|Posted by [email protected] on August 16, 2012 at 9:00 PM|
Last week I had a call from Ft Wilderness to come down and repair a coach whose "Auto Park" was malfunctioning. Auto Park systems are a hydraulic system that links to either a set of brake calipers on the rear of the vehicle, or directly to the transmission. In this case it was on a freightliner chassis and was connected to the transmission. The system is basically a simple pump that pressures up a line that pushes a diaghram pressure valve to push a cable to release the parking break on the transmission housing.
When I got there I searched everywhere for the reservoir to check the fluid. After looking for awhile and tracking the lines back up to the front of the motor, I found a small reservoir hidden behind a gob of wiring harnesses. It was completely dry, so I refilled the reservoir and we started the engine. The pump engaged and quickly pumped all the fluid right on the ground. The diaphragm pressure switch was faulty. It was 2pm on a sunday and these people were already overdue to be headed back to south Florida. They asked if I could disengage the "auto park" assembly so at least they could drive home.
I released the pressure arm so that they could drive the coach. The only thing that this system does is, pulls the clutch plate out of sync so that the tranny doesn't engage. They were very happy and I helped them pack up so that they were not charged for another night. The Worcesters gave me a thumbs up..