a. Clean the dirt off of all component and lines between t hoist pump and the reservoir.
b. Start the engine, engage the engine-driven PTO, shift both the main and the auxiliary box transmissions into
neutral, pull the diamond shaped yellow knob to set the truck's emergency/parking brakes, open the hoods to get rid of
some of the engine fan air blast.
c. Equip your buddy with a creeper, a trouble light, a mirror, a pump type oil can with OE or SAE -10, -20, or -30
weight oil, and send him under the truck, As you hoist the dump body by speeding up the engine to about 1000 to 1500
RPM and move the hoist control lever to "HOIST" position, have your buddy squirt oil around each connection of the
components and potential source of air leakage from the hydraulic reservoir to and including the hydraulic hoist pump.
With the body going up, have your buddy look for telltale signs of the squirted oil, on the outside, being sucked into
leaking joints, instead of normally dripping around the outside of tightly sealed joints. Use the mirror and trouble light to
check the top and sides of all connections and components.
d. Tighten those leaks that can be corrected by tightening. Repair or replace those components where leaks cannot
be stopped by tightening. Rather than tightening to the point of stripping threads, disassemble, clean, and repair parts
that further tightening might damage. Be especially wary of tubing and nipples having deformed surfaces, bends, and
5. Next, air can get into the hydraulic system through oil being churned and foaming in the hydraulic reservoir, so watch
your operation during your dump trucking jobs. Don't be in such a hurry to dump your load that you exceed 1500 RPM
engine speed, exceed the lowest dump angle needed to clean the body, or let the body back down in an uncontrolled,
almost freefall manner. All these actions foam the hydraulic oil and will cause someone having to get up on top of your
nice clean cab with their muddy shoes and bleed oil all over your truck to get the air out. Commercial dump truckers say
you won't have to bleed the hoist cylinder more than one or two times a year, if you keep a tight suction line and operate
your dump cycle slow enough so you do not get air/oil foam into your dump hoist hydraulic system.