I assume your referring to semi trailers. Vacuum brakes were used into the late 40's/early 50's and them the industry standardized on full air. Does your tractor have air brakes? If not then it would be very difficult to change it to full air and very, very expensive.


1953 Chevy 5-window 3100
In the Stovebolt Gallery
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Dave
Engine & Driveline Moderator

If you can't make seventy by an easy road, don't go. ~~ Mark Twain