generator12
Senior Chief Petty Officer
- Joined
- Jul 9, 2010
- Messages
- 666
I've got an interesting one on my hands.
I had a four-wheel brake job done - rotors and pads on front and new pads on the rear. Also had the tires rotated.
When I got it back, my ABS function would occasionally operate when stopping in reverse - not every time, but about every third time. Brought it back and they adjusted the pre-load on the bearings a bit, which took care of it. But I also had a sight drift to the right in forward drive, which was judged to be tire-related. Also discovered a speed-related vibration between 68 and 80 MPH. Not consistent - sometimes could feel it in the steering wheel and other moments not. But it seemed involve the entire vehicle. Intensity not related to accel or decel, and would momentarily disappear when topping a hill. The vibration is appears to be at the tire rotation frequency (around 700 RPM), not the driveshaft rotation frequency (around 3400 RPM) Slipped the truck into neutral for a few seconds at speed and this had no effect on the vibration.
Continental replaced the two tires on the front (pro-rated on mileage), and this cleared the steering drift, but not the vibration. The shop dialed the rotors and found no run-out in any direction.
Inspection has revealed no issues with suspension components. All appears good and tight with no abnormal wear apparent. The truck had suffered no trauma of any kind - no huge pothole, no collision - nothing - at the outset of this condition.
Follow-up actions taken:
1. New U-joints, front and rear.
2. Tested with a new set of Goodyears, balanced of course. No change.
3. Rear axles not found to be running out (No load of course, wheels off and spinning)
4. Moved to another shop and he put a complete set of wheels and tires (from a Lincoln) on. Vibration continued unchanged, at wheel rotation frequency. Same indicated speed range.
5. Installed new shocks on all four corners. This appears to have dampened the vibration. Still not quite tolerable, but much improved. That fact appears to point to the wheels/tires as opposed to frame or chassis vibration, but these have been repeatedly balanced at several points in this episode.
I'm unable to identify any shops in the Milwaukee area with the capability of installing accelerometers or other vibration measurement devices, as I hoped to tie one each to the suspension at all four corners to try to isolate a source.
As it stands, the operators of two shops and I are all baffled regarding this situation.
Guys, I'm all ears...! Thanks.
I had a four-wheel brake job done - rotors and pads on front and new pads on the rear. Also had the tires rotated.
When I got it back, my ABS function would occasionally operate when stopping in reverse - not every time, but about every third time. Brought it back and they adjusted the pre-load on the bearings a bit, which took care of it. But I also had a sight drift to the right in forward drive, which was judged to be tire-related. Also discovered a speed-related vibration between 68 and 80 MPH. Not consistent - sometimes could feel it in the steering wheel and other moments not. But it seemed involve the entire vehicle. Intensity not related to accel or decel, and would momentarily disappear when topping a hill. The vibration is appears to be at the tire rotation frequency (around 700 RPM), not the driveshaft rotation frequency (around 3400 RPM) Slipped the truck into neutral for a few seconds at speed and this had no effect on the vibration.
Continental replaced the two tires on the front (pro-rated on mileage), and this cleared the steering drift, but not the vibration. The shop dialed the rotors and found no run-out in any direction.
Inspection has revealed no issues with suspension components. All appears good and tight with no abnormal wear apparent. The truck had suffered no trauma of any kind - no huge pothole, no collision - nothing - at the outset of this condition.
Follow-up actions taken:
1. New U-joints, front and rear.
2. Tested with a new set of Goodyears, balanced of course. No change.
3. Rear axles not found to be running out (No load of course, wheels off and spinning)
4. Moved to another shop and he put a complete set of wheels and tires (from a Lincoln) on. Vibration continued unchanged, at wheel rotation frequency. Same indicated speed range.
5. Installed new shocks on all four corners. This appears to have dampened the vibration. Still not quite tolerable, but much improved. That fact appears to point to the wheels/tires as opposed to frame or chassis vibration, but these have been repeatedly balanced at several points in this episode.
I'm unable to identify any shops in the Milwaukee area with the capability of installing accelerometers or other vibration measurement devices, as I hoped to tie one each to the suspension at all four corners to try to isolate a source.
As it stands, the operators of two shops and I are all baffled regarding this situation.
Guys, I'm all ears...! Thanks.
