, you should've let me know. :D

oh, no worries Jack, keep those as spares or use em if you need em.... anyways, when we wheel together they are all basically community parts to whoever needs em :D I just wanted a NEW one today cuz mine is making a little noise when I turn the drivers tire by hand with it up on jack stands... a light grind noise. might just be mud in between the rotor and dust shield too though. Now we'll have one more to have handy as a spare.

[Oldgamefreak]

How do you check these and how hard are they to change??

[vwkaferman]

Who carries these, anyone local? I thought about doing these this weekend along with new ball joints in hopes of curing some wobble woes.

Also, where did ya'll get the tool to take off the backside of the unit bearing (not sure what they're called, the funky bolts kinda like a star pattern)?

James

[Huck]

James,
I got mine through Joe at Absolute Off Road. I'm sure you can get them from most any reputable vendor and a couple may have them on the shelves. I believe the 'star' bolts you are referring to are the 3, 12-sided, 13mm bolts. Most folks find that using a 12-sided, 1/2-inch socket or wrench can also work, but the heads are 12-sided 13 mm.
HTH

[Markos]

I think I read that you want to try to find timken unit bearings if possible, but they are now very hard to come by. If anyone has additional info on that, feel free to chime in. I think the timken ones were around $100, and most other are made in China. I haven't changed mine yet, so most of this is just hearsay.

[vwkaferman]

Thanks for the info fellas. I'm pushing 197,000 miles on my baby, I reckon I could show it some love this weekend.

James

[Lonnie]

Began checking on prices after this thread started and found the Timken bearings at a local parts house for around $126 here in Tucson. The bearings are on my list of things to do this year, pushing around 70K miles and on 35's for the last five year. So I would guess they are past due. Just did the rear bearings and seals on the rear Dana 44 right before Christmas. They were starting to weep a little from the abuse. The jeep is starting to show its age and the hard miles its been on for the last nine years. But it still amazes me how well its held up thru all the abuse.

[vwkaferman]

Feller at Checker Auto in Gilbert said he could special order them, get them in same day by 2:30 pm, $114 and I *Think* he said he could get 10% off that. I'm heading out and gonna do it.

Do you have to pull the front axle shafts out to change these? I'm a noob when it comes to 4WD.

James