Results 1 to 2 of 2

Thread: Unit Bearing Interchangability

  1. #1
    Join Date
    May 2009
    Location
    Near Vancouver, BC, Canada
    Posts
    61

    Default Unit Bearing Interchangability

    I noticed a couple days ago that my front axle u-joints are pooched so I've been looking into what options I have as far as upgrades. It is fairly commonly known that the newer XJ's came with bigger u-joints so I am going to get those but for ease of installation I wanted to get the unit bearings with the axles and install them as a unit (that and mine are puking grease all over the insides and I'm hoping the newer ones will be in better shape). Here's what I found:

    Mid 1999 was the change over. 1990 to 2001 parts will interchange provided your hubs and rotors match, read on.

    Three different hub/bearing units were used over the years on XJ's. The hub/bearing units are the same part number for both sides of the vehicle. The model years for hub/bearing assemblies were:

    1) 1984 through 1989 (early style rotors)

    2) 1990 through mid-1999 (composite rotors)

    3) late-1999 through 2001 (cast rotors).

    ** You need to match brake rotors to the unit bearing/hubs on your XJ D30 axle. **

    Lay the rotor on your bench and measure from the bench to the top of the rotor.

    Composite rotors will have an overall height of 3 3/16". Composite rotors will have a thin sheet metal like appearance at the lug nut holes where the studs come through and measure about 1/8 "(.125) thick in this area. Composite rotors have a rounded off corner at the wheel mounting surface and look like two pieces joined together.

    Cast rotors will have an overall height of 3 1/16". Cast rotors are thicker at the lug nut holes and measure between 1/4" (.250) to 5/16 (.320) in this area. Cast rotors have a square corner at the wheel mounting surface and look like they are one solid piece of metal.

    Parts store replacement rotors may have a different appearance but should measure about the same.



    On late 1999 - 2001 unit bearing/hubs the ring around the 36MM shaft retaining nut is almost 3/4 inch tall and the hub has longer lug nut studs than older hubs ( see picture). These hubs use cast rotors.

    On early 1990 - 1999 unit bearing/hubs the ring around 36MM shaft retaining nut is about 1/2 inch tall (see picture). These hubs use composite rotors.

    Two steering knuckle designs were used: 1984 to 1989 and 1990 to 2001. Left and right side knuckles have different part numbers.

    Two types of brake caliper styles were used: 1984 to 1989 and 1990 to 2001. Left and right sides are different part numbers.
    White 1991 XJ Sport - 4.0L, 5spd, 2-3" Spacer/AAL lift w/ RE shocks, 31/10.50r15 Cooper Discoverer STT's on 15x8 wagon wheels with 4" backspacing.
    Alot More to come.

  2. #2
    muddeprived's Avatar
    muddeprived is offline Level: Uber Jeep Cherokee Trailer Queen
    Join Date
    Mar 2009
    Location
    beaver Falls, PA
    Posts
    1,294

    Default

    Nice info. I picked up some 2004 wrangler hub assemblies from daveysjeeps.com for i think 50. They were like new and bolted right up.

Similar Threads

  1. 99 XJ fuel gauge sending unit
    By texcuda in forum OEM/Factory
    Replies: 3
    Last Post: 02-04-2011, 05:01 AM
  2. 38 tooth speedo gear & sending unit $75
    By W.O.R.P.Offroad in forum For Sale
    Replies: 0
    Last Post: 08-14-2010, 05:28 PM
  3. Bearing Basics
    By 96xj in forum Technical "HOW TO" Articles
    Replies: 3
    Last Post: 04-01-2010, 06:28 AM
  4. OME reading on gas sending unit?
    By bassackwards in forum Modified
    Replies: 0
    Last Post: 02-27-2010, 01:39 PM
  5. What are the steps to retrofit an a/c unit?
    By greenchevy in forum OEM/Factory
    Replies: 3
    Last Post: 06-13-2009, 07:11 AM

Tags for this Thread

Bookmarks

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •