Grove Published 11-10-2014, Control # 524-00 4-15
RT880E SERVICE MANUAL BOOM
4. Ensure all electrical components disconnected during
removal are operating properly.
Inspection
Visually inspect telescoping sections for adequate lubrication
of all wear surfaces. Observe extended sections for
evidence of cracks, warping, or other damage. Periodically
check security of boom wear pads. Check boom nose
sheaves for security and freedom of movement.
Should boom chatter or rubbing noises in the boom occur, it
will be necessary to lubricate the telescope cylinder wear
pads. Refer to Boom, page 9-23.
Boom Alignment and Servicing
Refer to Boom, page 9-23 for the proper lubricant.
Boom alignment is done as the boom sections are being
assembled into one another. A check and fine adjustment is
as follows.
1. Fully extend the boom horizontally.
2. Lubricate the boom bottom channels and top corners.
3. Adjust the front top wear pads such that wear pad is just
touching or is no more than 2 mm (0.078 in) from con-
tacting the next section both at the top and side surfaces
of the top radius.
4. Retract and extend the boom; check for the high point
where the boom has brushed the wear pads at the wid-
est point.
5. Retract the boom sections to align the high point on the
boom section with the adjacent wear pads.
6. Add or subtract shims as necessary.
7. Attach a weight and extend the boom full length. Check
for side deflection.
Example: If the boom deflects to the left, the top left wear pad
would have shims added and the top right wear pad would
have shims removed.
Cam Operated Check Valve Adjustment
There are two cam operated valves mounted on the back of
the inner mid section. When the boom is fully retracted or the
inner mid is fully extended, the valve on the right side of the
boom is held open to supply flow to the lower telescope
cylinder. When the inner mid is fully extended, the valve on
the left side of the boom opens to supply flow to the upper
telescope cylinder. For a short period of time, both valves are
open because the lower cylinder is fully extended before the
upper cylinder starts to extend. As the outer mid starts to
extend, the valve on the right side closes to shut off the flow
to the second stage of the lower cylinder.
1. Ensure the extend and retract cables are adjusted.
2. Extend boom out so that inner mid section is fully
extended and outer mid is bottomed out on stop block of
inner mid.
3. Access the check valves through the hole on right side
of base section.
4. Left side valve (extend side): Adjust nuts to move the
trigger weld until it just makes the pusher weld contact
the valve stem on the cam valve. Move nuts until the
pusher weld depresses the valve stem of the cam valve
(10 mm). Tighten the nuts.
5. Right side valve (retract side): through the access hole
on right side of base, tighten the bolt until the pusher bar
contacts the valve stem on the cam valve. Adjust bolt to
depress the valve stem of the cam valve 0.4 in (10 mm).
Tighten the nut.
Stop Block Adjustment
Add or remove shims as required so that stop blocks on a
given boom section (both sides) bottom out on the stop
blocks of the next section at the same time.
Front Upper Pad Adjustment
1. Using setscrews, adjust front upper wear pads so that
the wear pad is just touching or is no more than 0.07 in
(2 mm) away from contacting the next outer section at
the side surfaces, and is 0.15 to 0.23 in (4 to 6 mm)
away from contacting the next outer section at the top
surfaces.
2. Lock setscrews in place with locknut.
3. Tighten capscrews until pad support plate is held in
place against setscrews.
Read Side Wear Pad Adjustment
1. Using shims, adjust wear pad so that the wear pad is
within 0.07 in (2 mm) from the side plate of the next inner
section. Equal number of shims should be on both sides.
CAUTION
When extending and retracting the boom during
alignment, movement should be stopped if a restriction is
encountered, and wear pads adjusted as necessary to
provide free travel of the affected boom section(s).
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