I have a 1996 jeep cherokee laredo, when I hit the brakes after a long hard ride the whole jeep shakes violently. The dealer I bought it from offered to put new brakes on, is this the problem or should I have something else looked at? Please help!!!

THAT IS A BAD SIGN
AND IS A HANDS ON check
any time brakes do that, its a huge SIGN OF DANGER To you and others.
get off the internet and find hands on, help.

Please have this checked out as soon as possible. Either you, a Mechanic, or an alignment shop, need to check out the front-end and all four points. Something has changed, broke, or is loose and worn out. Check: Ball-joints, wheel bearings, tie-rods, rims, lug-nuts, tires, tire balance, tire inflation, tire tread wear, alignment, U-joints, shocks, and suspension. Let me know if I can be anymore help, good luck.

check for a broken strut or shock

well is the motor shaking or does it feel like the tire/steering is shaking? if it feels like the tire then most likely it is your steering shock stabilizer. this is the shock that is in the front end of the jeep the runs horizontally. hope this helps.

put the key in the drivers door lock it with the key still in the lock unlock it and then pull the key out do this three times that is the factory built in security programing shut off system for jeeps and chrysler

You have two unrelated problems. the power loss can be from a variety of things. What you first need to do with that is have a scan done (many parts stores do that free)...then if you have codes stored, you at least have some direction to go in with that.
The shaking is called death wobble and also has many causes. The most common are bad ball joints or tires that are worn sufficiently so as to not have enough foreward momentum to not react to side loading from bumps. The same tire can still generally pass inspection but is no longer useful on your vehicle (usually with around two thirty seconds of remaining tread measured at the wear bars). Any wear in any of the front end steering components or bushings can also cause wobble...sometimes it is a cumulative effect of slight wear in several places totaling an unacceptable amount of overall play. If you just had brake work or new tires installed, sometimes improper torquing of the wheels can also cause that. If you don't see anything obvious have an experienced jeep tech look at it. It can be dangerous and is nothing to ignore or wait on.

It has this problem at Idle? If this problem is while the vehicle is moving but not at Idle or when you rev the motor check your A frame, Connecting Rods, Tie Rods and Ball joints. You also want to check to loose lug nuts or a bent rim. If it occurs when it sits at idle check the motor mounts and bushings and the transmission mounts and bushings.

I had the same problem and it was a small shock sitting horizontally called the steering stabalizer your something close to that. Eazy fix.

Jason

1996 ,wow its classic its over 10yrs of age ,,,,,,renew it sounds like engine is finished

the simple fix might be the park interlock cable. this locks the shifter unless you press and hold the brake pedal while selecting gears. I've seen and replaced a few of these on several chrysler/dodge vehicles.