Service manual

Rev. A
Groundsmaster 3280--D/3320 Hydraulic SystemPage 5 -- 21
Implement Relief Pressure Test (Using Pressure Gauge)
The implement relief pressure test should be done if a
problem is suspected with the implement relief valve.
NOTE: When conducting the Implement Relief Pres-
sure Test, use a 5000 PSI (350 Bar) Pressure Gauge.
1. Perform steps 1 through 8 of the Charge Pressure
Test (see Test No. 1 in this section). Make sure to use a
5000 PSI (350 Bar) Pressure Gauge.
2. With the engine running at 3200 RPM, move the lift
control lever to the RAISE position and allow the cutting
unit (or implement) to fully raise. Continue to hold the le-
ver in the RAISE position and observe the pressure
gauge. The pressure reading should be from 700 to
1000 PSI (48.2 t o 69.0 bar) as the implement relief valve
lifts.
3. Move the lift control lever to the LOWER position to
lower the cutting deck (or implement) to the ground.
Shut off engine. Record test results.
NOTE: If the implement relief pressure is 700 to 1000
PSI (48.2 to 69.0 bar) and a steering or lift problem oc-
curs, inspect for a problem unrelated to the hydraulic cir-
cuit (e.g. binding steering or lift system components,
debris build--up on/under the cutting deck). Check and
repair other items before continuing with hydraulic tests.
4. If the implement relief pressure is below 700 PSI
(48.2 bar), adjust the implement relief valve in the trans-
mission by adding the required amount of shims from
the shim pack (see Implement Relief Valve in the Sauer--
Danfoss (Sundstrand) 15 Series Service Manual at the
end of this chapter).
NOTE: For every 0.010 in. (.254 mm) of shim thick-
ness, there is an approximate 50 PSI (3.4 bar) change
in implement relief pressure.
If adding shims to the relief valve does not increase
pressure, inspect the condition of the charge pump ger-
otor and internal housing (See Charge Pump Service in
the Sauer--Danfoss (Sundstrand) 15 Series Service
Manual at the end of this chapter).
If the charge pump is in good condition (no scoring,
scratches or excessive wear), the general condition of
the transmission’s piston pump and piston motor might
be suspected of wear and inefficiency. A lack of mini-
mum implement relief pressure could be due to the
charge pump having to direct all flow to the main traction
circuit (piston pump and piston motor).
5. Disconnect pressure gauge from the transmission.
Install pipe plug back in the transmission. Check hy-
draulic oil level in reservoir ( front axle).
Figure 18
2
1. Seat base opening
2. Check valve
3. Pipe plug
4. Implement relief valve
1
2
3
4
Figure 19
FRONT
RELIEF
VALVE
Hydraulic
System