About 20 min into drive on back roads , using brakes frequently, noticed shake steering then smell, then smoke from front driver brake. Let car sit 90 min then drove home another way with alot less brake use and had no problem. Car is a 06 legacy. 

Should I assume that the caliper is bad and replace it? Wanted to ask since I really am not sure how to proceed. Thank you.

I'd at least flush the brake system and inspect the pads.  How many miles on the car?

You may have boiled the brake fluid in that caliper.

 

An inspection will tell you if anything is out of kilter.

 

Larry

I had to pry off the caliper and there are 2 pistons , the one I tried to compress is frozen solid. The pads have about 20 % wear.No leaks and the caliper bolts came out easy and where they bolt into compress and return nicely so the caliper was not sticking, the pistons are locked.

ron2368,

 

Seized pistons in the caliper may or may not spell doom for the caliper. IF they can be removed, and IF the pistons and the caliper bores have not been scored, you may be able to resurrect them. But your language telegraphs that you're not a wrencher, so you are best to just replace the caliper and BLEED the entire system flushing out the old fluid.

 

Seized pistons can be removed by replacing the bleed screw with a grease nipple and pumping them out with a grease gun. A clean up of the pistons and bores with 0000 steel wool will show whether they can be saved, if there are no deep pits. If so, clean and lube them with fresh brake fluid and reinsert, providing the seal and dust boots are in good condition.

 

One thing for sure, if one caliper has gone bad, the others are not far behind. They all need servicing (as described) or replacement. When the owner's manual says to flush the brake system every 48 months .... this is the reason why. Good Luck!

The front calipers on this car were replaced about 3 years ago by my mechanic. The car has about 70k miles( its an 06). I picked up a replacement at Advance Auto for 50$ and its seems ok,  My brake fluid is like new on the wheel I bled. I would think that the caliper I removed was not even braking the car since once it froze and the pads wore down , it was useless. Thank you .