XJ wont stop on snow!!!!

Ok,,,,i cant believe i need to even address this issue in a Jeep...buthere goes. There is like not even .5inch of snow on the ground and the Jeep wheels lock up! (91 XJ). so i mean with like one little tap on the pedal i am sliding. I poked my head outside and noted that the front locks up immediately, and the rear doesnt seem to lock up at all. so any ideas?

bald tires?

brakes out of adjustment?

tires i think are ok, there is about 1/8-1/4 tread left. as for the brakes in or out of adjustment, i dont know....and i thought i was supposed to have ABS. i just wonder why the rears dont lock up. also, when i had the emissions done, the guy said the rears were not getting any braking action...and i dont know how to fix that.

Yours is a 91, your ABS may be shot. Mine is, and im glad. I would never want ABS to kick in on iced roads, let alone dry ones.

Proportioning valve could be bad, rear wheel brake cylinders could have seized, bad rear break shoes (or out of adjustment), just gotta go around and eliminate stuff one by one, first jack up the rear end and spin a tire, hit the breaks and see if it stops spining, if each wheel stops, then your cylinders are probably ok, then I would see if there is any adjustment to be made, then possibly go to the proportioning valve (also, do a full fluid flush and make sure ALL of the air is out of the lines)

Adjusters freeze up sometimes. If your brakes get better after pumping them a few times, it´s usually a sign there is some air in there (often in the rears). Brakes are an emergancy fix type thing, don´t let them go until it´s too late.
Any tire not marked MS is going to do poorly, when they are cold. Even many of the MS tires are pretty much usless in the snow or ice, even though they don´t get as hard in the cold.
1/8 th inch of tread is going to get plugged up with snow pretty quick. If snow is a regular thing where you live, I´d think about getting a set of tires with some serious tread. Winter retreads, are becoming more popular, they make them with a really soft compound and town and country type tread. They usually only last a couple or three years, but work well.
Four wheel drive is a funny thing, it pulls well in the snow, but doesn´t stop any faster than most normal cars. Every year, during the first snow, I see some guy in a 4X, passing everybody on the road. Usually end up passing him (wraped around a guard rail) after a few miles.

sounds to me like you think that 4 wheel drive has something to do with braking. It doesn't.

If the road is slippery nothing but good snow tires or studs are going to help you.

As for the brakes I would redo the whole rear braking system. Total for drums, shoes, wheel cylinders, and the misc parts should run you about $125. Before you do that I would pull the drums off and take a look at the shoes and stuff. You can easily check to see if your wheel cylinder is frozen by lightly pressing the brake while watching the cylinder for movement.