PSG COLLEGE OF TECHNOLOGY BE FINAL YEARAUTOMOBILE YEARAUTOMOBILE ENGINEERING VEHICLE SERVICING AND MAINTENANCE
STEERING SYSTEM MAINTENANC AND SERVICING
S.R.RAVICHANDRAN S.R.RAVICHANDRAN 10A240 M.BALAKRISHNAN M.BALAKRISHNAN 11A431 S.SELLADURAI S.SELLADURAI 11A442
FACULTY SIGNATURE (M.P.BHARATHIMOHAN)
Ch!"#$ 1 1.1 T$%&'# Sh%%"*+ T#,h T!1.1.1 O!#$"%*
1.
M*& -"##$*+ +#$
A.
A mechanical means of steering control. 1. The steering wheel turns a shaft attached to the input shaft, which turns a spiral worm gear. The spiral worm gear turns an output shaft, which horizontally moves the pitman arm, drag link and steering arms, turning the front wheels.
2.
M*& -"##$*+ +#$ "h //#**+# ---" .
A.
A mechanical means of steering with a hydraulic control valve and a cylinder. 1. The hydraulic control valve is installed in the vehicle drag link. 2. Turning effort applied to the steering wheel actuates the valve, which, in turn, directs hydraulic fluid from the pump to the power cylinder located in the steering linkage.
3.
S#I*"#+$ -"##$*+ +#$
A.
A mechanical means of steering with a hydraulic control valve and a cylinder. 1. The hydraulic control valve is attached to the steering gear. 2. Ross hydropower steering gear a. Turning effort applied to the steering wheel overcomes the valve centering spring and hydraulic reaction which moves the valve spool, restricting the return port. This increases the flow to one of the cylinder ports, actuating one end of the piston giving hydraulic power to the linkage where the cylinder is attached. 3. aginaw steering gear a. Turning effort applied to the steering wheel turns the input shaft attached to a torsion !ar. "hen receiving resistance from the wheels the torsion !ar is twisted actuating
#.
I*"#+$ -"##$*+ +#$
A.
A mechanical means of steering with a hydraulic control valve and a cylinder com!ined into one component. 1. Turning effort applied to the steering wheel overcomes the valve centering springs or torsion !ar. The hydraulic reaction restricts the return port, increasing the flow to one end of the piston giving hydraulic power to the steering gear.
$.
P%#$ -"##$*+ !&!
A.
%ressure means work. &low means speed 1. The steering pump produces flow 'gallons per minute(. a. The faster or slower the steering wheels turn will determine how much fluid is re)uired. 2. The steering pump relieves pressure. a. The higher the pressure the steering gear can withstand the more work it can perform.
*.
P%#$ -"##$*+ $#-#$/%$
A. .
+ooling, supply, and filtration
P%#$ -"##$*+ h%-#-
A.
A means of transporting fluid
1.2 O* /#h,# &-"#*"-
1.
S#,"%$ -h5" &-"#*"
A.
+enter the steering wheels.
-.
Remove drag link.
+.
+enter the steering gear. 1. n steering gears with no timing mark on the sector, count the num!er of turns from full left to full right, come !ack half the num!er of turns.
2. n steering gears with a timing mark on the end of the sector, the mark should !e perpendicular to the centerline of the cylinder !ore. 3. n the Ross TA steering gears align the timing mark on the end of the sector with the timing mark on the housing. The timing mark on the sector should !e perpendicular to the centerline of the cylinder !ore. /. 0oosen sector shaft adusting screw am nut. . rasp the pitman arm and gently try to rotate it !ack and forth. 1. Attempt to feel the movement !etween the sector shaft and the piston inside the steering gear. 2. /o not attempt to move the piston or the worm shaft. &. Turn the sector adusting screw counter4clockwise if no movement is felt in the pitman arm. . Turn the sector adusting screw clockwise until no movement the pitman arm. . /o not over4adust or over4tighten, tighter is not !etter, adustment . &. Recheck pitman arm for lash.
