Figure 12 illustrates the maximum (absolute value) friction torque, minimum (absolute value) peak friction  torque, minimum peak torque at -135°C, and the difference between the maximum friction torque and minimum peak torque for each bushing test. Bushing Friction Torque Comparison 131 32 3299 77 42 4235160 77100 83189 56117133159 24128135 58 203038307 87237 221 050100150200250300350 Maximum Friction Torque Minimum Peak Torque Minimum Peak Torque (-135C)Max DifferenceFriction Torque (N m)MoS2 based bonded film with silicate binder coated SS Bushing vs. Al MoS2 based bonded film with phosphate like binder coated SS Bushing vs. Al Polyamide-imide Bushing vs. Al Polyimide Bushing vs. Al Braycoat 601EF Greas eplated Polyamide-imide Bus hing vs . Al MoS2 based bonded film with phosphate like binder coated SS Bushing vs. Ti Bare SS Bushing vs. Al Figure 12:  Bushing Friction Torque Comparison  One striking result of the bushing test series was the wide variation of friction torque over the test  temperature profile. This variation was somewhat surprising as the coefficient of friction values for both  bonded films and polymerics are not considered to be highly sensitive to temperature variation. If the coefficient of friction values were stable over temperature another mechanism must have been  responsible for the friction torque variation during the testing. One possibility is that the mismatched, CTE induced, variable gaps between the shaft, the bushings, and the housing changed the contact geometry enough over temperature to produce the torque variation. Another possible cause for the wide friction torque variation over temperature would be a test setup  related systematic error. The setup for this test series was complex and involved the interaction of several  large elements over a significant temperature range. The turnbuckle adjustments made to maintain a  constant load on the driveshaft may have inadvertently altered the desired loading on the bushings.  Although this is a possibility, the adjustments would not explain all of the torque variation over temperature. In addition to the torque variation over temperature one sample also encountered an unexplained torque  anomaly during testing. About midway through the cold dwell during the silicate binder MoS 2-bonded film  test a torque ripple event occurred. The friction torque climbed steadily for several hundred cycles until  peaking then abruptly self-correcting. It is difficult to definitively state what the cause of this event was  given that the samples were not accessible at the time. That being said it was clear after disassembly of the pivot that a large amount of wear debris was generated during this test. The large volume of wear  debris in the pivot could have shifted during the test and partially restricted the motion of one of the  bushings. After some period of time the wear debris blockage could have cleared returning the assembly  to a pre-event state. It is unknown whether this was an isolated event during just this test or this would be  a repeatable behavior. The limited number of samples tested during this series does not provide any statically significant data to assess the repeatability of the behavior. None of the other samples exhibited  this behavior during testing. A review of the summary chart in Figure 12 illustrates the wide maximum friction torque variation between  different bushing systems. The best performing bushing system with respect to maximum friction torque and maximum torque difference appears to be the “phosphate-like” binder MoS 2-based bonded film  93