Schwing SP 750-18 - Hoses and Fittings; Torque Specifications; Welding Precautions; Adjusting Relief Valves

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Maintenance
SP 500 / 750-15 / 750-18 / 1000 / 1250 Operation Manual
Keeping your machine in good working condition re-
quires regular maintenance. There are two kinds of
maintenance: preventive and scheduled. Preventive
maintenance will help you avoid unnecessary repairs,
but eventually even well-maintained machine parts
wear out and require repair or replacement.
Scheduled maintenance needs to be done on a time-
ly basis. That may be daily, weekly, monthly, quarter-
ly, semiannually, or annually. It is a good idea to make
a checklist that will tell you what maintenance is due
and when. Keep accurate records of maintenance per-
formed and when the work was completed.
Hoses and Fittings
Schwing uses metric ttings and hoses with metric
threads on the couplings. There are six sizes of tubes
and ttings and six sizes of hoses, all measured by di-
ameter.
All block threads are metric or BSPP.
Hose
Size
Hose ID (mm) Connects with Fitting
and Tube Size
8 8 12
13 13 16
16 16 20
20 20 25
25 25 30
32 32 38
Tube and
Fitting
Size
Tube and
Fitting OD
(mm)
Connects
with Hose
Size
Tube and
Fitting ID
(mm)
12 12 8 8
16 16 13 13
20 20 16 16
25 25 20 20
30 30 25 25
38 38 32 32
Torque specications
When performing maintenance that requires remov-
al and replacement of bolts, you must adhere to the
torque specications for those bolts.
The graph below demonstrate what happens to a bolt
if it is not properly torqued. The dashed line represents
the pres-tress or tightness of the bolt. As the device that
uses the bolt goes through its normal functions, the bolt
in Example A, which is not tight enough, gets stretched
and relaxed with every duty cycle, because the bolt is
pres tressed under the maximum force of the cycle. In
Example B, the torque on the bolt has been raised to
the proper level, which is more than the maximum force
of the duty cycle, so the bolt doesn’t ever feel the cy-
cle. In this example, bolt B would last much longer than
bolt A. The torque specications for bolts used on this
concrete pump are found in the Appendix section of this
manual.
Time
Force
A
Time
Force
B
Welding precautions
To avoid possible electronic component damage, check
the owners manual of the truck to see if anything other
than the battery must be disconnected prior to welding
anywhere on the unit.
Adjusting relief valves
Take care when raising relief valve pressure settings. In
extreme cases, this can cause hoses or ttings to burst
or other components to fail. To be safe, you should be-
gin the adjustment procedure by turning the adjustment
device to the lowest possible setting, and then bring the
device back up to the proper setting.