&ig 1.1
2.
D$+* &-"#*"
Remove the drag link from the pitman arm.
+enter the steering gear.
Refer to sector shaft adustment
et the front steering tires straight ahead.
Adust the drag4link to the pitman arm without moving the pitman arm.
&ig 1.2
3.P$#--&$# R##5 6 U*%*+ V/# A&-"#*"
A.
The pressure relief5unloading valves are provided to reduce pressure when the wheels have reached the end of turn.
-.
The valves keep the pump from operating at ma6imum pressure relief when the steer wheels reach their steering limits.
+.
Adust a6le stops according to the manufacturer7s specs
/.
tart the engine and allow it operate at idle speed.
.
&ull weight of the vehicle must !e on the wheels.
&.
Turn steering wheel one direction until a high pressure hiss is heard or the a6le stop makes contact.
.
Turn the relief valve in or out until a high4pressure hiss is heard when there is 1584inch clearance !etween the a6le stops. 'ee diagram !elow(.
9.
Repeat the procedure steering in the opposite direction adusting the valve on the opposite end of the steering gear.
:.
Turning the adusting screws in increases the clearance !etween the a6le stops. Turning the adusting screws out decreases the clearance. 1.
n heppard steering gears / ;T screw the adusting screws out !eyond flush with the housing or a leak will occur.
&ig 1.3
&ig 1.#
4.R%-- TAS &"%", !%!!#" //# &-"#*". A. &or installation of new and remanufactured steering gears only.
1.
0ift front wheels off the ground.
2.
tart engine and let operate at idle. a. All linkage must !e connected at this point.
3.
teer wheels to full travel in one direction until the linkage firmly !ottoms against the a6le stop. '
#.
teer wheels to the other direction4repeating step 3.
7.R%-- TAS *& $#&-"#*" %5 !%!!#" //#-.
et a6le stops to vehicle manufacture7s wheel cut or clearance specifications.
tart the engine and let run for $ to 1= minutes to allow hydraulic fluid to warm up. Turn off engine
:f the steering gear is e)uipped with a fi6ed poppet !olt and washer at the lower end of the housing, it must !e replaced with an adusting poppet screw and sealing nut. ' The adusting screw will have to !e purchased separately, part >=21#=?1 for most gears(.
crew the sealing nut onto the drive screw until it is flush with the end of the adusting screw.
crew the adusting screw in until the sealing nut is firmly against the housing. Tighten the sealing nut.
0ift front wheels off the ground and check fluid levels.
!serve the end of the sector shaft for the direction of travel
tart the engine and let it run at idle.
;ote which timing mark is nearest to the housing piston !ore.
Turn the steering wheel in the direction that makes the timing mark move toward the adusting screw at the end of the housing. Turn in this direction until the a6le stop contact is made.
%ull hard on the steering wheel 'a!out #=l!s. of rim pull on a 2=4 inch diameter wheel( after the a6le stop contact is made.
Turn the steering wheel in the opposite direction until the other side a6le stop is contacted.
0oosen sealing nut and !ack out adusting screw 1 inch past the end of the sealing nut.
Tighten the sealing nut against the housing.
tart engine and let engine idle.
Turn the steering wheel in the opposite direction 'timing mark toward adusting screw( until the a6le stop contact is made.
9old the steering wheel in this position for no more than 1= seconds and release as many times as necessary while completing the ne6t two steps.
0oosen the am nut and hold it in place with a wrench.
Turn in the adusting screw in with an allen wrench using finger pressure only 'don7t use a ratchet( until the allen wrench stops turning. /o not attempt to turn in any farther. +aution@ Applying pressure to the steering wheel at the end of travel for more than 1= seconds may damage the steering pump.
-ack out the adusting screw 3415# of a turn and tighten the sealing nut.
The adusting screw must not e6ceed 14151* inch !eyond the sealing nut for proper thread engagement.
