rotors same part # BUT different size!

[LArry 200 TJ]

2000 TJ
Not sure if anyone else has run into this, my rotors were to far gone to have turned so I bought new ones. Did the normal brake job and when I put the rim back on the wheel would not budge. Even the jeep would not move just spun the tires (cool) but not what I wanted after changing rotors and pads. So I bled the lines again....changed to the spare tire thinking the rim was some how to blame.....and after that thought the caliper was bad changed it for a new one.....same problem.

Here I guess in 1999 the rotors "hub" (may be the wrong term) depth went from about 2 3/8 in to 2 in-that 3/8 was enough to push against the inside pad and lock things up once the lugs were tightned up.
After some cross checking/measuring of parts on the shelf the store (o'reily's) was very good about switching the rotors out and even having to upgrade to get the corect size with no cost to me. I had even painted the hub part on the rotor red.

So you thought it would only take about 45 minutes ha ha ha ha ha

[Stu Olson]

From the D30 brake overhaul write-up on my site.....

NOTE: Around 2001 or there about (I don't think anyone knows the exact date), Chrysler changed the dimensions of the rotor and the unit bearing. In doing so, auto parts stores sometimes don't realize that there are two different rotors (they list a single part number) or they have the part numbers listed for wrong year(s). It is also possible that your TJ got some of the last "old style" rotors but your friend, with the same year TJ as yours, has different ones (depending on when it was assembled).

So the point is that the thickness of the rotor hat, that part that slips over your wheel studs, is different between the two rotor styles. The difference is about 1/8" and can be easily detected with a ruler. Lay the rotor on a flat surface with the hat up. Put a ruler down through the large hole in the middle of the rotor and note the measurement. Take the ruler (or the rotor if you wish) with you to the auto parts store when you get your new rotors and make certain the new ones share that same measurement. If they are wrong, they will still mount on your vehicle just fine....but when you slip your tire onto the studs and tighten the lug nuts, it will bind and you will NOT be able to rotate your tire.

I am not 100% certain of the year (it doesn't matter much since one needs to verify the rotor to be sure anyway).....but one can change rotor dimensions on the TJ as long as you get matching unit bearings (with the appropriate change in dimension) to go along with it.

[LArry 200 TJ]

yes sir that is is exactly what I wanted to say lol. Brakes and rotors being a usually easy job to do I did not research the operation any. I have been to your site a few times looking at future projects for my TJ for suspension & general upgrades, and whatever else I havent thought of yet (havent been on for a few months). Being moderatly mechanically enclined I venture out with variuose tools and a tech book and become almost dangerous Mua ha ha.

Anyway a great write up from you -like I have read in your site on other subjects. hope this warns others still using stock axles.