1989 comanche mj Posted December 24, 2019 Share Posted December 24, 2019 I have a dana 30 from a 99 xj, was going to use in my MJ, however the rotors are different. Non abs. Are the spindles rotors and calipers different than the earlier xj front axles? Are the axle shafts the same, interchangeable with my 92 mj? Link to comment Share on other sites More sharing options...
jeeptec1 Posted December 24, 2019 Share Posted December 24, 2019 The brakes and hubs I believe are different. The axle shafts are different if one has abs and one doesn’t. If the 92 is non abs it will have the small joints in the axle. If it the 92 has abs it will have the larger joints. The later axle will have the large unjoints. I’m don’t remember if the 99 XJ had the low pinion front diff of not. I know 2000 and 01 definitely had low pinion front diff. If it is a high pinion swap it in. Just remember to get parts for that axle by what it came out of. Oh if it is high pinion the ring and pinion swap over. If it is low pinion they are totally different. Sent from my iPad using Tapatalk Link to comment Share on other sites More sharing options...
Eagle Posted December 24, 2019 Share Posted December 24, 2019 The following is from the draft of a book I started to write many years ago. It is copyrighted and by posting it here I do NOT grant anyone permission to distribute copies of it to anyone else, in any form. In general, the parts to be concerned with in keeping the front brakes compatible are the steering knuckles, the hub/bearing assemblies, the rotors, and the calipers. (There is a more complete enumeration of the interrelationship of these parts in Chapter 6, Axles.) Only two steering knuckle designs were used: 1984 through 1989, and 1990 through 2001. Left and right side knuckles are different part numbers within each group. Three different hub/bearing units were used. The hub/bearing units are the same for both sides of the vehicle. The different years for hub/bearing assemblies were: 1984 through 1989; 1990 through mid-1999 (composite rotors); and late-1999 through 2001 (cast rotors). Three rotor types were used: 1984 through 1989; 1990 through mid-1999 (composite); and late-1999 through 2001 (cast). Only two caliper types were used: 1984 through 1989, and 1990 through 2001. Left and right side calipers are different part numbers within each group. Link to comment Share on other sites More sharing options...
1989 comanche mj Posted December 25, 2019 Author Share Posted December 25, 2019 Great info, thanks! so 90 and up same calipers, just the mid 99 rotor and hub change. So the rotor has to match the hub or vice versa. I believe 2wd and 4wd rotors and calipers of the same type are interchangeable also, since I have scrapped 2wd xjs and after noticing newer rotors I swap the rotors calipers and pads over to keepers. Link to comment Share on other sites More sharing options...
AZJeff Posted December 25, 2019 Share Posted December 25, 2019 On 12/23/2019 at 10:59 PM, Eagle said: The following is from the draft of a book I started to write many years ago. It is copyrighted and by posting it here I do NOT grant anyone permission to distribute copies of it to anyone else, in any form. In general, the parts to be concerned with in keeping the front brakes compatible are the steering knuckles, the hub/bearing assemblies, the rotors, and the calipers. (There is a more complete enumeration of the interrelationship of these parts in Chapter 6, Axles.) Only two steering knuckle designs were used: 1984 through 1989, and 1990 through 2001. Left and right side knuckles are different part numbers within each group. Three different hub/bearing units were used. The hub/bearing units are the same for both sides of the vehicle. The different years for hub/bearing assemblies were: 1984 through 1989; 1990 through mid-1999 (composite rotors); and late-1999 through 2001 (cast rotors). Three rotor types were used: 1984 through 1989; 1990 through mid-1999 (composite); and late-1999 through 2001 (cast). Only two caliper types were used: 1984 through 1989, and 1990 through 2001. Left and right side calipers are different part numbers within each group. That's a nice write-up, Eagle. If the rest of your document is that concise, I want to encourage you to put it out there for others to leverage as a knowledge base for MJ/XJ owners. Stuff like this is starting to become a treasure for a vehicles that is at LEAST 19 years old, and possiby much older, nowadays. Link to comment Share on other sites More sharing options...
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