Im having a problem with the brake on my tractor.（我有一个问题在我的拖拉机制动。）.pdf

I’m having a problem with the brake on my tractor. A quick look at the history of the braking systems reveals some interesting innovations. In 1965, neither the 130 or 180 Case tractors came with any sort of brake on them. There was no parking brake and no “operating brake” like we are familiar with in our automobiles. The Operator was expected to use the travel lever to stop the tractor. Interestingly enough, the very first Colts built in 1963 offered an OPTIONAL drum brake but this was dropped in 1964. In 1966, a “hydraulic brake” was developed for the Case 150 and 190 as well as the 2310,2510 and 2712 Colt models. This “hydraulic brake” was actually a foot operated control valve that was bolted over top of the drive motor ports. If you stepped on the brake pedal, the valve began to close off both ports of the hydraulic motor, thus preventing oil from exiting or entering the motor. When the pedal was fully depressed, the valve closed 100 percent, thus locking up the drive motor 100 percent. The hydraulically locked drive motor prevented the gears in the trans-axle from rotating and likewise the rear wheels were prevented from rotating as well. The major downfall to this method was that the brake worked only when the trans-axle was engaged in either high or low range. If the operator decided to shift out of high range and go to low range on the crest of a hill, he or she better hope that the tractor did not begin to roll while the trans-axle was momentarily in neutral. If that happened, the hydraulic brake would have no effect on stopping the tractor because it was now mechanically disconnected from the trans-axle due to the shift lever being in neutral. This hydraulic brake continued to be used on the 1967 155 and 195 models along with the early 1968 155 and 195’s. By the time 1968 arrived, a new trans-axle began to appear on the 155 and 195’s that sported mechanically operated disc brake ass