Hi guys. As a side note, this can also be caused by worn parts in the suspension system. Specifically the track bar and the eight control arm bushings. A potential clue is if the steering wheel doesn't move, or stays centered, when the brake pull occurs, it means the front axle is shifting sideways during braking. Since the spindles move sideways with the axle housing, but the steering linkage doesn't, the relationship causes the spindles to turn to one side. The steering linkage doesn't shift so the steering wheel doesn't either.
If the pull is caused by the brake system, that will usually tug on the steering linkage causing the steering wheel to turn. A lot of larger trucks have been having this problem since the mid '90s. Besides the control arm and track bar issue, we've found the brake rotors must be exactly the same thickness and same speed of cut on the brake lathe. I ruled that out since the rotors are new, but to show how critical this is, I was involved with two lemon-law buybacks at the dealership, and both problems occurred right after a proper, professional brake job had been performed. In the first one, after following the 32-page service bulletin, it came down to the rotors had been properly machined, but one was.020" thinner than the other one. That would have been completely insignificant on any other trucks up to that time, but machining both rotors lightly to the same thickness solved the pull. The second one was brought to me because I solved the first one. That one had only.007" thickness difference in the rotors. That's the thickness of two sheets of paper on a rotor 1 1/4" thick.
The thickness difference was causing temperature to rise faster in one rotor and that changed the coefficient of friction between them causing one to grab harder. You'd get about eight fairly hard stops in quick succession with no sign of a pull, then the next one would throw you onto the sidewalk or into the other lane.
If the track bar is causing this pull, you may not find that with a quick visual inspection, but that is the place to start. The end attached to the frame on the driver's side uses a standard ball and socket, just like is found on tie rod ends. Watch the relationship between that stud and the socket while a helper quickly moves the steering wheel back and forth about 1/8th turn each way. Look for the slightest perceptible up-and-down movement. If you can't see any, you'll need to do the proper check with a dial indicator. As I recall, Chrysler allows up to.080" of movement before the bar must be replaced, but that is unrealistic. That little free play allows the axle housing to wander left and right causing an irritating steering wander. I've solved that complaint multiple times by replacing a track bar that had as little as.030" up-and-down movement. That might sound like a lot, but that could only be detected with a dial indicator. If you notice you have to constantly correct the steering at highway seeds, that track bar is the best suspect.
Monday, May 10th, 2021 AT 6:53 PM