228 and 248 Skid Steer Loaders Machine Systems Caterpillar

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Personal injury or death can result from improperly checking for a leak. Always use a board or cardboard when checking for a leak. Escaping air or fluid under pressure, even a pin-hole size leak, can penetrate body tissue causing serious injury, and possible death. If fluid is injected into your skin, it must be treated immediately by a doctor familiar with this type of injury.

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Sudden movement of the machine or release of oil under pressure can cause injury to persons on or near the machine. To prevent possible injury, perform the procedure that follows before testing and adjusting the power train.

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NOTICE
Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting and repair of the product. Be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component containing fluids. Refer to Special Publication, NENG2500, "Caterpillar Tools and Shop Products Guide" for tools and supplies suitable to collect and contain fluids on Caterpillar products. Dispose of all fluids according to local regulations and mandates.

Note: All of the tests are run with the hydraulic oil at a temperature range of 38 to 65°C (100 to 150°F).

The tests for the hydraulic system should be done in the following order. In order for the hydrostatic system to function properly, each component in the system must be set to the correct specifications. Some components must be set prior to the testing of other components. A component that is not set properly will have an impact on other components in the system.

It is not advisable to bypass preceding tests. Do not perform a test before the tests that precede that test have been done. The following chart lists the equipment that is needed to perform testing on the hydrostatic system. Equivalent tooling may be substituted. You will need additional wrenches, shop equipment and tools. You may need additional fittings.

Clearly mark all of the hoses and the corresponding pressure gauges, when the hoses are installed. The hoses and the pressure gauges will be used multiple times in the testing and adjusting procedures.

Throughout the entire testing procedure, MA pressure refers to the hydraulic oil pressure in the forward hydrostatic loop. MB pressure refers to the hydraulic oil pressure in the reverse hydrostatic loop.

Test A

Baseline for the Hydrostatic System

The test A must be performed in order to establish a starting point for the hydrostatic system. After this test has been completed, two objectives will be established. The machine will be able to be tested. A baseline for the remaining tests will have been established.

Table 1

Required Tools
Part number	Description	Quantity
6V-4143	Coupler Assemblies	7
177-7860	Hose Assemblies	7
6V-3989	Unvalved Nipples	9
6V-3965	Valved Nipple Assemblies	4
8T-0855	Pressure Gauges	2
8T-0853	Pressure Gauges	2
8T-0854	Pressure Gauge	1
6V-3121	Multitach	1
9U-7400	Multitach	1
8T-0861	Pressure Gauges	2
8T-0857	Pressure Gauges	2
5P-2937	Adapter	1
6V-3966	Fitting	1
5P-3413	Pipe Sealant	1
3J-1907	O-Ring Seals	4
1U-6602	Photo-Tachometer	1
6E-5060	Caps	2
8T-8902	Tee	1
6V-9510	Face Seal Plugs	4
6V-9831	Caps	4
7J-9108	O-Ring Seals	4
6V-9511	Face Seal Plugs	4
6V-9832	Caps	4
6V-9746	O-Ring Seals	4
4C-8765	Absorbent Pads	10
3J-7354	O-Ring Seal	1

1. Move the machine to a smooth horizontal location. Move the machine away from other machines and personnel. Lower the lift arms to the ground. Stop the engine.

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Illustration 1	g00560554
Use wood blocks to elevate the machine.

2. Use wood blocks to elevate the machine. The wheels may not touch the ground.

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Illustration 2	g00561338
Remove the ROPS mounting bolts (1) .

3. Remove the two bolts and the two nuts (1) that mount the ROPS to the frame. Raise the ROPS and lock the ROPS into position.

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Illustration 3	g00699501

4. Remove the plate. The plate contains the warning signs.

5. Clearly mark all of the hoses and the corresponding pressure gauges, when the hoses are installed. Secure the hydraulic lines so that the pressure gauges can be viewed by the operator during the test.

