Alright, So I have a problem that I need a little help with. I have a 99 4.0 XJ with 197k miles, 3 inch lift, and 31" Goodyear wrangler duratracs. This evening, I drove up a mountain (not the side, took a road up) and after I came back down I had an issue. Sitting at the light at the bottom, we smelled a gosh awful burning smell, one that I haven't smelled before. There was also a bit of smoke coming out from under the hood. I pulled over to check it out, and I was unable to find a source of the smoke. I could see a little bit hovering in the engine bay, but there was no specific source. There were no signs of fresh leaks. I sniffed around, and the smell was strongest near the brake booster. I am thinking it is something to do with this because I really wasn't taxing the engine at all on the way down the mountain, just riding the brakes pretty good. I also had to bleed the brakes a couple weeks ago because of a caliper install. Not really sure what the problem it, but do you guys have any ideas? Any tests I can do to see if there is a problem with the brakes? I have also noticed a raspy sound that I believe is coming from the power steering pump when I start the jeep up in the cold. It quits after about 30 seconds. After checking everything, I cranked it up and haven't had any trouble yet. I'm at a loss, and any insight would be appreciated. Thanks!

 

The smell was probably coming from the brake pads themselves.

 

That would be my first thought, but it didn't smell like burning brakes, or what has been my experience.