Unexplained Brake Pulling Issue Solved

  You’ve tried everything. You’ve checked alignment, replaced the drums, slack adjusters, s-cams and bushings, etc.; and still the driver complains that the truck pulls to the right or left when braking.

   I can feel the frustration coming from the person who has seemingly done everything right - and is still having issues with the brakes on one position.

 You've heard the statement: “You can’t fix what you don’t know is broken.” Meaning, if you can’t see the problem, you probably aren’t going to repair the problem. And when it comes to brakes, it is often what we can’t see that ends up biting us. 

  When I receive questions surrounding single side, unexplainable brake problems, I generally recommend getting a self-leveling cross-line laser to find the issues you can’t see with the naked eye.

   Most technicians think they can visually check for a bent spider. Often, you can’t. And at the end of the day, if you’ve tried everything else, a bent spider is most likely your issue. 

   See the attached Figures A and B. Ask yourself honestly if you could have spotted the alignment issue without the benefit of the laser. (In Figure B, a zip tie is used to extend the visual out past the center of the s-cam head. Note that the laser does not extend through the zip tie. When the laser was set up on the opposite side, the beam continued through the center of the s-cam and through the zip tie.) Now consider the fact that prior to using this laser, the owner had spent a year and a fortune taking this tractor to shops and specialist without remedying the issue. The self-leveling cross-line laser used in these photos was purchased for less than $50.

Brian Beathard

RevHD Wheel End Specialist

Pro-MECH Instructor