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31

TROUBLESHOOTING CHART

SYMPTOM

CAUSE

REMEDY

7. Power steering stiff

1. Restricted hose.

1. Replace incorrect or

when turning steering

unserviceable hoses.

wheel quickly.

2. Incorrect hose size.

2. Replace incorrect or

unserviceable hoses.

3. Faulty operation of hydraulic pump.

3. Check pump to performance

specifications. Overhaul by

authorized workshop.

4. Internal leakage in power steering

4. Verify by test; repair if necessary.

gear.

8. Power steering does not

1. Low tire pressure.

1. Inflate tires to correct pressure.

return correctly.

2. Front axle assembly deformed as a

2. Lubricate front axle assembly.

result of accident or breakdown in

Check for damaged or worn parts.

the rotary valve unit.

3. Bind in intermediate shafts.

3. Determine cause and correct.

4. Lower steering gear parts deformed

4. Replace the piston and spindle

as a result of accident or breakdown

assembly.

in the rotary valve unit.

9. Power steering operates

1. Reservoir oil level low.

1. Fill up to level.

but with noise,

2. Piping contacting part of the body-

2. Space pipe from bodywork, if not

turbulence or vibration

work, causing vibrations (particularly

possible, insulate with a rubber

the pressure feed line).

spacer.

3. Unsuitable oil.

3. Drain oil and fill up with

recommended grade.

4. Oil reservoir filter blocked.

4. Replace filter.

5. Power steering pump.

5. Repair or replace.

BW2600   © 2002 Bendix Commercial Vehicle Systems LLC All rights reserved.  3/2002 Printed in U.S.A.

Содержание C-300N HYDRAULIC POWER STEERING

Страница 1: ... that the C 500N is proportionately larger than the C 300N The vehicle s steering column is coupled to the gear at the input shaft which transmits steering effort through a recirculating ball screw spindle assembly and piston The piston is an integral part of the power assist and also acts as a steering damper The direction and degree of power assist is controlled by a rotary hydraulic valve which...

Страница 2: ...Dust Seals 9 CAUTION NOTE 9 REMOVAL 9 SPECIAL TOOLS 9 DISASSEMBLY 11 General 11 Output Shaft Removal 11 Piston 13 Main Housing Side Cover 15 Valve Body Spindle 16 Output Shaft 18 Pressure Relief Bypass Valve 18 Spindle 18 CLEANING INSPECTION 19 REASSEMBLY 19 General 19 Valve Body Spindle 19 Piston 21 Housing 24 Output Shaft Side Cover 25 ADJUSTMENT 26 Piston to Output Shaft Gear Backlash 26 Stroke...

Страница 3: ...ly to reduce the mechanical effort required to turn the vehicle s steering wheel Loss of hydraulic power will in no way prevent the vehicle from being maneuvered mechanically however greater effort will be required to turn the steering wheel MECHANICALOPERATION The turning effort exerted by the driver on the steering wheel is transmitted to the input shaft which is part of the spindle assembly The...

Страница 4: ...essen the manual steering effort required in the event hydraulic pressure is lost The bypass valve permits fluid to circulate within the steering gear rather than being forced to and from the power steering pump and reservoir Figure 9 The spindle assembly rotates on a ball bearing in the bore of the valve body The spindle is composed of three major parts the input shaft torsion bar and ball screw ...

Страница 5: ...POPPET SEAT POPPET VALVE RECIRCULATING BALLS STEERING LIMITING STEM VALVE BODY VALVENUT SIDE VIEW FIGURE 4 POWER STEERING GEAR ADJUSTING SCREW ADJUSTING SCREW LOCK NUT SIDECOVER BALL TUBE BALL TUBE COVER POPPETVALVE SEAT HOUSING PISTON RECIRCULATING BALLS RACKAND SECTOR GEAR OUTPUT SHAFT DUST SEAL DUST BOOT SEALAND BACKUPRING ROLLER BEARINGS NAMEPLATE ADJUSTING SCREWSPACER END VIEW ...

Страница 6: ... OUTERVALVE ELEMENT TO PUMP RES OIL IN OIL OUT RIGHT TURN OIL OUT LEFT TURN OIL IN OIL RETURNING FROM RIGHT TURN SIDE OF POWER PISTON OIL RETURNING FROM LEFT TURN SIDE OF POWER PISTON ROTARY CONTROL VALVE OPERATION The rotary control valve is an open center type which allows a continuous flow of oil through the longitudinal grooves in the input shaft and bore of the ball screw when held in the neu...

