Brake rotor with studs on it?

[mytechtime]

I was looking at new rotors for my 84 Town Car, but I noticed that the studs are on the rotor instead of behind it. How does this change replacing the rotor?

[johnunit]

You want to replace (and repack with new grease) the wheel bearing. The rotor is effectively the outer half of the bearing unit, with the spindle being the inner race, and two (inner and outer) wheel bearing cages in between. Buy the bearings if you're gonna be in there anyway, they're like 20 bucks a side. The change compared to a modern sealed-bearing unit is that you undo the nut in the center of the rotor/bearing to remove the rotor, and when you pull off the rotor you'll be basically disassembling the bearing unit. So you'll be left with two bearing cages/rollers sitting on the spindle and a ton of grease. Take the bearings off, clean off all the grease from the spindle, and put new grease and bearings in place before you put the rotor on.

Then you will need to torque the nut at the end of the spindle in a special way once the rotor is back on. There are a ton of ways to do this, but I've had no comebacks at work by tightening the nut while spinning the rotor until I can feel some bind as I spin (usually roughly half a turn past where it starts to feel a bit tight), and then backing off to the edge of there being play when I shake the wheel up and down. A tiny bit of play is ok, but it should be "I can't be sure it's there" levels. too tight will burn up the bearings and cause further issues.

There'll also be a greasecap you have to remove to get to the nut. Replace it if you see any evidence of grease getting past it (onto the rotor or wheel). Also put in a new cotterpin on the spindle nut once you're done adjusting that.



Here is a shot of the spindle, without any brakes, the bearing rollers, and the dust shield (which your car may or may not still have). The thread for the spindle nut is right at the tip, then there's where the outer (smaller) bearing roller sits, and then right up close to the rest of the suspension is where the wider inner bearing sits.

[gadget73]

This setup is known as an integral hub rotor. It just means that the bearings ride in races in the rotor, rather than having a separate hub bearing assembly like newer cars have. This is old school stuff that requires hand packing grease into the bearing and setting it in there with the right amount of torque so it doesn't chew bearings or flop around. Its not hard to deal with, but its definitely different if you are used to newer vehicles.