On my 02 Mack MR my front brake makes a bang when i stop hard and now it is starting to stick afterwards. If i take a hammer and tap the arm it pops back out. I need to pull the tire and inspect but thats another question: Do i need a 1" impact wrench to get the tires off?  

I would bet not.  A good 3/4 should do the job.  I have a 1/2 that is rated at 1600 ft pounds that has handeled everything I have thrown at it.  

Goose, maybe the key is "Good" 3/4" and lots of air. I don't know i haven't tried one.

Sounds like the cam may be short on grease, or the springs on the shoes are weak/broken.

Is the cam the shaft that goes in to the chamber? 

i would guess your s cams are rolling over brakes worn out need to address that quickly

The cam is the short splined shaft that the slack adjuster is mounted to.  It is inside a tube leading to the wheel hub.  (This diagram is more for a trailer axle, but it gives a decent overview - note, the s-cam shaft isn't inside a tube, like on your front wheel.)  It may also be like Beast says, if the S-cam is starting to 'over cam' - meaning that the brakes are so badly worn, and the adjustment is as far as it can go, the rollers are on the extreme radius of the S-cam.  You have an ispection port (at about the 8 o'clock position) in the brake shield to check the thickness of the brake shoes, they must be a minimum of 1/4" - but even that is too thin in my opinion.  1/2", is my standard, but it also depends on how severe your braking is.  At inspection time, I liked to see more than 5/8", then I was pretty much assured that it would make it to the next inspection.

Very true,front shoes are getting thin.This is common before it cams over,slack adjusters are at the end of travel.

Thanks Guys. I was in International falls last night for a stay over pump job (did 400 yds) any way on the way home today i was thinking.. Are the front brakes on a 02 Mack self adjusting? Could it be that i am so out of adjustment this problem is occuring?

P.S Doug, GREAT PHOTO diagram. 

I wouldnt think so , but if you know how to adjust the brakes , give it a shot, i have some so-called self adjusting brakes, I still adjust my brakes monthly, I would think depending on the miles on the truck in question, me just going by year model it may be time for a brake job.

I adjusted them today and it helped some with the preformance but they still roll over if pushed hard. I also called Mack and asked, sounds like you guys are right its time for new shoes also a spring and roller kit. I checked the pad thickness and they are about 3/8" at best. Now i need a 3/4" impact wrench. Any advice as to what is the best kind or brand? Air Cat, or ingersold rand, Matco? Maybe it doesn't matter?

Well, i got my brakes looked at and diagnosed: First of all, one day i had a flat tire on a back drive tire and also at the same time a major leak on the axel seal. I took it to Catco truck repair on the way home (i had a job in the AM). They fixed the seal and it turns out i had a bad non working brake on the same drum. They put on a new drum and shoes while i watched (will do the rest my self). 

The mechanic said most people (me included) do not adjust there brakes properly. THE WAY to do it is: in the morning while airing up your system give two hard stomps then one long hold it stomp. What this does is the first two stomps tighten and the third releases. Also it is possible to adjust auto brakes manually you do it the same as the old type just only back them off a small 1/8 turn or so. My rear brakes had an 1/8 inch space and the front were doing all the work there for rolling over the s cam. This winter after i get a 3/4" impact set up, i will put on all new drums and shoes.