Страница 7: ... as pressurized oil passes around the poppet valve to the other side of the piston and to the return line Continued movement of the piston will result in removal of increasing amounts of power assist and cause increased steering effort Steering limiting reduces the maximum power assist that can be transmitted to the axle steeringlinkagesandcomponents Figure7Whenthisfeature is incorporated in the C...

Страница 8: ... full lock to full lock until all the oil is drained out 3 Clean the outside of the reservoir Remove and replace the old filter element 4 Fill reservoir full of oil 5 Turn the engine over with the starter motor Must be done in a manner that the engine does not start Add oil as the level drops to avoid air being drawn into the system 6 When the oil level reaches the full mark on the dipstick start ...

Страница 9: ...lly charged components 6 Never connect or disconnect a hose or line containing pressure it may whip Never remove a component or plug unless you are certain all system pressure has been depleted 7 Never exceed recommended pressures and always wear safety glasses 8 Do not attempt to install remove disassemble or assemble a component until you have read and thoroughly understand the recommended proce...

Страница 10: ...n Ring 11 O Ring 12 O Ring 13 Steering Limiting Stem 14 Seal Ring 15 O Ring 16 Spring 17 Valve Seat 18 Sealing Washer 19 Steering Limiting Stem 20 O Ring 21 Plug 22 Housing 23 Piston 24 Tube Cover 25 Output Shaft 26 Rollers 27 O Ring 28 Backup Ring 29 Seal Backup Ring 30 Retaining Ring 31 Side Cover 32 Nut 33 Adjusting 34 Adjusting Screw Spacer 35 Ball Tube 36 Retaining Ring 37 O Ring 38 Dust Seal...

Страница 11: ... disassembly The following disassembly and assembly procedure is presented for reference purposes and presupposes that a major rebuild of the power steering gear is being undertaken Several replacement parts and maintenance kits are available which do not require full disassembly The instructions provided with these parts and kits should be followed in lieu of the instructions presented here After...

Страница 12: ...ecessary 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 Scribe a line or otherwise mark the relationship of the pitman arm to the output shaft 25 then remove the pitman arm then the dust boot 39 Figure 16 CAUTION Do not use heat or pound on the pitman arm or output shaft ...

Страница 13: ...ollers in the side cover bearing 26 will fall out loose These rollers MUST NOT BE INTERCHANGED with the rollers in the housing bearing which is identical Figure 17 18 CAUTION Do not attempt to remove the outer race of the roller bearing from the side cover 8 Install the pitman arm and use it to center the piston 23 and output shaft 25 gear teeth inside the side cover opening of the housing Remove ...

Страница 14: ...e 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 In order to remove the remaining 19 balls 9 from piston rot...

Страница 15: ...eering limiting valve feature disregard steps 13 15 Remove either of the steering limiting valve seats 17 and sealing washer 18 from the piston Either a Phillips or straight blade screwdriver will be required depending upon which of the two styles of body is in use Figure 27 Note Care must be taken during this operation since damage to the screwdriver slot will make removal difficult 14 Remove one...

Страница 16: ...e steering limiting feature this STEP MAY BE DISREGARDED Follow the appropriate procedure C 300N POWER STEERING GEARS In the C 300N power steering gear the steering limiting stem is threaded into a blind hole in the valve body and is accessible only after the valve body 7 has been removed from the housing 22 Check the condition and length of the limiting stem 13 in the valve body 7 The length of t...

Страница 17: ...d 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 With a drift punch unblock the safety point between the valve nut 1 and valve body 7 Using Spanner wrench 106234 loosen and remove the valve nut 1 from the valve body 7 Figures 33 ...

Страница 18: ...e ball bearing outer race 8 in the valve body 25 Remove the retaining ring 50 and then the seal 5 from the valve nut 1 Figure 37 26 Remove the two outside O rings 12 from the valve body then remove the three Teflon rings 10 and the corresponding three O rings 11 from the spindle bore Figure 38 OUTPUT SHAFT DISASSEMBLY 27 Remove the retaining ring 30 the adjuster screw spacer 34 and the adjuster sc...

Страница 19: ...valve body must be replaced Inspect the bearing surfaces of both the inputs 2 Gear teeth in the output shaft and piston may show signs of polishing and slight wear however pitting spalling and cracks should not be present 3 Output and input shaft splines 4 Check the ball rolling surfaces on the exterior of spindle and interior of piston for cracks pitting spalling and brinelling 5 Exterior of pist...

