SD-30-4265 ® C-300N/C-500N HYDRAULIC POWER STEERING GEAR OUTPUT SHAFT C-300N NAME PLATE OIL RETURN OIL SUPPLY OUTPUT SHAFT ADJUSTING SCREW NAMEPLATE C-500N VALVE BODY OIL RETURN OIL SUPPLY INPUT SHAFT SIDE COVER ADJUSTING SCREW STEERING LIMITING STEM PLUG VALVE BODY OUTPUT SHAFT HOUSING DESCRIPTION The Compact 300N and 500N (C-300N/C-500N), Hydraulic Power Steering Gears are designed for medium and heavy duty vehicles with front axle weight ratings of 6,000 to 9,000 lbs for the C-300N and up
SD-30-4265 TABLE OF CONTENTS DESCRIPTION .............................................................. 1 OPERATION .................................................................. 1 General ........................................................................ 1 Mechanical .................................................................. 3 Hydraulic ..................................................................... 4 Rotary Control Valve ....................................................
PISTON OVER OUTPUT SHAFT MOUNTING (LEFT HAND THREAD SPINDLE) SPINDLE ASSEMBLY INPUT SHAFT PISTON UNDER OUTPUT SHAFT MOUNTING (RIGHT HAND THREAD SPINDLE) STEERING WHEEL OUTPUT SHAFT SPINDLE ASSEMBLY INPUT SHAFT STEERING WHEEL PISTON VEHICLE RIGHT TURN PITMAN ARM PITMAN ARM PISTON OUTPUT SHAFT VEHICLE LEFT TURN FIGURE 1 - MECHANICAL OPERATION OPERATION GENERAL Both steering gears are composed of mechanical and hydraulic power assist components. Actual steering is accomplished mechanically.
TIE ROD ARM TIE ROD DRAG LINK PITMAN ARM STEERING ARM SPINDLE ASSEMBLY PISTON UNDER OUTPUT SHAFT PISTON OVER OUTPUT SHAFT FIGURE 3 - POWER STEERING GEAR MOUNTING CONFIGURATION When the steering gear is mounted on the vehicle in a position similar to the piston under output shaft illustration in figure 1, the piston and spindle used will have a right hand thread. A left hand thread is required when the steering gear is mounted in a position similar to the piston over output shaft illustration.
OUTPUT SHAFT SIDE VIEW RACK AND SECTOR GEAR PISTON TORSION BAR BALL SCREW ROTARY VALVE SPINDLE ASSEMBLY INPUT SHAFT HOUSING STEERING LIMITING STEM POPPET SEAT END VIEW STEERING LIMITING STEM POPPET VALVE SEAL AND BACKUP RING VALVE BODY VALVE NUT RECIRCULATING BALLS NAMEPLATE STEERING LIMITING STEM STEM PLUG C-500N DETAIL ROLLER BEARINGS DUST DUST BOOT SEAL ADJUSTING SCREW SPACER ADJUSTING SCREW OUTPUT RACK AND SHAFT SECTOR GEAR RECIRCULATING BALLS PISTON HOUSING POPPET VALVE SEAT ADJU
BALL SCREW (OUTER VALVE ELEMENT) OIL OUT (RIGHT TURN) OIL IN TORSION BAR PIN OIL RETURN HOLES (HIDDEN FROM VIEW) OIL RETURN HOLE INPUT SHAFT (INNER OIL OUT LEFT (FROM VALVE ELEMENT) ROTARY PISTON TURN VALVE CAVITY) GROOVES STEERING (6) STOP OIL RETURN SPLINES HOLES (TO PIN HOLE TORSION BAR PUMP RES.
