Short post, but important. Most of the information out there is about how to properly pre-load the style of wheel bearings that don’t have the integrated dust seal. The new Matco brakes come with integrated seals on the bearings and need a special procedure for install. According to the guide, the bearings should have 18-26 inch-pounds of drag when properly installed. This is bearing drag, not how much you tighten the axle nut. Here’s how I got what I think is the correct amount of preload on the bearings.
The only special tool required for this was a fish scale and some string. Everything else I used was standard shop tools. I measured the radius of the tire to be 7″, so to get 18-26 in-lbs of drag at 7″ required 2.4 – 3.7 lbs of drag. By wrapping the string around the tire tread and using the fish scale to pull it, I was able to tighten the nut until I got a reading on the scale between those numbers.
I used a 12″ #30 drill bit to drill down from the top through the top part of the axle. I then removed the wheel and tire, reinstalled the nut and held it in place with a 1/8″ rivet. I then used a 90 degree drill adapter and a stubby #30 to drill up from the bottom. I like to color the flat that lines up with the hole once its properly torqued. If I ever have to change a tire in the field, I know exactly which flat to stop at to get it close and then I can double-check the torque once I get home.
After everything was done, I went back and checked the torque value of the nuts. The right side took 150 in-lbs to get into the lower end of the drag value. The left side was a little more in the middle of the drag range and took 175 in-lbs on the nut to get there.
~Paul
Total Build Time: 947.1 hours