6. Install one 6V-4143 Coupler Assembly to each end of the 177-7860 Hoses.

7. Install one 6V-3989 Unvalved Nipple to 8T-0855 Pressure Gauge.

8. Install one 8T-0855 Pressure Gauge with range 0 to 4000 kPa (580 psi) to one end of the 177-7860 Hose .

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Illustration 4	g00698824
Charge pressure tap (2)

9. Install the other end of the hose to the charge pressure tap (2). The charge pressure tap (2) is located on the interlock manifold valve and mounting. The interlock manifold valve and mounting is located on the upper left side of the machine. Look for the accumulator on the interlock manifold valve and mounting.

10. Install one 6V-3989 Unvalved Nipple to 8T-0855 Pressure Gauge.

11. Install one 8T-0855 Pressure Gauge with range 0 to 4000 kPa (580 psi) to one end of the 177-7860 Hose .

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Illustration 5	g00698828
Speed sensing pressure tap (3)

12. Install the other end of the hose to the speed sensing pressure tap (3). The speed sensing pressure tap (3) is located on the interlock manifold valve and mounting. The interlock manifold valve and mounting is located on the upper left side of the machine. Look for the accumulator on the interlocking manifold valve and mounting.

13. Install one 6V-3989 Unvalved Nipple to 8T-0853 Pressure Gauge.

14. Install one 6V-3989 Unvalved Nipple to 8T-0853 Pressure Gauge.

15. Install one 8T-0853 Pressure Gauge with range 0 to 400 kPa (58 psi) to one end of the 177-7860 Hose .

16. Install one 8T-0853 Pressure Gauge with range 0 to 400 kPa (58 psi) to one end of the 177-7860 Hose .

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Illustration 6	g00698838

17. Install a 3J-7354 O-Ring Seal on a 5P-2937 O-Ring Adapter. Apply 5P-3413 Pipe Sealant to a 6V-3966 Fitting. Install the 6V-3966 Fitting into the 5P-2937 O-Ring Adapter. Use a suitable container under the plug (4) to collect spilled fluid. Remove the case vent port (4) from the piston pump (hydrostatic) on the first section of the piston pump (hydrostatic). Install the adapter into the case vent port (4) .

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Illustration 7	g00698843

18. Install the hose to the pressure tap (5) for the first section of the piston pump (hydrostatic) case. Install the remaining hose to the pressure tap (5) on the second section of the piston pump (hydrostatic) case.

19. Install one 6V-3989 Unvalved Nipple to 8T-0854 Pressure Gauge.

20. Install one 8T-0854 Pressure Gauge with range 0 to 1000 kPa (145 psi) to one end of the 177-7860 Hose .

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Illustration 8	g00698853
Pressure tap for the oil cooler (6)

21. Install the other end of the hose to the pressure tap (6) for the hydraulic oil cooler. The pressure tap (6) is located on the 142-8679 Return Manifold. The return manifold is located on the right side of the floor.

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Illustration 9	g00592868

22. Install a 6V-3121 Multitach, or install a 9U-7400 Multitach in order to measure engine rpm. Read the rpm from the reflective tape that is on the pulley for the engine crankcase.

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Illustration 10	g00592874

23. Install a 6V-3121 multitach group, or install a 9U-7400 multitach group in order to measure fan rpm. Read the rpm from the reflective tape that is on the fan blade.

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Illustration 11	g00561416
Route the lines in order to avoid pinching.

24. In order to test the machine, the ROPS structure needs to be lowered. Route the test hoses so that the ROPS structure does not rest on any of the hoses.

25. Start the engine and run the engine at low idle.

    If the engine rpm for the LOW idle is not correct, adjust the engine rpm. For the correct adjustment procedure, refer to Systems Operation and Testing and Adjusting For 3034 Engine For Caterpillar Built Machines, SENR5012.

26. Record the charge pressure, the speed sensing pressure, the pressures for the two piston pump (hydrostatic) case drains, the engine RPM and the fan RPM.

