One problem related to suspension torsion bar has been reported for the 1998 Toyota 4Runner. The most recently reported issues are listed below.
I was in reverse and a jolt and pop occurred in the rear passenger seat where my son was seated. He felt it at his feet and all other passengers heard and felt a jolt. When I returned home I crawled under the vehicle and noticed rust and stress cracks on the inside of the rear passenger torsion bar. While applying pressure with my two fingers I pushed through the bottom of the frame rail. The vehicle is not road worthy. My braking problem occurs when I have to stop suddenly in snow or extreme wet road surfaces there is a metal grinding an no brakes. When this occurs in snow I was in 4wheel high. I had no brakes so I put the vehicle in 2 wheel and had brakes. In rain I pumped the brakes until I was able to get brakes. All driving brakes occurred at 35 mph in city driving with no one in front of me.