REBUILDING
THE MODERN HYDRAULICS NON-SPRING RETURN CRIB JACK
STEP
1: Clamp the jack in a sturdy vice
1/3 of the way from the jack top.
STEP
2: With the coupling pointing
straight up, use a large screwdriver and a hammer to pry the seal in the top of
the jack out. You will be
discarding and replacing this seal with a new one.
STEP
3: Remove the snap ring that is now
visible at the top of the jack cylinder.
Step
4: Remove the coupling from the side
pipe on the jack.
Step
5: Pull the piston from the cylinder
barrel, use the screw top partially screwed into the piston if necessary to get
a good pull on the piston.
Step
6: Remove the cylinder from the vice
and wrap the piston the piston with some type of protection and clamp it in the
vice.
STEP
7: Use the proper wrench to loosen
and remove the nylock nut that holds the washer, cup seal, and bronze bushing
onto the piston.
STEP
8: Clean all parts in a parts
cleaner, drying everything thoroughly.
STEP
9: Remove the O-ring from inside the
bronze bushing and replace it with a new one.
STEP
10: Reinstall the bronze bushing on
the piston after greasing the O-ring. Install
the new cup seal and the steel washer, Screw the jack top into the piston, and
clamp the head of the jack top in the vice.
Reuse the nylock nut, and tighten it
onto the piston with the proper wrench. Be
sure to get it tight! To break the
piston loose from the jack top, just use to wrench to try loosening the nylock
nut. The nut should stay tight to
the piston and the piston should come loose
from the jack top.
STEP
11: Grease the cup seal, and slide
the piston assembly into the jack cylinder.
With the piston partially in the cylinder, slide the top bronze bushing
over the piston and into the top of
the cylinder.
Slide the piston all the way into the cylinder, and install the top snap
ring. Install the coupling, and test
the cylinder by putting it under a load and pressurizing it.
IMPORTANT: DO NOT TEST THE
JACK BY FULLY EXTENDING IT! YOU WILL
DAMAGE THE JACK! Install it under a
heavy load. If the jack does not
leak or lose pressure, install the top wiper seal with a driver such as a large
socket.
YOU’RE DONE!