27. Increase the engine speed to high idle.

    If the engine speed for high idle is incorrect, perform the following checks.

    • If the engine speed is low, check for a parasitic load.

    • For the correct adjustment procedure, refer to Systems Operations and Testing and Adjusting For 3034 Engine For Caterpillar Built Machines, SENR5012.

28. Record the charge pressure, the speed sensing pressure, the pressures for the two piston pump (hydrostatic) case drains, the engine RPM and the fan RPM

Table 2

Test A For The 228 Skid Steer Loader And For The 248 Skid Steer Loader
Test	Low Idle		High Idle
	Spec	Actual	Spec	Actual
Engine Speed for the 228	1000 ± 50 rpm		2820 ± 50
Engine Speed for the 248	1000 ± 50 rpm		2900 ± 50 rpm
Charge Pressure	2900 ± 100 kPa (420.0 ± 15.0 psi)		3300 ± 200 kPa (478.6 ± 29.0 psi)
Speed Sensing Pressure for the 228	1100 ± 100 kPa (160.0 ± 15.0 psi)		2200 ± 100 kPa (319.0 ± 15.0 psi)
Speed Sensing Pressure for the 248	1000 ± 100 kPa (145.0 ± 15.0 psi)		2500 ± 100 kPa (363.0 ± 15.0 psi)
Pressure for the Pump Case	100 ± 50 kPa (15.0 ± 7.0 psi)		200 ± 100 kPa (30.0 ± 15.0 psi)
Pressure for the Cooler	100 ± 40 kPa (14.0 ± 6.0 psi)		170 ± 40 kPa (25.0 ± 6.0 psi)
Fan Speed for the 228	1225 ± 25 rpm		2750 ± 50 rpm
Fan Speed for the 248	1225 ± 25 rpm		2650 ± 50 rpm

If the charge pressure is too low or too high at high idle, perform the following checks.

• Check the gear pump.

• Replace the charge relief valve and recheck the pressure.

• There may be a restriction in the tube assembly between the two sections of the piston pump (hydrostatic).

• The possibility exists of a large internal leak.

• The fan motor may have failed.

If the charge pressure is too low at low idle, perform the following checks.

• The possibility exists of a large internal leak.

If the pressure of the piston pump (hydrostatic) case is high perform the following checks.

• Check for a restriction of the lines.

• Check the oil temperature. Make sure that the operating temperature of the oil is correct. Check the viscosity of the oil.

• There may be an internal leak.

• The possibility exists of a worn piston pump (hydrostatic).

If the pressure for the piston pump (hydrostatic) case is low, perform the following checks.

• The lip seal of the piston pump (hydrostatic) is blown. Check for the transferring of oil.

If the speed sensing pressure is low at low idle, perform the following adjustment.

Illustration 12	g00698887

Remove cap (7) from the speed sensing valve.

Illustration 13	g00698866
Adjustment to the speed sensing valve

• Turn the adjustment screw (8) on the speed sensing valve counterclockwise.

If the speed sensing pressure is high at low idle, perform the following adjustment.

• Turn the adjustment screw (8) on the speed sensing valve clockwise.

If the speed sensing pressure is low at high idle, perform the following adjustments.

• Turn the adjustment screw (8) on the speed sensing valve counterclockwise.

Note: If any adjustments have been made to the speed sensing valve, then repeat the test until the values are within specifications.

Note: Do not disconnect the lines or the gauges. The gauges will be used in order to check the pressures for the tests that follow. Leave the 6V-3121 Multitach or the 9U-7400 Multitach connected in order to measure the engine rpm for the tests that follow.

Test B

Start To Move Test

Perform the start to move test procedure for the piston pump (hydrostatic) in order to make sure that the piston pump (hydrostatic) fully destrokes. If the pump is not destroked the machine could move in the NEUTRAL position. If the pump is not fully destroked the wheels on one side of the machine could start to move before the wheels on the other side of the machine start to move.

