How To Adjust Wheel Bearing Clearance?

Whether the axial clearance of automobile hub bearing (also known as pretightness) is adjusted properly or not will directly affect the sliding performance of automobile, increase fuel consumption, and even endanger driving safety.  If wheel hub bearing adjustment too tight (that is, the axial clearance is too small), increased rolling friction resistance, reduces the vehicles glide performance, fuel 

consumption increase (increased about 2.1 ~ 8%), driving bearing overheating, the grease outflows, destroyed the bearing lubrication condition, serious when bearing caused by high temperature sintering, make hub disassembly difficulty;  If the wheel hub bearing adjustment too loose (that is, the axial clearance is too large), the driving wheel deflection of produce and put the first failure, increase the tyres and related parts is not normal wear and tear, when the steering knuckle or half axle sleeve pipe thread and nut thread due to wear and tear that both fit clearance at the time, not may cause "flywheel" phenomenon, endanger safety.Therefore, in the warranty work, we should pay attention to the adjustment of hub bearing axial clearance.  

At present, there are mainly two ways to adjust the axial clearance of automobile hub bearings in the instructions and materials of various manufacturers:  

The first is to use the torque of 196~245 N.M(20~ 25kGF. m) (the value is CA141 car, each manufacturer has different provisions on the value), adjust the nut tightening, in the tightening process should be to the positive and negative direction of the wheel, in order to make the bearing roller correctly contact with the inner and outer four cone surface,  Then return the adjusting nut about 1/6 to 1/4 turn.  

The second is to use a spanner about 400mm or 500mm long to turn the adjusting nut until the hub can no longer be turned, and then back 1/4, 1/5, 1/6, 1/7, 1/8 turn.  The two methods introduced above can only be applied to newly produced or overhauled vehicles within 2~3 two guarantees, and the second method is basically used around the country at present.  

When vehicles use after a period of time, the adjusting nut and the steering knuckle or axle fitting clearance between pipe thread will gradually increase, this gap is greater than 0.50 mm, while the change the new nut, but due to the steering knuckle or half shaft sleeve pipe thread has wear (knuckle or half axle sleeve pipe thread is not damaged, generally does not change), and zhejiang screw type lie thread machining precision,  There is always a certain limit between them, if you adjust the axial clearance of the bearing according to the two methods introduced above, when the lock nut is tightened outside, it is bound to make the axial clearance of the bearing too small, or even no, so that the wheel hub rotation heavy, increase the driving of the car.  

Resistance, and the lubrication surface of the bearing roller and the outer seat ring is destroyed, shortening the service life of the bearing.  In addition, when the internal and external tapered bearing wear face wear or more severe, the rear axle shell casing pressure fashionable size error, adjusting nut and the contact surface grinding of bearing inner race out deeper annular groove, even if the adjusting nut and tighten, the axial push-pull wheel with both hands, will still feel gap and wheel for bearing axial clearance is too large. Therefore, the two methods introduced above still cannot make the axial clearance of the hub meet the requirements.