Intermittent pull - left under power, right on braking

[BlackJeep]

It's been about 6 weeks since I finished dual axle swaps, replaced all steering components, swapped lift, MML, and generally rebuilt the underside of the Jeep. All ball joints and bushings were replaced in the process. I'm still in what I consider the "building confidence that I didn't forget something important" stage - short trips, no interstate, keeping it under 40.

On the way home from a 20 mile-or-so drive last night I noticed that the Jeep was pulling slightly to the left, which it hadn't been doing since I got the pinion angles worked out and did an alignment about a month ago. Maybe it was my imagination, but it seemed to get slightly worse as I continued to drive home. Then when I got to a light it pulled hard to the right under braking. I drove the last mile or two playing with that: gentle pull to the left under power, and harder pull to right under braking. The pull under braking was so noticeable that I could idle forward 5-10 feet, hit the brake hard with my hands off the wheel, and watch the wheel turn 20 degrees to starboard.

Any thoughts on what to check/adjust/tighten/replace/curse at?

 

[g.hayduke]

Sounds like you probably have an issue with the brakes for sure causing the pull to the right and possibly the pull to the left.

One possible explanation: If the left caliper is dragging, that side will heat up while driving & cause a slight pull to the left. The heat from the dragging caliper can basically make the brake on that side "fade" and have little stopping power. Then when you apply the brakes, only the right side is really working, so it pulls to the right. If this is the scenario, the left front wheel will be noticeably hotter than the right side.

I have experienced this exact scenario a time or 2.

 

[toximus]

If it's consistently those directions, it's a seized caliper. Bleed them before replacing. I'd replace both sides at the same time.

 

[BlackJeep]

Many thanks guys. That makes perfect sense. Now I know how to start getting into it this weekend.

 

[MaloStapalo]

Also try to test on flat areas like parking lots. Roads have a natural slope built into them and the road wear can cause our tires to pull with the slope.