Note: IF THE LEFT WHEELS AND THE RIGHT WHEELS START TO MOVE AT THE SAME TIME, THIS TEST IS NOT REQUIRED.

Note: Before performing this test, make sure that the drive chains are adjusted correctly.

Illustration 14	g00698985

Note: Before starting this procedure, clean the four tubes on the right end of the bank valve. To prevent contamination from entering the bank valve, clean the bank valve. Clean both ends of all four tubes.

1. Remove the hose clamp that holds the hydraulic drain line in position. Move the hose out of your way.

2. Place several 4C-8765 Absorbent Pads under the bank valve. Loosen nut (5) on tube (1) .

3. Place several 4C-8765 Absorbent Pads under nut (6). Loosen nut (6) on tube (1) .

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Illustration 15	g00699197

4. Install one 6V-9831 Cap (7) on the bank valve.

5. Install one 6V-9832 Cap (8) on the tee.

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Illustration 16	g00699211

6. Install one 7J-9108 O-Ring Seal into a 6V-9510 Face Seal Plug .

7. Install the 6V-9510 Face Seal Plug (9) into nut (5) on tube (1) .

8. Install one 6V-9746 O-Ring Seal into a 6V-9511 Face Seal Plug .

9. Install the 6V-9511 Face Seal Plug (10) into nut (6) on tube (1) .

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Illustration 17	g00699221

11. Place several 4C-8765 Absorbent Pads under the bank valve. Loosen nut (11) on tube (2) .

12. Place several 4C-8765 Absorbent Pads under nut (12). Loosen nut (12) on tube (2) .

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Illustration 18	g00699236

13. Install one 6V-9831 Cap (13) on the bank valve .

14. Install one 6V-9832 Cap (14) on the tee.

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Illustration 19	g00699243

15. Install one 7J-9108 O-Ring Seal into a 6V-9510 Face Seal Plug .

16. Install the 6V-9510 Face Seal Plug (15) into nut (11) on tube (2) .

17. Install one 6V-9746 O-Ring Seal into a 6V-9511 Face Seal Plug .

18. Install the 6V-9511 Face Seal Plug (16) into nut (12) on tube (2) .

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Illustration 20	g00699265

19. Place several 4C-8765 Absorbent Pads under the valve. Loosen nut (17) on tube (3) .

20. Place several 4C-8765 Absorbent Pads under nut (18). Loosen nut (18) on tube (3) .

21. Install one 6V-9831 Cap on the bank valve.

22. Install one 6V-9832 Cap on the tee.

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Illustration 21	g00699275

23. Install one 7J-9108 O-Ring Seal into a 6V-9510 Face Seal Plug .

24. Install the 6V-9510 Face Seal Plug (19) into nut (17) on tube (3) .

25. Install one 6V-9746 O-Ring Seal into a 6V-9511 Face Seal Plug .

26. Install the 6V-9511 Face Seal Plug (20) into nut (18) on tube (3) .

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Illustration 22	g00699292

27. Place several 4C-8765 Absorbent Pads under the valve. Loosen nut (21) on tube (4) .

28. Place several 4C-8765 Absorbent Pads under nut (22). Loosen nut (22) on tube (4) .

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Illustration 23	g00699315

29. Install one 6V-9831 Cap (23) on the bank valve.

30. Install one 6V-9832 Cap (24) on the tee.

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Illustration 24	g00699321

31. Install one 7J-9108 O-Ring Seal into a 6V-9510 Face Seal Plug .

32. Install the 6V-9510 Face Seal Plug (25) into nut (17) on tube (4) .

33. Install one 6V-9746 O-Ring Seal into a 6V-9511 Face Seal Plug .

34. Install the 6V-9511 Face Seal Plug (26) into nut (18) on tube (4) .

35. Install one 6V-3989 Unvalved Nipple to 8T-0857 Pressure Gauge. Repeat this step twice.

36. Connect two 8T-0857 Pressure Gauges with a range of 0 to 10000 kPa (0 to 1450 psi) to the two 177-7860 Hose Assemblies .

