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20 ► MHP3 Diesel User Manual
GENERAL
Tests and adjustments should be performed periodically
to ensure the TracHorse is operating at maximum ef-
ciency. Stanley Circuit Tester (P/N 04182) is recom-
mended. This tester can be used to isolate problems in
both the engine and hydraulic system prior to any Tra-
cHorse disassembly.
TESTING THE HYDRAULIC CIRCUIT
The following tests can be performed to ensure that the
hydraulic pump is supplying the correct ow and pres-
sure and that the system relief valve is operating prop-
erly.
During these tests, make sure the engine is warm and
operating smoothly. If test results are not as specied,
refer to the troubleshooting table given in this section for
possible causes.
TESTING THE 5 GPM EHTMA TYPE C CIRCUITS
To test either of the two circuits, proceed as follows:
1. Set both Circuit Control Levers to the OFF (down)
position. Push the Combiner Knob IN to separate
the two circuits.
2. Connect the Stanley Circuit Tester across two hose
ends (where the tool would normally be connected)
of one circuit.
3. Fully open the tester restrictor valve (counter clock-
wise).
4. Start the engine and allow it to run until warm.
5. Pull the engine throttle control completely OUT so
that the engine is running at full RPM.
6. Move the Circuit Control Lever for the circuit to be
tested to the ON (up) position.
7. With the engine at high speed, the test ow gauge
should read 4–5 gpm/15–19 lpm.
8. Slowly turn the restrictor valve clockwise while
watching the pressure gauge. The ow rate should
stay at 4–5 gpm/15–19 Ipm as the pressure gauge
reaches 2100–2200 psi/148–155 bar.
9. At 2100–2200 psi/148–155 bar the relief valve
should begin to open. The pressure at which the re-
lief valve just begins to open is commonly referred
to as the “cracking pressure”. At the “cracking pres-
sure”, the ow rate should start to drop because the
relief valve is allowing uid to bypass to the hydrau-
lic reservoir. The “cracking pressure” is preset at the
factory and if it is not within the above range, the
relief valve must be reset as follows:
a. Access to the relief valves can be gained
through the front of the dash behind the two
plugs (item 54, major assy). Use a socket and
ratchet wrench to loosen the locknut on the re-
lief valve.
b. Use an Allen wrench to adjust the relief valve.
Turn clockwise to raise the pressure and coun-
terclockwise to reduce the pressure.
c. Tighten the locknut and test for 2100–2200
psi/148–155 bar as described above.
d. Repeat the above test with the hoses and tester
connected to the other circuit.
TESTING THE 10 GPM EHTMA TYPE D CIRCUIT
The 10 gpm circuit is formed when the combiner knob
is pulled out and both circuit control levers are set to the
ON (up) position. This allows the output of both pump
sections to be combined at one set of ttings to provide
10 gpm/38 Ipm ow to a single tool. To test the circuit,
proceed as follows:
1. Perform Steps 1 through 5 under “Testing The 5
gpm EHTMA Type C Circuits”. Make sure a tool and
hoses ARE NOT CONNECTED to the other tool cir-
cuit.
2. Pull the combiner knob OUT to combine the two cir-
cuits.
3. Raise both control levers to the ON position.
4. With the engine at high speed, the test ow gauge
should read 9–10 gpm/34–38 lpm as the pressure
gauge reaches 2100–2200 psi/148–155 bar.
5. Perform Step 9 under “Testing The 5 gpm EHTMA
Type C Circuits”.
• The track tension is adjusted with the unit lifted off
the ground. Between the drive wheel and front idler
wheel, there are 3 smaller rollers.
• Once the unit is lifted off the ground, adjust the track
tension to achieve 3/8” to ½” sag below the center
small roller.
ADJUSTING TRACK TENSION
TESTING & TROUBLESHOOTING