W&C SL20K User manual

W&C214
REV
03
.
01
.201
7
1. Introduction ____________________________1
1.1InstallerResponsibility_______________ 1
2. BeforeYou Begin________________________1
2.1SafetyExplanations _________________ 2
2.2Warning__________________________ 2
2.3Identifying YourModel_______________ 2
3. RideHeight_____________________________3
3.1CalculatingRide Height______________ 3
4. Installation_____________________________4
4.1MountingtheSuspension_____________ 4
4.2AdjustingMaximumTurnAngle________ 8
4.3AdjustingWheel Toe-in______________ 9
5. TorqueRequirements___________________10
5.1Torque Guidelines _________________ 11
6. AirPressurevs.LoadGuide______________13
SL2065 Series PressureChart___________ 13
7. PartsList_____________________________14
8. Service Kits___________________________19
9. Quick-changeRideHeight_______________21
10. Preventive MaintenanceError! Bookmarknotdefined.
TABLEOF CONTENTS

SL20KSelf-Steering Axleand Suspension SystemInstallation Manual
1
1.Introduction
Thispublicationisto acquaint and assistyouin
installing and operating the Watson &Chalin
AuxiliarySteerableLiftableAirRide Suspension
ProductLine and isintended foruseonlywith
thisProductLine.
Thismanualincludesinstallationandoperating
information on Watson &Chalin modelnumbers:
SL-2065
Watson &Chalinreservesthe right to changeits
productsormanualsat anytime. ContactWatson
&Chalinat 1.800.445.0736 forinformation on
recent changesto products.
Defectivecomponentsshouldbe returnedto
Watson &Chalinwithapre-arrangedReturned
GoodsAuthorization (RGA)numberthrough the
warrantydepartment. If the defectisin
compliancewithwarrantyconditions,the
defective component maythen be replaced.
Ifthe partisdamagedinshipment, please
contactthe freight companytofileaclaim.The
freight companyisresponsible foranydamage to
componentsduring shipment.
IMPORTANT
The entiremanualmustberead and understood
beforeproceeding with installation orserviceof
anycomponents.
Thismanualshouldbe used inconjunction with
corresponding drawingsthat comewith Watson
&Chalin suspensionsupondelivery.
The vehiclemanufacturermustapproveany
changestothevehicleframebeforethe changes
aredone.Cuttingoraltering the vehicle’sframe
isnormallynotpermitted bythemanufacturer
and affectsthe manufacturer’swarranty
coverage.
1.1InstallerResponsibility
The installerofthe suspension systemmust:
•Ensurethatthevehiclefunctionsproperly
with the increased weightofan additional
axle.
•Determine thecorrectlocationofthe
suspensionto provide the propervehicleload
distribution astonotexceed therated
capacityofthecomponentsinvolved.
•Ensuretheinstallation ofthe correctbrake
systemcomponentsto guarantee proper
braking performance. Brakeinstallation must
complywith FMVSS121 specifications.
•Ensurethat properclearanceexistsbetween
the drive shaft and the auxiliaryaxle.
•Ensuresuspensionoperateswithinrun
range.
2.BeforeYou Begin
Beforeyoubegintoinstall the Watson &Chalin
suspension system,youmust:
•Checkspecificationson suspensionsystems
to be surethat thecorrectsuspension
systemwaschosen forthevehicle.
•Verifythe vehicleframewidthiswithinthe
allowablemounting range ofthe suspension
and that thevehiclecrossmembers are
correctlypositioned.
•Markthe locationofthesuspensionside rails
and checkforinterferenceswith existing
bracketryand components.
•Checkforinterferencebetweentheaxleand
drive shaft.