EXTREME LEFT TURN POSITION POPPET VALVE OPEN OUTPUT SHAFT RETURN SIDE OF PISTON PISTON HOUSING EXTREME RIGHT TURN POSITION POPPET VALVE OPEN BALL INPUT SCREW SHAFT OUTPUT SHAFT PISTON POPPET VALVE INPUT SHAFT SPINDLE ASSEMBLY LIMITING STEM POPPET VALVE PRESSURIZED SIDE OF PISTON DURING PISTON SPRING LEFT TURN POPPET SEAT ADJUSTABLE STEM O-RING FIGURE 7 - STEERING LIMITING POPPET VALVE OPERATION upon the piston surface eliminates much of the pistons resistance to movement.
OIL RETURN CHANNEL POWER INPUT STEERING GEAR SHAFT HOUSING BENDIX ASSEMBLY PART NUMBER VALVE BODY SERIAL NUMBER MONTH ASSEMBLED (A = JAN., ETC. VEHICLE MFGR PART NUMBER SPRING BYPASS VALVE OIL RETURN OIL SUPPLY PORT PORT FIGURE 9 - BYPASS VALVE OPERATION BYPASS VALVE OPERATION The optional bypass valve is located adjacent to the pressure relief valve in the valve body.
EXTERIOR BOOTS AND DUST SEALS REMOVING THE POWER STEERING GEAR Inspect the integrity of the output and input shaft boot and dust seal. These components prevent contamination from entering the housing around the shaft. If deterioration is noted, these components should be replaced. The cavities between the boots and seals should be filled with special high temperature grease. 1. Mark or identify the inlet and return lines at the valve body ports.
42 44 7 C-500N DETAIL OF VALVE BODY AND STEERING LIMITING STEM 41 43 21 19 A1 45 46 20 48 47 17 9 51 52 23 22 20 38 13 9 18 16 18 53 17 39 54 21 10 40 19 12 11 14 15 9 7 35 37 29 24 28 36 26 4 1 5 6 9 35 9 28 34 ALTERNATE BALL RETURN TUBE STYLE FOR C-300/N/C-500N 29 30 27 31 32 49 10 2 50 8 3 B2 25 26 33 FIGURE 7 - C-300N / C-500N POWER STEERING GEAR POWER STEERING PARTS LIST 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21.
5. Remove the steering gear from the vehicle. SPECIAL TOOLS Two special tools are required to disassemble/assemble the C- 300N and C-500N. The tools listed and illustrated here are useful but not all required. All special tools may be obtained from authorized Bendix part outlets. DISASSEMBLY GENERAL A high level of cleanliness should be observed at all times when working on the power steering gear. Clean the exterior of all parts prior to disassembly.
2. Scribe a line or otherwise mark the relationship of the valve body to the housing. Using a 19mm wrench remove the four bolts (40) that secure the valve body (7) to the housing (22). Figure 14 3. Separate the valve body(7) from the housing (22) by rotating the output shaft (25) using the pitman arm. It may be necessary to hold or rotate the input shaft (3) during this operation. Continue to separate the valve body from the housing until both O-rings (12) on the valve body can be seen. Figure 15. 4.
FIGURE 18 - SIDE COVER & ROLLER BEARINGS 5. Loosen and remove the lock nut (32) from adjusting screw (33) on the side cover(31) using a 19mm wrench. 6. Scribe a line or otherwise mark the relationship of the side cover (31) to housing (22). Using a 19mm wrench, remove the four bolts (49) that secure the side cover to the housing. Figure 17 7. Separate the side cover from the housing by turning the adjusting screw (33) clockwise with a 7mm socket.
PISTON REMOVAL & DISASSEMBLY 9. While preventing rotation of the input shaft end of the spindle assembly (3), pull the valve body (7) and piston (23) out of the housing (22). Figure 20 10. Remove the retaining ring (36), ball tube cover (24), the ball tube (35), and 7 of the 26 balls (9) from the piston(23). Remove the sealing ring(37) from the piston. Note: Bendix holding fixture 297678 which is pictured is a convenience but not a necessity for disassembly. Figures 21 to 24 11.
