Manitowoc Grove RT770E Service Maintenance Manual

Published 8-10-2015, Control# 589-00
This Supplement provides information on performing a Leak
Path Test for A/B Mode, Discreet Stage Control Telescope
Cylinder (RT770 Montan Cylinder - p/n 80035407)
LEAK PATH TEST PROCEDURE
1. Raise and extend boom to appropriate position, 60
degree or higher angle with moderate hook load and at
least 50% T1 and 50% T2 preferred.
2. Allow crane to normalize to ambient conditions;
minimizing thermal drift as a factor.
3. Record ambient temp and perform drift test
measurement for at least 1hr.
4. Record change in lengths of T1 & T2. Record ambient
temp.
5. If start/stop ambient temps are different, factor out
thermal drift; refer to document 6829002741.
6. If leakage drift exists, install valve in each of the
following lines if present:
- Extend (between main directional valve and stage
select valve)
- Retract (between main directional valve and
cylinder retract port)
- Fill Tube (between fill valve and cylinder port)
- Drain (between case drain and tank port on
cylinder)
7. Close all valves.
8. Repeat steps 1 thru 5. Verify zero drift.
9. Open Drain (Tank) valve.
10. Repeat steps 1 thru 5. Drift on T2 only = leaking
pressure relief valve; test concluded. No drift = close
drain valve and proceed to step 11.
11. Open Fill Tube valve.
12. Repeat steps 1 thru 5. Drift = leaking telescope fill valve;
test concluded. No drift = close fill tube valve and
proceed to step 13.
13. Open the Retract valve.
14. Repeat steps 1 thru 5. Drift = Internal seal bypass; test
concluded. No drift = close retract valve proceed to step
15.
15. Open the Extend valve.
16. Repeat steps 1 thru 5. Drift = leaking hold valve(s)
seat(s); test concluded.

Manitowoc Grove RT770E Specifications

General

Brand	Manitowoc
Model	Grove RT770E
Category	Construction Equipment
Language	English