Note: Perform the test on the front section of the pump first. The front section of the pump powers the piston motor (hydrostatic) on the left side of the machine.

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Illustration 25	g00704639
(27) Neutral Adjusting Bolt (A) The MA Ports (B) The MB Ports (C) Front Pump Section (D) Rear Pump Section

37. Install the end of one hose assembly to the MA port on the rear section of the pump. Install the end of one hose assembly to the MB port on the rear section of the pump.

38. In this test, the wheels will begin to spin. Make sure that all hoses are out of the way of the rotating wheels.

39. Place the two gauges in an easily visible position.

40. Lower the cab. Start the engine. Run the engine at LOW idle. Raise the cab.

    Hold the neutral adjusting bolt (27) .

    Loosen the locknut that is around the neutral adjusting bolt with a socket. Do not use an impact socket.

    Turn the neutral adjusting bolt (27) clockwise. Mark the location of the neutral adjusting bolt when the MA pressure increases.

    Turn the neutral adjusting bolt (27) counterclockwise. Mark the location of the neutral adjusting bolt when the MB pressure increases.

    Turn the neutral adjusting bolt (27) halfway between the two marks.

    Hold the neutral adjusting bolt (27) in position. Tighten the locknut to 44 ± 2 N·m (32 ± 1 lb ft).

41. Perform this test on the rear pump section. The rear section of the pump powers the piston motor (hydrostatic) on the right side of the machine.

1. Check that the left wheels and the right wheels start to move at the same time.

2. If the wheels do not start to move at the same time, then repeat this test.

3. Install the four tubes on the bank valve. Install tube (4) first. Install the tubes in reverse order.

4. If the wheels start to move at the same time, then remove the hoses from the MA and MB pressure taps.

Test C

Stall Test

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Sudden movement of the machine or release of oil under pressure can cause injury to persons on or near the machine. To prevent possible injury, perform the procedure that follows before testing and adjusting the power train.

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Personal injury can result from hydraulic oil pressure and hot oil. Hydraulic oil pressure can remain in the hydraulic system after the engine has been stopped. Serious injury can be caused if this pressure is not released before any service is done on the hydraulic system. Make sure all of the attachments have been lowered, oil is cool before removing any components or lines. Remove the oil filler cap only when the engine is stopped, and the filler cap is cool enough to touch with your bare hand.

The test C is for the stall test for the hydrostatic system. Perform the test in order to determine the system that is causing a problem. The test stalls the hydrostatic system. The test can be used in order to identify low power problems with the engine. The test is also used to identify the crossover relief valves that may be malfunctioning.

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Illustration 26	g00699520

1. Park the machine against a stationary object. The brakes should be engaged. To engage the brake, disconnect the brake solenoid electrical connection (1) on the interlock manifold.

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Illustration 27	g00704639
(27) Neutral Adjusting Bolt (A) The MA Ports (B) The MB Ports (C) Front Pump Section (D) Rear Pump Section

2. The 6V-3121 Multitach or the 9U-7400 Multitach should still be installed on the machine. If the units are not installed, reinstall the units.

3. Remove the two 8T-0857 Pressure Gauges from the hose assemblies. Attach one 8T-0861 Pressure Gauge to each hose assembly.

4. Start the engine and run the engine at low idle.

5. Slowly increase the engine speed to high idle.

6. Push in the FORWARD direction on the joystick control (hydrostatic) until the engine stalls.

7. Record the engine rpm and record the MA pressures for the drive loops.

Table 3

Test C Stall Test
Test	Spec	Actual
Engine Stall Speed	2200 ± 500 rpm
MA Pressure	38200 ± 2000 kPa (5540 ± 290 psi)

If the engine lug is high, perform the following check.

• The piston pump (hydrostatic) may have an internal leak, or the piston motor (hydrostatic) may have an internal leak.

