I need to replace all the bearing in the middle axle on a friend’s 2007 Polaris Sportsmen 500 6x6. The middle axle housing bearings blew up and both swing arm housing bearings were bad as well. The parts are on order and while I wait for them to come in I’ve noticed confusing information on the torque spec on the axle nuts in the service manual. First, the disk side axle nut torque is 120 ft. lbs. on the middle axle – this makes sense as it’s tightened against a normal ball bearing so you can torque all you want. The axle nut on the sprocket side states that an 8-10 ft. lbs torque is required. At first this made plenty of sense to me because the middle axle housing has tapered bearing (cone/cup) and like a trailer wheel bearing, too much torque will lead to bearing failure. Where the confusion started is when I looked at the rear housing axle torque specs. Both middle and rear housing have the same cone/cup tapered bearings yet the torque on the rear axle is 150 ft. lbs.! Why such a drastic variance in torque between both axles? Why 8-10 ft. lbs on the middle axle and 150 ft. lbs on the rear axle? Has anyone encountered this? This Polaris was serviced a year for chain and sprocket and now the bearings have blown up. Could the last mechanic have torqued the middle axle nut to over 100 ft lbs when only 8-10 ft lbs is required?
I hope someone can shed some on light on this.
I hope someone can shed some on light on this.