Страница 20: ...ose lithium base grease to hold them in place install the seventeen balls 9 in the ball cage Figure 43 8 Install the outer ball bearing race half 8 over the input shaft end of the spindle assembly 3 and insert the spindle assembly through Bendix tool 297676 Insert the spindle and tool into the valve body 3 until tool completely exits the other side and the seventeen balls 9 of the bearing assembly...

Страница 21: ...enance manual apply Loctite 222 or 262 to the threads and screw the limiting stem 13 into the valve body 7 until the correct stem height is obtained above the valve body surface IMPORTANT Use care in applying the Loctite compound to prevent this material from coming in contact with other surfaces of the valve body Figure 4 11 C 500N POWER STEERING GEAR Using lithium grease lubricate and install th...

Страница 22: ...AN OPEN FLAME to heat the glide ring A heat lamp or a similar device should be used 16 Install the heated glide ring 14 over the O ring 15 in the piston s groove 23 IMPORTANT The glide ring should be distorted as little as possible during installation Using an automotive piston ring compression tool or a smooth piece of sheet metal and an appropriately large screw type hose clamp reshape the glide...

Страница 23: ...nside the piston or coming out at the top and lodging in the housing 20 Install the remaining seven balls 9 in the recirculating tube halves 35 and use lithium base grease to retain them in the tube Seat the assembled tube halves 35 containing the seven balls in the recirculating tube holes in the piston 23 Lightly grease the sealing surfaces of the tube cover 24 and install it in the piston makin...

Страница 24: ...22 While FIRMLY HOLDING THE BALL TUBE 35 IN PLACE insert as many of the balls 9 through the opening in the ball tube as possible Rotate the input shaft 3 slightly to make room for each ball that is inserted Note As the spindle is rotated the ball tube may tend to rise out of the holes in the piston Continue to insert balls until ALL TWENTY SIX HAVE BEEN INSTALLED Figure 49 Lightly grease the seali...

Страница 25: ... that the rack teeth of the piston are visible in the side cover opening in the housing Figures 20 53 Make certain that the valve body is oriented in the housing so that the marks made during disassembly align Slide the piston and valve body assembly completely into the housing taking SPECIAL CARE not to damage the piston glide ring 14 and the valve body O rings 12 Secure the valve body 7 to the h...

Страница 26: ... Count the total revolutions in either direction and at the same time measure the average torque to rotate the shaft To obtain the proper preload adjustment rotate the input shaft 180 in both directions past the midpoint of piston travel The midpoint of piston travel is approximately one half the number of input shaft revolutions possible in a single direction Each time the direction of input shaf...

Страница 27: ...C 500N make certain that both externally adjustable steering limiting stems are adjusted out counter clockwise to within 5 turns of being removed then retest B Gauge pressure does not drop prior to axle stop contact in either turning direction and pump or gear relief pressure is noted upon axle stop contact If the steering gear being adjusted is a C 300N this reaction indicated the internally adju...

Страница 28: ...ue on the steering wheel for more than 5 seconds beyond the time the pressure relief setting has been reached It may damage the unit or cause the temperature of the oil to rise beyond 200 TESTINGTHEPOWERSTEERINGGEARFORINTERNAL LEAKAGE General Note Excessive internal leakage past seals and O rings will generally be manifested by an increase in steering effort especially when steering quickly to the...

Страница 29: ...g headings it is strongly recommended that some preliminary checks be made and a test ride be taken to eliminate unnecessary work 1 Check for proper and equal tire inflation on the steering axle Note any abnormal tire wear which may be attributable to front end alignment 2 Make certain the power steering reservoir oil level is correct 3 Make certain the power steering pump belt is not slipping 4 V...

Страница 30: ... valve 2 Replace piston and spindle assembly 3 Mechanical fault in vehicle steering 3 Overhaul and check in members not belonging to power accordance with vehicle service steering units manual 3 Power steering tends to 1 Faulty rotary valve 1 Replace piston spindle assembly turn by itself when engine is running 4 Excessive free play in 1 Power steering housing or housing 1 Retighten mounting bolts...

Страница 31: ...ident or breakdown in Check for damaged or worn parts the rotary valve unit 3 Bind in intermediate shafts 3 Determine cause and correct 4 Lower steering gear parts deformed 4 Replace the piston and spindle as a result of accident or breakdown assembly in the rotary valve unit 9 Power steering operates 1 Reservoir oil level low 1 Fill up to level but with noise 2 Piping contacting part of the body ...

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