1999 Unit bearing / Hub offset questions

[Big_Mark]

I'm trying to get my brakes done before the weather turns to crap, rears are handled but the front is leaving my scratching my head.

#1 The Axles in my Jeep were transplants from a 1999 Cherokee that's all I know about them

Front Dana 30 no vacuum business

Rear Chrysler 8.25

 

I got the calipers off and rotors off, both sides are in need of new parts, since I have it apart I decided to look into replacing the Unit bearings. Looking on Oreilys  I discovered there are 2 varieties, one with a 1.91" flange offset and one with a 2.133" offset easy enough since it's all apart I went and measured and discovered the Drivers side has a 1.91" offset

 

 

while the passenger side has a 2.133" offset.

 

 

 

WTF 

 

I am considering replacing both with 1.91 offset flanges since I have 1" spacers to help with wheel offset, my question is are the axle stub shafts for the 1.91" offset flange the same as the ones that go into the 2.133" offset flanged Unit bearings?

 

Are the caliper brackets for the 1.91 the same as the 2.133 set up?

 

I'd pull the bearings but the only giant sized socket that I don't (yet) own is a 36mm" 

 

any info is appreciated, thanks!

[OldSch88L]

From what I could find, there's two varieties of brake rotors: cast iron (3" tall) and composite (3.25") but only one model of caliper, so my guess is that those different offset wheel bearings are to accomodate their respective brake rotors.

[Big_Mark]

Thanks OldSck88L that makes sense, I'll check the depth of the rotors, BTW on the Drivers side (short hub) the inner pad was gone all together so I suspect you are on to something here.

[Big_Mark]

O.k. I went and checked, sure enough the overall depth of the unit bearings are the same (as is the depth of the stub shaft), the only difference between the unit bearing is the flange offset. My rotors are 2 7/8" deep (both)

 

 

so it seems I need the 2.133" unit bearings, and to be sure the rotors are the right depth!

 

Thanks again!

[ghetdjc320]

99 was a changeover year. Mid year they updated the hubs and added longer wheel studs. Also went to the composite rotors at the same time so the longer studs made up the difference. They are all interchangeable but would recommend the rotors/wheel bearings be matched. 

[Big_Mark]

I went with the larger offset Unit Bearing and it was a tight fit on the insides of the calipers with fresh pads. I think the other unit bearing would have made it easier to install the calipers however it all fit together as expected and the brakes do work. Over time the pads will wear and the calipers will move closer to the inside of the axles so I'll run it like this.

Driving around without the friction of bad U-joints has made a huge improvement in performance. Also being able to stop the truck without grinding noises is a bonus 

 

Thanks for the insight folks