SL20KSelf-Steering Axleand Suspension SystemInstallation Manual
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•Ensuresuspensionoperateswithinthe run
range.
2.1SafetyExplanations
Watson &Chalinusesthe followingtypesof
notestowarnagainstpossiblesafetyproblems
and to giveinformation that helpsto prevent
damage to equipment.
IMPORTANT
Animportant message indicatesaprocedurethat
should befollowedexactly.
Awarningindicateshazardsorunsafepractices
that couldresultinseverepersonalinjuryor
death, ifthe procedureisnot followedexactly.
Allsafetystatementsshouldbe read carefullyto
prevent bodilyinjury,to assurethat partsare
assembled properlyand toretainthe
manufacturer’swarranty.
2.2Warning
Properaxleattachmentrequired forsafe
operation ofthe vehicle.
No alteration ofanyWatson&Chalinsuspension
componentsispermitted without proper
authorization fromqualified Watson &Chalin
personnel.
No welding ofanysuspension componentsis
permitted except when specified byWatson &
Chalin.
2.3Identifying Your Model
IMPORTANT
It isimportant that you knowwhat modelnumber
hasbeen assignedto yourassemblyincaseyou
everneed to contactWatson &Chalin.
Identification Plate
Eachsuspensionassemblyhasan identification
platelocated on theleftside railassembly.This
ison the driver’sside ofthe vehicle. The plate
includesthe modelnumber,serialnumberand
capacityinpoundsforthe assembly.Itis
important torecordthe modelandserialnumber
forfuture reference.
FIG
–
1 Identification Plate

SL20KSelf-Steering Axleand Suspension SystemInstallation Manual
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3.RideHeight
RideHeight, alsoreferredto asRunHeight, is
the distancebetween thesuspensionmounting
surface, orthebottomofthe vehicleframeand
the spindlecenterofthe auxiliaryliftableaxlein
the loweredrunposition. It isoneofthemost
important dimensionstoobtainandwhenset
properly,allowsfortheoptimumamount oflift
that the axle can achieve.
IMPORTANT
Acorrectinstallation requiresthat the suspension
ride heightbewithintherangespecifiedonthe
correspondingdrawingwhen the vehicleisinits
loaded condition.
Watson &Chalinprovidesnumerousdifferent SL
seriessuspensionsystemsto accommodate
different vehicle ride heightsand capacities.
3.1Calculating RideHeight
ProperRide Height iscalculated with the
following equation:
Ground to Bottomof
Vehicle Frame (loaded)______________
StaticLoaded Tire Radius– ______________
RideHeight=_______________
** The SL2065 seriesisequipped with theW&C
quick-change ride height system. Ifit is
determined above that a ride height change is
necessaryand the resultingrun height fallswithin
a designed allowablerange, referto the Quick-
changeRide Height sectionon page21 for
detailson changing spacers.
FIG
–
2 Ride Height

SL20KSelf-Steering Axleand Suspension SystemInstallation Manual
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FIG
–
3
Pusherand TagAxle Alignment
4.Installation
The following instructionsareforinstalling the
componentsofthe Watson&ChalinSLSeries
Suspensionsystems.All modelnumbers inthe
seriesareinstalled usingthe sameset of
instructions.Watson &Chalinassumesthat the
correctauxiliarysuspension and axlewere
chosen based on the individualdesign criteria.
The suspension systemsmustbe installed with
the properamount oftire-to-groundclearanceto
ensuretroublefree operation ofthe vehicle. If
thereistoomuchground clearance, the
suspensionwillnot carryitsshareofthe load,
straining theothersuspension components.
When thereistoolittleground clearanceorifthe
suspensionisoverloaded, the vehiclewill bottom
out whilegoingoverbumpsand damage can be
doneto the suspensioncomponentsorother
componentson the vehicle.
4.1Mounting theSuspension
Before mounting the suspension, you must:
•Confirmthat the propersuspensionand axle
waschosenbased onyourcompany’s
specifications.
•Ensurethechassisframehasthe proper
crossmemberreinforcement inthearea
wheretheauxiliaryaxlehanger/railis
located. SeeFigure 4.
•Ifthe vehicleframewaspredrilled for
mounting the SLseriesaxlepriorto
purchase, be sureto alignto and usethese
fastenerpositions.
•Alsorememberto removetheassociated
boltsfromthe framepriorto axlealignment
and installation.

