QuestionThe vacuum hose seems to collapse keeping the wheels locked in. I have to pull the hose off to run in two wheel.The diagram shows a check valve in the vacuum source line. What is the reason for this? There is not one on my truck.I replaced the source hose and found a tee in the line. I thought this was causing a vacuum loss so I didn't put it back on. This is a 1985 Chevy S-10. Thanks in advance.
AnswerTom,
Sounds like your line, is not a vacuum line. A line designed for vacuum shouldn't collapse. The vehicle doesn't develop enough vacuum to collapse a vacuum line. As far as the tee goes, if one was in line, then it should have been connected to something. If it was open, you would, definitely, have a vacuum leak. Actually, just pulling the vacuum line off, should not shift the front end out of 4-wheel. I'm not real familiar with Chevys, but most of these systems work off of a vacuum switch, located on the transfer case, that switches the vacuum from one line to another, allowing it to shift in and out of 4-wheel drive.
I would suggest that you purchase a repair manual for your rig, and trace out the vacuum lines, and replace any that seem to be collapsing with new lines. Chilton's or a Hayne's manual can be purchased at most auto parts stores for $20. They have a lot of information on basic trouble shooting, and repairs, including a list of special tools that may be needed for a specific job, nut sizes along with torque settings. These manuals are designed for a year or range of years for specific vehicles, and are invaluable if you are planning on doing any repairs, or maintenance yourself.
Carl