• The engine power may be low. Refer to System Operation and Testing and Adjusting, SENR5012 for the correct adjustment procedures.

• The speed sensing valve may be set too high.

Perform the following check if the engine lug is low for the stall of the hydrostatic system.

• The speed sensing valve may be set too low.

If the MA pressure is low and the engine lug is high, perform the following checks.

• The crossover relief valve is set incorrectly. Switch the two crossover relief valves. If the problem is not corrected then replace the piston pump (hydrostatic).

Test D

Double Stall Test

The test will determine if engine performance is within specifications.

1. The brake solenoid should still be disconnected and the machine should still be blocked.

2. The 6V-3121 Multitach or the 9U-7400 Multitach should still be installed on the machine. If the units are not installed, reinstall the units.

3. Start the engine.

4. Increase the engine speed to high idle.

5. Push the joystick control (hydrostatic) in the FORWARD direction. At the same time push FORWARD on the joystick control (work tool). Do not stall the machine for more than 15 seconds.

6. Record the MA pressures, and the engine rpm.

Table 4

Test D Double Stall Test
Test	Spec	Actual
MA Pressure	38200 ± 2000 kPa (5540 ± 290 psi)
Double Stall Speed	2000 ± 500 rpm

If the engine rpm is not to the correct specification, perform the following checks.

• The engine power is low. For the correct adjustment procedure, refer to Systems Operation and Testing and Adjusting, SENR5012-00.

• Check for a parasitic load.

• Check the speed sensing valve. Adjust the speed sensing valve if the setting is not set to specifications.

• Check the main relief valve. Adjust the main relief valve if the setting is not set to specifications.

Perform the following check if the engine lug is within the specifications for the hydrostatic system stall, but the engine lug is low for the hydraulic system stall.

• The main relief valve may be set too low.

• There may be an internal leak in the hydraulic system.

Perform the following check if the engine lug is within the specifications for the hydrostatic system stall, but the engine lug is high for the hydraulic system stall.

• The engine may have low power.

• The main relief valve may be set too high.

Perform the following check if the engine lug is within the specifications for the hydraulic system stall, but the engine lug is high for the hydrostatic system stall.

• The piston motor (hydrostatic) may have an internal leak.

• The piston pump (hydrostatic) may have an internal leak, or the piston motor (hydrostatic) may have an internal leak.

• The crossover relief valve may be set too low or the crossover relief valve may be damaged.

• The speed sensing valve may be set too high.

Test E

Maximum Runout

The test is used to determine if the engine and the machine speeds are correct for the maximum travel speed.

Note: Connect the brake solenoid (1) in illustration 26.

1. The hose assemblies and gauges for charge pressure and for speed sensing pressure should still be in place. If the units are not in place reinstall the units.

2. The hose assemblies for the MA ports should be in place from the previous test. If the hose assemblies are not installed, reinstall the hose assemblies.

3. The 6V-3121 Multitach or the 9U-7400 Multitach should still be installed on the machine. If the units are not installed, reinstall the units.

4. Use wood blocks to elevate the machine. The wheels may not touch the ground.

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Illustration 28	g00704657
(1) Reflective tape

5. One wheel on each side of the machine must be checked for proper speed. Apply four pieces of reflective tape (1) to each wheel at 90 degree intervals. Use a 1U-6602 Phototach to record the RPM of the wheels.

6. Start the machine and run the machine at high idle. Push in the FORWARD direction on the joystick control (hydrostatic). Record the RPM of a wheel on each side of the machine and divide that number by four.

