4 installing the air locker, Air locker final assembly, Final backlash checking – ARB RD158 User Manual
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4 Installing the Air Locker
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4.8
Air Locker Final Assembly
c Remove the seal housing, shim pack, and master shim, and clean
all parts of the differential assembly. It is very important to make 
sure the seal housing grooves are free from any contaminants (eg: 
water, dirt, metal fillings, etc.) 
c Lubricate the O-rings with oil (prior to assembly), then stretch them
over the bearing journal and release them into the grooves.
NOTE :
Do not roll the O-rings onto the seal housing as this 
will damage them. 
c Place the bearing cups onto their respective bearing cones. 
c Install the seal housing over the O-rings by gently applying a 
downward twisting motion. This will allow the O-rings to gently 
engage. 
c Assemble the shim pack and master shim. 
c Point the seal housing tube straight out of the housing, hold the 
shims and tapered roller bearing cups in place, and insert and hold 
the Air Locker into the differential housing. 
c Install the bearing cap on the ring gear side. 
c Check to see if the bearing cap on the seal housing side fits over 
the tube without fouling.
NOTE :
Do not forget to check the bearing caps are turned the 
correct way around. 
c Install all bearing cap bolts and torque to manufacturer’s specs.
 
 
4.9
Final Backlash Checking
c Relieve all tension on the housing spreader. 
c Tighten all bearing cap bolts with a torque wrench to the torque 
specified in your vehicle manufacturer’s service manual.
c Set a depth indicator on one of the ring gear teeth as in
Figure 15.
c While supporting the pinion gear by holding the drive shaft, rotate
the differential in both directions while observing the maximum 
variation in depth from the indicator (i.e., the highest value minus 
the lowest value). This value is referred to as the ring and pinion 
backlash. 
