1985 PT40 Cruise Problems, better than a roller coaster ride

[GARY MINKER]

If you have a pre 1988 Bendix Cruise and you are driving along and suddenly notice that your cruise is stuck at full throttle, you are not alone. Your seat will pucker when you realize the on/off switch will not disengage your cruise throttle body and you are hurtling down the highway. In the 5 times it happened I was able to diagnose that when you apply the brakes, the pressure over rides a safety valve dump on the cruise throttle body and you can bring the coach to a stop and shut down the engine. Once the air pressure is alleviated, the valve snaps back to place for another scare at an unknown interval. It is pretty exciting to let go of the brake and see the engine come back to full 20 pound boost pressure. The culprit turned out to be sticking valves on the Bendix back board. The maintenance manual states that these valves should be cleaned at regular intervals. They are not kidding. I recommend at least every 20 years or 100,000 miles. Florida Detroit Diesel in Fort Pierce, Florida is the place to go. Mike the Svc Mgr and Gordy the Tech are kings. If anyone knows who is re-habbing the Bendix Controllers, please let me know. Thanks Gary