Posted 12/12/2018 18:47 (#7167097 - in reply to #7167067) Subject: RE: 1988 Freightliner Tandem Axle Semi
Madision County, IL
During the pretrip you are required to check the trailer and tractor spring brakes by putting the tractor in gear and trying to pull forward. Trailer spring brakes hold the tractor in place.
When tractor spring brakes are set and trailer is released, engine power overcomes the spring brakes.