TJ: D 30 problems

[Mtbikbob]

Here I go again. Why does it feel like I am the only with mechanical fit up problems? Does every mechanic go through this?

Installed an older assembly axle set. The housing, carrier, everything as a unit.
A D-30 front end. Got the whole assembly bolted up working good, then came time to put on the rotors and throw on the tires. Jeep won't roll. Back up on the jack, took off tires, examined rotors. The rotors are against the backets. In other words they are needing to be offset from the axle. Compared the assembly I took out to the one being placed and sure enough, there is about a 1/4 inch difference from the outside flange of the axle to the rotor bracket assembly.
I am at a loss, what is wrong and how do I fix it?

I pulled the axles themselves out and placed 2 washers between the housing where it bolts up with the 3 bolts, but I am sure that is not the answer nor is it good for the assembly, but it works, to get the jeep rolling. Any ideas?

[NAILER341]

You have the wrong unit bearings on there.
I'm assuming the axle shaft assemblies including unit bearings are from a different dana 30?

[Mtbikbob]

Hmmm...forgive me. What are unit bearings? Before or after the hub? I did not take this particular hub assembly apart. It came to me this way. So, yes it may be assembled wrong... or rather it must be wrong somewhere. According to my Haynes book this unit is a one piece as well, only the older models can be taken apart. Yes? What I am not sure of is what exactly can I remove.

[Mtbikbob]

[IMG][/IMG]

This is a unit hub?

[NAILER341]

This is a unit bearing:



They are not the same on all jeeps. The offset of the unit bearing is likely causing your issue.

[Materdaddy]

Very true. Your new D30 was probably from a WJ or something other than a TJ/LJ. I have both WJ and TJ unit bearings in my garage I can bring over and show you.

In fact, I can give you my spare TJ unit bearings now if you want to find me TJ ones at a later date. (i.e., if you need to get your Jeep moving again).

You should be able to pull your unit bearings off your old D30 though.

Give me a call Bob! (My cell changed, so PM me for the new number.)

[aw12345]

There are different unit bearings and rotors. in 97 the TJ's used a different unit bearing and a composite brake rotor. this bearing does not work with later rotors. so you can either use different rotors or change the unit bearings .

[Mtbikbob]

Always a catch to some of these mechanical things. Ok, call me slow....again. So to solve my problem I took the inner axle assembly out of the Dana 30 3.07 gearing I took off and put them into the Dana 30 4.88 gearing I put in. Problem solved. But its good to know more for the next time I change things.

Thanks again for the information.

p.s. I did try to take off the unit bearing and did not succeed. How does one take them off. Again I am working out of my garage so limited on tools.

[OU812]

If you back those three bolts out about a quart inch and tap them with a dead blow hammer they usually pop right out. I always use a little aniseize on the the hub and the three bolt to make it easier next time. If that doesn't do it for you you can try this old trick...
http://www.stu-offroad.com/axle/unit...tbearing-1.htm

[Jeeperator]

I had the same issue when doing my d30 hp swap. I bought brand new later model (2000 and up) unit bearings and the 1997 rotors were the wrong offset Art had a extra set of rotors laying around and that fixed the problem. Thanks again art.

[bails85]

i had this problem. parts house gave me the wrong rotor from a different year. the thickness of the rotor that bgoes over the lugs was too thin so when i tightened down the whell it was just locked on. just a thought.

[Jeeperator]

I believe 1997-1999 rotors and unit bearings are the same and 2000-2006 are the same. The 2 different groups will not interchange though.It is also my understanding the newer unit bearing are better or stronger in some way also.If I am wrong please correct me. When I did my d30 hp swap I figured I might as well upgrade the the newer unit bearings since I was changing them anyway. This is when I figured out the 1997 rotors wouldnt fit with the newr unit bearings. Tightened them down also and wheel was locke up.

[6spdYJ]

If I'm not mistaken, which I probably am... One era had straight roller bearings while another had tapered rollers. This is what I was told by an indistrial bearing supplier when I was looking into the unit bearings.