1st, are you talking about the front or rear rotors, that you cant get off?

The front rotors you need to use a dead blow mallet to remove the rotors, they are a tight fit and press onto the axle, when the rims are torqued down to spec. they assist in keeping the front rotors seated tightly, and yes, the slight rusting will "lock" the rotors down pretty well. Just use a 2lb dead blow mallet, and tap the front rotors outward to break them loose, then you can remove them.

The Rear rotors are a bit different, they press on very tightly, and if you look at the rotor, you will see 2 smaller threaded holes that are not being used for anything on the rotor hat.....these holes are for mounting a puller tool to remove the rotor, a harmonic balancer puller tool works excellent for this, you can rent one from Kragen's Auto parts, or you can buy one for like 15-20 bucks. NOTE: the mallet will NOT work for removing the rear rotors like it does for the front rotors.

Then, you will need a Stud removal tool to remove the broken studs from the axle.
Also, buy a spray can of "Liquid Wrench penetrating oil" that will help to penetrate any dirt, rust or grime that may be locking the studs down. Spray the studs generously, and let them soak in the oil for about 30 mins or so.

Good luck!

-Ted

P.S. Why do you only have 4 hours to do this job? You MAY need more time than that if you run into problems.

P.S.S. I am not sure if you can remove the studs without taking off the axle nut to get the hub off, there may not be enough room behind the hub to get the tools in there properly while it is still on the car.

 

You can also use a pair of 12mm bolts to pop the rotor off the hubif it's frozen. Just make sure you use grade 8 or above bolts, and be careful as you work so you don't strip them out. I mashed the ends of the bolts that hold down the rear seat cushions, since those were the least-necessary 12mm bolts I could find when I did my rotors.