Quick D30 Question
05-23-2009, 05:05 PM
#1
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Quick D30 Question
Hey guys,
Went wheelin on Friday and toasted my already questionable front axle u joints. I am therefore looking to upgrade my shafts to the 297 shafts from the newer XJ's.
My question is, I want to get axle with unit bearings as well as my driverside one looks like it has seeped a bunch of grease out of it and I figure that bearings from a newer XJ would be in better shape than what I have now (hopefully). I seem to remember reading somewhere (of course I can't find it now) that the unit bearings changed slightly throughout production. What years are compatible with what? Is it just a matter of getting the rotors with it as well or is there more to it? Would I be better off trying to get ones from an earlier model with abs?
I'm going to keep searching but any help would be much appreciated.
Went wheelin on Friday and toasted my already questionable front axle u joints. I am therefore looking to upgrade my shafts to the 297 shafts from the newer XJ's.
My question is, I want to get axle with unit bearings as well as my driverside one looks like it has seeped a bunch of grease out of it and I figure that bearings from a newer XJ would be in better shape than what I have now (hopefully). I seem to remember reading somewhere (of course I can't find it now) that the unit bearings changed slightly throughout production. What years are compatible with what? Is it just a matter of getting the rotors with it as well or is there more to it? Would I be better off trying to get ones from an earlier model with abs?
I'm going to keep searching but any help would be much appreciated.
05-23-2009, 05:07 PM
#2
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You can use any Shafts and unit bearings out of either a new XJ or a 97+ TJ..
As for the unit bearings I've never heard that there was a change in them..
As for the unit bearings I've never heard that there was a change in them..
05-23-2009, 05:22 PM
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Found this on Naxja, figured I'd post it here in case anybody needs this information. Courtesy of Tim_MN on Naxja:
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.
1999.5 to 2001 unit bearing/hub on the left, 1990 to 1999.5 unit bearing/hub on the right
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.
1999.5 to 2001 unit bearing/hub on the left, 1990 to 1999.5 unit bearing/hub on the right
05-23-2009, 07:43 PM
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the ujoints from the new body style are larger not a lot but enough to make a difference when wheeling they will last longer then the old ones would
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05-23-2009, 08:19 PM
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Found this on Naxja, figured I'd post it here in case anybody needs this information. Courtesy of Tim_MN on Naxja:
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.
1999.5 to 2001 unit bearing/hub on the left, 1990 to 1999.5 unit bearing/hub on the right
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.
1999.5 to 2001 unit bearing/hub on the left, 1990 to 1999.5 unit bearing/hub on the right
06-07-2010, 10:45 PM
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New jeep owner question
So I'm hoping this is the place to ask this as it seems like you know a lot about brakes on the XJ. I just recently was gifted a 92 XJ (first jeep...really glad for sites like this and the people on them...been a big help learning). Thing is I think my knuckles need to be replaced. The integrated brake bracket has notches that somewhat line up with the pads, but are so worn that the pads will not seat properly (they drop straight through when the caliper is put on). From past experience I can't see any logical reason for the bracket to have notches past excessive wear. The caliper has to be replaced as it is leaking anyway. As I can't find a replacement knuckle with the notches my current ones have I'm guessing it's obvious that they need to be replaced, but as I'm new to jeeps I figured it would be better to ask. For the record the Jeep is NOT being driven. Feel free to laugh at the Rookie if this seems like a no brainer. Just getting started with this project (already feeling the jeep obsession). Thanks
06-08-2010, 11:02 AM
#10
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The last set of brake pads I got came with a bunch of little clip on shims. the pads over time create those grooves your talking bout and the shims are there to compensate for that.
10-06-2010, 12:00 AM
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Thanks 4x4utahcherokee for the info, sorry it's taken a while for the gratitude man 
I scored a pair of bead blasted knuckles off ebay, on the cheap and your dead on (the groves in my old knuckles brake brackets are down right scary). Given how bad the old knuckles were I'm glad to get them replaced. Also picked up new bearing hubs, bolts,calipers, u-joints, and brakes. Any tips on getting the old bearing hubs off to remove the knuckles? The old ones are so rusted up that it took little to no effort to round one of the 12 point bolts (even after a 2 day soak in PB blaster, followed by freeze off). I'm thinking as I'm not reusing my knuckles I could use a wide cut off wheel on my grinder and slip between the knuckle and the hub, and cut at the 3 points were the bolts meet the hub body (cut the hub not the knuckle). I've used this trick on my Honda accords before to free up a stuborn hub...just wondering what your (or anyone's...) thoughts are? Thanks again.
I scored a pair of bead blasted knuckles off ebay, on the cheap and your dead on (the groves in my old knuckles brake brackets are down right scary). Given how bad the old knuckles were I'm glad to get them replaced. Also picked up new bearing hubs, bolts,calipers, u-joints, and brakes. Any tips on getting the old bearing hubs off to remove the knuckles? The old ones are so rusted up that it took little to no effort to round one of the 12 point bolts (even after a 2 day soak in PB blaster, followed by freeze off). I'm thinking as I'm not reusing my knuckles I could use a wide cut off wheel on my grinder and slip between the knuckle and the hub, and cut at the 3 points were the bolts meet the hub body (cut the hub not the knuckle). I've used this trick on my Honda accords before to free up a stuborn hub...just wondering what your (or anyone's...) thoughts are? Thanks again.
04-08-2021, 09:15 PM
#14
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I would swap to 84-89 knuckles with bolt on caliper brackets. Luckily I swapped tgese on to my 92 axle on accident.
You could also stay with your worn out knuckles. And weld the grooves them grind or file them back to a true shape.
Mine are slightly grooved ive been dragging my feet on reshaping them
To the other guy
you could use a carbide burr on a die grinder and take the bolt head off. And don't do that again. Ive pulled apart a ton of dana30s without rounding a bolt head.
I pulled apart 1 grand cherokee and 4xj dana30s at the junk yard. All but like one had only one newer unit bearing.
I think the bigger ujoint is a spicer 5-760x
You could also stay with your worn out knuckles. And weld the grooves them grind or file them back to a true shape.
Mine are slightly grooved ive been dragging my feet on reshaping them
To the other guy
you could use a carbide burr on a die grinder and take the bolt head off. And don't do that again. Ive pulled apart a ton of dana30s without rounding a bolt head.
I pulled apart 1 grand cherokee and 4xj dana30s at the junk yard. All but like one had only one newer unit bearing.
I think the bigger ujoint is a spicer 5-760x
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