Tor)ue adusting screw sealing nut 3$4ft l!s
8. TR9 I*!&" Sh5" S# R#!,##*" 5%$ TAS G#$ /isconnect the return line from the steering. %lug off the return line and port of the gear with a high pressure fitting.
cap the return
•
Remove the steering column from the input shaft of the steering gear.
•
Remove the dirt and water seal from the steering gear.
•
"ipe out the grease to remove the spiral retaining ring. :nsert a screwdriver into the notch formed in the end of the ring. -e careful not to scratch the !ore with the screwdriver.
lip the steering column !ack onto the input shaft and install the pinch !olt, do not tighten.
"rap or tie a shop towel around the input shaft area and place a drip pan under the vehicle to catch the oil.
+heck the fluid level and add as necessary.
Remove the shop towel, check to !e sure the seal was forced out.
Remove the steering column and remove the input shaft seal.
+heck for and remove any seal fragments left in the seal area.
Apply clean grease on the inside diameter of the new input shaft seal.
"ith the small diameter of the input shaft seal installer against the seal, tap the tool until the tool shoulder is s)uarely against the valve housing 'seal installer tool will have to !e purchased separately(.
Ch!"#$ 2 2.1 F&-h*+ "h# -"##$*+ -:-"#
/isconnect the return line from the reservoir. %ut in a container and wheels off the ground.
0ift front
plug off the reservoir.
/isengage the ignition.
ngage starter while turning wheels from left to right.
/o not allow the reservoir to run out of fluid.
Reattach return line to reservoir.
Recheck fluid level.
2.2 F*+ * $ '##*+ "h# -:-"#
&ill the reservoir nearly full, start and run engine for 1= seconds.
+heck and refill the reservoir.
Repeat this at least three times. /o not allow reservoir to run out of fluid. This may induce air into the system.
tart the engine and let idle for two minutes. Then turn off the engine. o
Recheck the fluid level.
0ift the front wheels off the ground.
tart the engine and let idle.
teer front wheels full left then full right to complete !leeding.
The relief5unloading valve adustment should !e implemented !efore completing this process.
+heck if the gear is mounted in an inverted position with a manual !leed screw.
:f e)uipped with a manual !leed screw turn full left to full right several times.
Ch!"#$ 3 3. P$#--&$# * F% T#-"*+ "h# S"##$*+ S:-"# 3.1 P&! T#-"*+;
tart engine and check fluid level assuring that oil flow is in proper direction through the flow meter.
%lace thermometer in reservoir.
teer from lock to lock several times to allow system to warm up. '1#= to 1*= degrees f. (
At idle speed slowly turn the shutoff valve until closed, reading the pressure at which the pressure relief valve opens. uickly open the valve to avoid heat !uildup or possi!le damage.
C&"%*@ :f the pressure rises rapidly or is uncontrolla!le do not co mpletely close the valve. /amage may occur or hoses may rupture.
Read the flow at idle and at 1$== rpm in a stationary position. 'The flow must not !e a!ove the ma6imum flow specification(.
At idle turn the steering wheel full left and full right o!serving the flow rate. 'The flow must not drop !elow the minimum allons %er
;ormal !ackpressure will !e $= to $ %: with the engine idling and the steering wheel stationary. +heck at normal operating temperature
3.2 S"##$*+ G#$ I*"#$* L#+# "#-"
"ith engine running steer the vehicle to the left.
%lace a one inch spacer !lock long enough to keep fingers clear, !etween the a6le and a6le stop 'to prevent the operation of the unloading5poppet valves(.
Apply 2= l!s. to the rim of the steering wheel to !e sure the control valve is fully closed.
The pressure relief valve should read pump relief p ressure as noted in the pump test.
The flow should range from = to 1 %<.
:f the flow e6ceeds 1gpm check for an au6iliary gear or cylinder, disconnect and repeat the test.
3.3 S"##$*+ C%&* M*"#**,# The steering column is pro!a!ly the most overlooked area in steering system maintenance.
Behicle will continue to steer !y itself after an initial turn is started.
