Front stub axle seal replacements require special precautions. The seals are pressed into a side bearing retainer, which must be removed to replace a leaking seal. The side bearing retainers also control front differential side bearing preload, as well as ring and pinion backlash. When replacing a stub axle seal, mark the position of the side bearing retainer before unthreading the retainer. Remove only one side bearing retainer at a time, or you’ll risk disturbing the differential adjustments. If you’ve marked the position before removal, the correctly installed position of the side bearing retainer will be obvious, as you will be unable to turn the retainer another complete turn.
The driveaxles on some Subaru vehicles are pressed into the wheel hub with a light press fit. Blasting the axle out of the hub with an air chisel, center punch or other implement of destruction invites damage to the wheel bearings. All of the force brought to bear by these methods finds its way to the wheel bearings, possibly damaging their races or balls. Special tools are available for removing and installing (shown) press-fit driveaxles. Ignoring these cautions invites a comeback for noisy wheel bearings shortly after your CV axle repair work.
Some Subaru inner CV joint boots include a series of rubber O-rings that ride in the bottom of the CV boot creases. These O-rings keep the CV boot from rubbing against itself during sharp turning maneuvers and extend the life of the boot. If the original CV boot is torn or otherwise damaged, make sure its replacement includes this feature.
When replacing the rear wheel bearings on AWD Subaru Legacy, Impreza, SVX and Forester vehicles, do not overtorque the lateral link bolt (arrow) that secures the two trans-verse suspension arms to the wheel bearing housing. Do not use an impact wrench to remove or install the bolt. The proper torque is probably lower than you might think. The torque values are different for different models and years, so refer to the appropriate service manual for the proper specs for the vehicle you are working on. If this bolt is overtorqued, it can deform the housing and may lead to a repeat failure of the wheel bearing.
If you encounter a repeat wheel bearing failure in an unreasonably short period of time, the housing may have been deformed during the first repair. Replacement of the bearing and housing may be required.
There are some other points to keep in mind when working on the front and rear wheel bearings. Never loosen or tighten the axle nut with the weight of the vehicle on the wheel. The vehicle should be in the air with the wheel removed prior to loosening or tightening the axle nut. If this precaution is not taken, damage to the wheel bearing may occur. The axle nuts are not reusable. A new nut should be used with the new bearing. Always insure that the new bearing is properly packed with suitable wheel bearing grease. The grease the bearing is shipped with is not sufficient. Always use the proper special tools to install the bearing and torque the axle nut to the correct specifications. To avoid wheel bearing damage, never use air tools to tighten or loosen a wheel bearing nut.