7. Record the MA pressures, the speed sensing pressures, the charge pressure and the wheel RPM.
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   Table 5

   Test F For The 228 Skid Steer Loader And 248 Skid Steer Loader The Maximum Speed Test For The Displacement Control For The Pumps And For The Motors In The Forward Direction
   Test	Spec	Actual
   Speed Sensing Pressure for the 228 Skid Steer Loader	2200 ± 100 kPa (319.0 ± 15.0 psi)
   Speed Sensing Pressure for the 248 Skid Steer Loader	2500 ± 100 kPa (363.0 ± 15.0 psi)
   Charge Pressure	3200 ± 200 kPa (464.0 ± 29.0 psi)
   MAPressure	6000 ± 500 kPa (800 ± 85 psi)
   Wheel RPM	80 ± 8 rpm The wheel speeds must be within 2 RPM of each other.

Perform the following check if the pump signal pressure is not to the correct specification.

• The speed sensing valve may be misadjusted.

Perform the following check if the MApressure and the MB pressure is high for the FORWARD and the REVERSE directions.

• The axle may have a problem.

• The brake may not be released.

• The chain drive may be out of adjustment.

Test F

Brake Test

This test will determine if the brakes are functioning correctly. This test will check the interlock manifold and the piston motor (hydrostatic).

1. Raise the cab. Refer to Operation and Maintenance Manual, SEBU7255, "Cab Support Operation" for the 248 Skid Steer Loader. Refer to Operation and Maintenance Manual, SEBU7205, "Cab Support Operation" for the 228 Skid Steer Loader.

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Illustration 29	g00699520

2. Disconnect the brake solenoid electrical connection (1) .

3. Install one 3J-1907 O-Ring Seal on a 6V-3965 Fitting. Install the fitting on a 8T-8902 Tee .

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Illustration 30	g00699624

4. Install the 8T-8902 Tee (2) in the hydraulic line that runs from the interlocking manifold valve and mounting to the piston motors (hydrostatic). To install the tee, move the hose to the piston pump (hydrostatic).

5. Install a 8T-0855 Pressure Gauge to the end of a 177-7860 Hose .

6. Install the other end of the 177-7860 Hose to the diagnostic tee.

7. Lower the cab.

8. Start the machine. The pressure gauge should read 0. If the gauge does not read 0, inspect the brake solenoid and the voltage for the brake solenoid.

9. Stop the machine. Raise the cab and reconnect the brake solenoid.

10. Lower the cab and start the machine.

11. Disengage the parking brake by pressing the hydraulic enable switch. The pressure on the gauge should be 2900 ± 100 kPa (420 ± 14 psi).

12. If the pressure is not correct inspect the brake solenoid, the voltage for the brake solenoid and the brake seal inside the piston motor.

Test G

Drift Test and Adjustment for the Maximum Displacement Stops

The test procedure checks machine drift. The new adjustment procedures should be done when the machine drifts more than 3 m (10 ft) to either side of a straight line of travel over a distance of 30.5 m (100 ft).

1. Move the machine to a testing location that is flat, level, and 30.5 m (100 ft) long. Allow enough space on each side of the center line for any machine drift that could exceed 3 m (10 ft).

2. Inflate all four tires to the same air pressure.

3. Start the test outside the test area. The machine must enter the testing location in straight line travel and travelling at full speed. The engine must be set to high idle and the joystick control must be positioned fully forward.

4. Measure the amount of drift and record the direction of drift.

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Illustration 31	g00704727
Turn the adjustment screw (1) clockwise when the machine drifts to the left. Turn the rear adjustment screw (2) clockwise when the machine drifts to the right.

5. If the machine drifts over 3 m (10 ft) to the left, you must turn the adjustment screw (1) by 1/8 of a turn clockwise. Refer to the illustration for the location of the displacement adjustment screw.

   If the machine drifts over 3 m (10 ft) to the right, you must turn the adjustment screw (2) by 1/8 of a turn clockwise. Refer to the illustration for the location of the displacement adjustment screw.

   Note: After every adjustment to an adjustment screw, repeat the drift test until the machine drift is acceptable.

6. After you finish adjusting an adjustment screw, tighten the locknut to a torque of 22 N·m (16 lb ft). Cover the maximum displacement adjustment screws with 6E-5060 Caps .