Diff Nitro Gear and Axle One piece axle kit issue

[Kens1979cj5]

Anyone have any specs/install/experience info? I ordered the

Nitro Gear & Axle 29 Spline Nitro One Piece Narrow Track Rear Axle Kit for AMC Model 20 Jeep CJ5 | CJ7 1976-1983

AXCJS

I called Nitro today because there were no specs or install info. I’m a little blown away by the answer I received. “We don’t have any for that kit. We ship them to shops that know what they are doing.” (Chew inside of jaw off). I said “You don’t have specs for the spacer?” “Nope”.
That being said, I’ve seen many other kits that require the bearing spacer be modified to place the bearing .03 to .08 outside the axle tube. At this point I don’t know if this kit is designed differently or requires the same range. Look forward to participating in this forum, as the defective gene kicked back in and I purchased another CJ after not having one for about 30 years.

 

[TSB8C]

Didn't use their kit, but have used two others over the years. The spacing and objective is the same regardless. Basically you need to get the spacing such that when you bolt on the brake backing plate (and seal, etc) you are preloading the pressure on the outer race of the bearing. Think of it like this: The inner and outer races of the bearing must be "sandwiched" between two immovable surfaces so that neither can spin, forcing the motion to be applied only to the bearing runners themselves. The inner race of the bearing is "sandwiched" between the stop on the axle shaft itself and the lock ring (when you press both onto the shaft and tightly against the stop (the ridge milled on the shaft. So the inner race of the bearing spins WITH the axle, not ON or AROUND it. The outer race of the bearing is "sandwiched" between the spacer that you are inserting into the axle tube and the brake backing plate when you bolt it on. Too little of the bearing extending out and you have insufficient pressure on the outer race of the bearing to keep it from spinning in the tube. Too much bearing sticking out and it will cause the bearing to bind when you tighten the backing plate against it. So you must adjust the thickness of the spacer to achieve the proper amount of bearing protrusion to have a tight, but not binding, pressure against the outer race of the bearing when it's all bolted up. Main points to watch are when grinding the spacer to achieve the desired thickness, keep it straight. You must maintain a uniform thickness all the way around so that you have even pressure on the bearing all around. Get a little cockeyed when grinding and the thickness will vary in spots, causing the bearing to sit weird. And Second, GREASE! Pack the bearings real well before installing, and then shove another good glob of grease into the bearing area in the tube before bolting up the outer seal and backing plate. You basically want enough grease such that when it is hot and liquified, it is full up to the lower edge of the outer seal. More than that and it will attempt to leak out. Less than that and you risk bearing failure. Remember that diff oil is NOT lubricating these bearings like many cars/trucks do. That inner seal prevents that. The grease you put in now is all it gets.

Another option to grinding the spacer is the use of shims. Some don't recommend this route. I'll agree it is a bit more to deal with in terms of sealant and getting it all lined up, but is an easier option if you have no reliable way to evenly grind a few thousandths at a time from the spacer.

I have the Yukon Gear setup currently, which looks identical in terms of parts used and design as the Nitro Gear kit. So should be the same process as I stated.

 

[Kens1979cj5]

Didn't use their kit, but have used two others over the years. The spacing and objective is the same regardless. Basically you need to get the spacing such that when you bolt on the brake backing plate (and seal, etc) you are preloading the pressure on the outer race of the bearing. Think of it like this: The inner and outer races of the bearing must be "sandwiched" between two immovable surfaces so that neither can spin, forcing the motion to be applied only to the bearing runners themselves. The inner race of the bearing is "sandwiched" between the stop on the axle shaft itself and the lock ring (when you press both onto the shaft and tightly against the stop (the ridge milled on the shaft. So the inner race of the bearing spins WITH the axle, not ON or AROUND it. The outer race of the bearing is "sandwiched" between the spacer that you are inserting into the axle tube and the brake backing plate when you bolt it on. Too little of the bearing extending out and you have insufficient pressure on the outer race of the bearing to keep it from spinning in the tube. Too much bearing sticking out and it will cause the bearing to bind when you tighten the backing plate against it. So you must adjust the thickness of the spacer to achieve the proper amount of bearing protrusion to have a tight, but not binding, pressure against the outer race of the bearing when it's all bolted up. Main points to watch are when grinding the spacer to achieve the desired thickness, keep it straight. You must maintain a uniform thickness all the way around so that you have even pressure on the bearing all around. Get a little cockeyed when grinding and the thickness will vary in spots, causing the bearing to sit weird. And Second, GREASE! Pack the bearings real well before installing, and then shove another good glob of grease into the bearing area in the tube before bolting up the outer seal and backing plate. You basically want enough grease such that when it is hot and liquified, it is full up to the lower edge of the outer seal. More than that and it will attempt to leak out. Less than that and you risk bearing failure. Remember that diff oil is NOT lubricating these bearings like many cars/trucks do. That inner seal prevents that. The grease you put in now is all it gets.

Another option to grinding the spacer is the use of shims. Some don't recommend this route. I'll agree it is a bit more to deal with in terms of sealant and getting it all lined up, but is an easier option if you have no reliable way to evenly grind a few thousandths at a time from the spacer.

I have the Yukon Gear setup currently, which looks identical in terms of parts used and design as the Nitro Gear kit. So should be the same process as I stated.

Thanks! Great info ! I’m familiar with the process, just curious about the Nitro kit. You are thinking the same way I am. Blows my mind what the guy at Nitro told me.

 

[RiverandSand]

I attached the Yukon instructions. I have the G2 axle set in mine , but couldn't get instructions to upload, they are very similar install. The G2s use Set 9 bearings, not sure about the Nitros. Sound like they just repackaged someone else's kit.

 

[Kens1979cj5]

Got it done. Went with .06 bearing clearance.

 

[TSB8C]

Looks great.