SEALING WASHER ITEM 18 VALVE SEAT BALL ITEM 17 ITEM 9 SEALING WASHER ITEM 18 SPRING ITEM 16 BALL ITEM 9 VALVE SEAT ITEM 17 PISTON ITEM 23 FIGURE 27 - REMOVING/INSTALLING STEERING LIMITING COMPONENTS FIGURE 25 - REMOVING/INSTALLING SPINDLE Separate the valve body and spindle from the piston. Check the inside of the piston for any stray balls (9) that may not have been removed in the operation above. A total of 26 balls, 7 from the ball tube and 19 from the piston, should be accounted for. Figure 25 12.
FIGURE 29 - REMOVING INSTALLING SIDE COVER SEAL & O-RING FIGURE 31 - REMOVING/INSTALLING HOUSING OUTPUT SHAFT SEAL (seal and nylon split ring) may not be used in all steering gears. A one piece seal is sometimes used instead. CAUTION: Do not remove the outer race of the roller bearing from the housing. VALVE BODY & SPINDLE DISASSEMBLY 19. If the steering gear is not equipped with the steering limiting feature, this STEP MAY BE DISREGARDED.
externally without removal of the valve body (7) from the housing (22). See the inset in figure 4 and 11. Remove the steering limiting stem protective plug (21) from the valve body (7) and using a screw driver, remove the steering limiting stem (19) and O-ring (20) from the valve body (7). Separate and discard the O-ring (20) from the stem (19). 20. Remove the input shaft dust seal (4) from the valve nut (1). Figure 32 21.
23. Separate the outer race (8), ball cage (6) and 17 balls (9) from the spindle assembly (3). Figure 36 24. Do not remove the other half of the ball bearing outer race (8) in the valve body. OUTPUT SHAFT DISASSEMBLY 27. Remove the retaining ring (30), the adjuster screw spacer (34) and the adjuster screw (33) from the output shaft (25). Figure 39 25. Remove the retaining ring (50) and then the seal (5) from the valve nut (1). Figure 37 26.
PRESSURE RELIEF & BYPASS VALVE DISASSEMBLY 28. If the steering gear is equipped with a pressure relief valve, begin disassembly by removing the plug (42) and its sealing washer (44) from the valve body (7). Figure 40. 29. Remove the spring (43), spring seat (45), adjusting shims (41) and the valve piston (46). Figure 40. 30. Using a wide bladed screwdriver or tool 298077, remove the valve seat (48) and its sealing washer (47).
base grease. The spindle assembly can be used to assist in pushing the tool through the bore. Figure 42 & 38 6. Install the two O-rings (12) on the valve body (7). Figure 38 7. Install the ball cage (6) over the input shaft end of the spindle assembly (3). Using a general purpose lithium base grease to hold them in place, install the seventeen balls (9) in the ball cage. Figure 43 8.
FIGURE 44 - INSTALLING SPINDLE ASSEMBLY torque the valve nut to between 221 and 257 pound feet. Figure 34 Reset the safety point between the valve nut and valve body using a drift punch or similarly appropriate tool. Figure 33 11. If the steering gear was equipped with the steering limiting feature follow the appropriate stem installation procedure. C-300N POWER STEERING GEAR If it was necessary to remove the limiting stem from the valve body, install the stem (13) now.
PISTON ITEM 23 STRIP OF SHEET METAL OVERLAPPING ITSELF AND ON TOP OF GLIDE RING HOSE CLAMP FIGURE 46 - RESHAPING THE PISTON GLIDE RING (5) should be filled with the high temperature grease provided in the Bendix maintenance kits. PISTON REASSEMBLY 13. Install one of the two steering limiting valve seats (17)and its sealing washer (18), into the piston (23).
Before proceeding further, identify the type of ball return tube that is being installed. If the OLD STYLE ball return tube is in use, PROCEED TO STEP 19. If the NEW STYLE ball return tube is in use, PROCEED TO STEP 21. OLD STYLE BALL TUBE 19. Insert the valve body and spindle assembly (3) all the way into the piston (23) making certain that the stroke limiting stem (13) is not damaged and that it mates with the valve seat (17) in the piston (23).