Behicle will wander
Behicle will stay steering wherever the steering wheel is put.
teering wheel will lock up or hang up every )uarter of a tur
&ig 3.1
3.4 S"##$*+ C%&* Ch#,
/o these steps with the vehicle on the ground and engine off.
%ull around the steering wheel a!out # to $ inches the steering wheel must spring !ack.
:f the steering wheel will not spring !ack install an inch pound tor)ue wrench on the column nut at the steering wheel. Record the readings from the tor)ue wrench steering full left to full right.
:f the tor)ue wrench fluctuates more than 1$ inch pounds from right to left you have a u4oint or timing pro!lem.
ne greaseless u4oint cap or improperly installed cap may cause this pro!lem. The entire steering column may have to !e removed to find this pro!lem.
The u4oints are designed to operate !est at a ma6imum of 2$ degrees !etween the drive shaft and the driven shaft.
:f the steering column is not timed properly it will also cause this pro!lem. n most steering columns there are arrows to show the proper phasing. "hen no arrows are present, make sure the column yokes are in line to maintain proper timing.
:f proper timing still has not !een accomplished rotate the two piece shaft one spline at a time until the tor)ue reading is the same through the rotation of the wheel.
:nstall an inch pound tor)ue wrench on the gear, :f the readings !etween the gear and the steering wheel, is more than 1=inch pounds you still have a steering column pro!lem. 4
+heck the slip4yoke to !e sure it is not frozen tight and that the u4oints are moving properly.
4
+heck the steering column slip4oint making sure it has movement within itself.
Ch!"#$ 4 4.0 POSSIBLE STEERING PROBLEMS AND CAUSES
4.1 ROAD 9ANDER 4 Tire pressure incorrect or une)ual left to right. 4 +omponents in steering linkage loose or worn 'teering wheel to road wheel(. 4 "heel !earings improperly adusted or worn. 4 &ront end alignment out of specification. 4 /ry fifth wheel or poor finish on fifth wheel or trailer plate.
4.2 NO RECOVERY 4 Tire pressure low 4 &ront end components !inding 4 &ront end alignment incorrect 4 Tight front a6le king pins 4 /ry fifth wheel or poor finish on fifth wheel or trailer plate 4 teering column !inding 4 %ump flow insufficient 4 teering gear improperly adusted 4 teering gear control valve sleeve sticking
4.3 SHIMMY 4 -adly worn or unevenly worn tires 4 :mproperly mounted tire or wheel 4 "heel !earings improperly adusted or worn 4 +omponents in steering linkage loose or worn 4 "heels or !rake drums out of !alance 4 &ront end alignment incorrect 4 Air in the hydraulic system
4.4 E
4.7 OVERSTEERING OR DARTING 4 /ry fifth wheel or poor finish on fifth wheel or trailer plate 4 &ront end components !inding or loose 4 teering column !inding 4 teering gear improperly adusted 4 teering gear control valve sleeve sticking 4 Rear a6le mounts 'rear steer (
4.7 HIGH STEERING EFFORT IN ONE DIRECTION 4 Cne)ual tire pressure 4 Behicle overloaded 4 :nade)uate hydraulic system pressure 4 6cessive internal leakage in one direction of turn only
4.8 HIGH STEERING EFFORT IN BOTH DIRECTIONS 4 0ow tire pressure 4 Behicle overloaded 4 0ow hydraulic fluid level 4 0ow pressure or flow from pump 4 +omponents of steering system !inding 4 Restriction in return line, or line too small in diameter 4 6cessive internal leakage 'verify with internal leakage test ( 4 versize tires 'check manufacturer7s specifications(
4.= LOST MOTION (LASH) AT THE STEERING 9HEEL 4 teering wheel loose on the shaft 4 0oose connection !etween the steering gear, intermediate column, and steering column 4 teering gear loose on frame 4 %itman arm loose on output shaft 4 +omponents in steering linkage loose or worn 4 teering gear improperly adusted 4 &ront spring !ushing
4.> E
4 6cessive pump flow 4 Behicle overloaded 4 Cndersized replacement hose or line