SEAL ITEM 29 PRESSURE SEALING LIP FOR I.D. BACKUP RING ITEM 28 PRESSURE SIDE OF SEAL BACKUP RING INSTALLED IN NON-PRESSURE SIDE OF SEAL NON-PRESSURE SIDE OF SEAL PRESSURE SEALING LIP FOR O.D. FIGURE 50 - DETAIL OF SEAL & BACKUP RING ASSY. FIGURE 52 - INSTALLING STEERING LIMITING STEM FIGURE 53 - INSTALLING OUTPUT SHAFT ROLLERS IN HOUSING spindle should rotate freely and will begin to thread into or out of the piston depending upon the direction of spindle rotation.
making certain the slot in the underside of the cover mates with the recirculating tube in the piston. Install the retaining ring (36) in the piston to secure the tube cover making certain it is completely seated in its groove. After assembly, check for smooth rotation of the spindle assembly in both directions. Figures 21, 22, 24 HOUSING REASSEMBLY 23. Reaching through the side cover opening of the housing (22), install the seal (29) with its pressure side toward the INTERIOR of the housing.
travels through the mid point of its travel and should disappear as the piston moves past the midpoint. To obtain the adjustment stated above, make certain the adjusting screw (33) is turned counterclockwise as far as it will go. Rotate the input shaft as far as possible in both directions. Count the total revolutions in either direction and at the same time measure the average torque to rotate the shaft.
1. Adjust the axle stops using the vehicle manufacturers specifications. 2. Install a pressure gauge or gauge and flow meter combination in the pressure (supply) line between the power steering pump and steering gear. Figure 56. Note: If a shut off valve is part of the gauge or gauge/flow meter, make certain the valve is open. Caution: During the procedure that follows, use extreme care not to operate the power steering pump at its relief valve pressure for more than a few seconds at a time.
ON-VEHICLE POWER STEERING TESTS PRELIMINARY 1. Install a flow meter, pressure gauge (3,000 p.s.i. minimum) and a shut off valve in the pressure line between the power steering pump and gears illustrated in the figure. MAKE CERTAIN THE SHUTOFF VALVE IS OPEN. 2. Install a thermometer capable of reading 300°F in the power steering pump reservoir. 3. Turn the vehicles front wheels to the straight ahead position, engage the parking brake and place the transmission gear selector in neutral. 4.
4. Repeat Step 3 - turning the steering wheel in the opposite direction. 5. With the engine off remove the pressure relief test plug assembly (106773). Reinstall the spring (43). Install a new (unused) sealing washer (44) on the pressure relief valve plug (42) then install the adjusting shims (41) in the plug. Install the plug (42) in the valve body(7) and torque to 66-73 pound feet. Step 5 must be completed before placing the vehicle back in service.
SYMPTOM 1. Power steering does not operate or manual steering effort is excessive. TROUBLESHOOTING CHART CAUSE 1. Low oil level. 1. Check oil level. 2. Air in system. 2. Check that there are no leaks, bleed and top up with oil. 3. Check pump performance to specification. 4. Remove lines and clean. 3. The pressure pump does not supply an adequate flow or pressure. 4. Obstruction in the oil reservoir outlet or inlet. 5. Internal leakage in power steering gear piston. 6.
SYMPTOM 7. Power steering stiff when turning steering wheel quickly. TROUBLESHOOTING CHART CAUSE 1. Restricted hose. 2. Incorrect hose size. 3. Faulty operation of hydraulic pump. 4. Internal leakage in power steering gear. 8. Power steering does not return correctly. 9. Power steering operates but with noise, turbulence or vibration 1. Low tire pressure. 2. Front axle assembly deformed as a result of accident or breakdown in the rotary valve unit. 3. Bind in intermediate shafts. 4.