SL20KSelf-Steering Axleand Suspension SystemInstallation Manual
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NOTE
Throughouttheinstallationprocess you must
checkfrequentlyforsuspension clearance
problemswhile mounting the suspension.
FIG
–
4
Chassis CrossmemberReinforcement

SL20KSelf-Steering Axleand Suspension SystemInstallation Manual
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Tomount the suspensionto the vehicle:
1. Placethevehicleon alevelsurface.
2. Markthe approximate locationofthe
suspensionside railassemblieson the
vehicleframe rails.
3. Checkforinterferencewith anyexisting
bracketsormounting bolts.
4. Locate the auxiliaryaxle mountingposition.
5. Fromthe centerlineofthe axleat thewheel
center,markthe location ofthisaxle
measurement on theoutside ofthevehicle
frame rail.
6. Raisethebackend ofthe frameusing either
alift, jack ordrivingthe rearaxlesand tires
onto a lift.
7. Raisethe suspensioninto position using the
marked axle, front hangerrail andupperbag
plate centerlineaslocators.
NOTE
If,whileraisingthe SLseriessuspension into
place,thehangers getstuckon the frame
becausetheyaretoonarrow,loosen the boltson
one sideofthe crossmember.Thiswill allowthe
hangers to separateenough tomoveinto
position. Ifyou haveawelded crossmemberyou
willnot be ableto loosen inthisway.
8. Using clamps, clamp the suspension railto
the vehicleframe rail.
IMPORTANT
Boththesideand bottommountingsurfaces
mustsitflushwith theside and bottomofthe
vehicleframerailsorspacers,orthe suspension
warrantyisinvalid.See Figure 6.
FIG
–
5
Suspension
M
ounting
Position

SL20KSelf-Steering Axleand Suspension SystemInstallation Manual
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9. Markthe locationofthe mounting holeson
the outside ofboth suspension frame rails.
10.Inspectvehicleframerailsforanyitemsthat
maycause drilling obstructions.
Welding, drillingorboltingthroughthe bottom
flange ofthe suspension frameorvehiclerails
voidsthe manufacturer’swarranty.
NOTE
3/4”SAEGrade8UNFfasteners requiredto
attachtheSL2065suspensiontothevehicle
frame.
11.Drilltwo 13/16”holesthrougheach
suspension railand vehicleframe rail.
12.Fasten eachsuspensionside rail to the
vehicleframeusing the appropriate
size/gradefastenerspecified above, flat
washerand locknut. Useat least2boltsper
side.
13.Drill remaining mountingholespersiderail.
SeeFigure7orthesuppliedsuspension
drawing forrecommended fastenerquantities
and locations.
14.Installthe remainingbolts,washers and lock
nutsandtighten capscrewsto propertorque.
See“Torque Requirements” on page13 for
details.
15.Drillaminimumoftwo13/16”diameterholes
throughtheupperairspring mounting
bracketsand chassisframe.
16.Fasten eachbagplateassemblywithtwo¾”
SAEgrade 8UNFfine thread cap screws,
flat washers and locknutsasseen infigure
7.
NOTE
Hangers mustbe parallelto oneanotherto
ensure properoperation.
FIG
–
6
Frame
Alignment

SL20KSelf-Steering Axleand Suspension SystemInstallation Manual
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17.Attachcrossmemberto the suspension front
hangers with suppliedfasteners and tighten
to specified torque values.
18.Removethe clampfromthe vehicleframe
rails.
4.2Adjusting Maximum Turn Angle
Thissection isused to check and adjust, if
necessary,themaximumturnangleofyour
SL2065 suspension system inordertoobtain
properclearance.
Toadjustthe maximum TurnAngle:
1. Measurethe current Turn Angle.
2. The maximumturnangleforSL2065Series
modelisnormallyset at the maximum25º.
Someapplicationsmayrequireless turn
angle.
3. Ifthe turnangleneedstobeadjusted,adjust
the stopboltuntil the correctangleis
obtained on both sides.
4. To obtainthemaximumTurn Angle:
a. Loosen the stop boltjamnut asseenin
Figure8.
b. Adjustthe turnanglebyadjustingthe
stop boltinorout.
c.Tighten the jamnut to 50-75 lbs./ft.
Do not turnthestopboltsomuchthat the bolt
end protrudespastthe brakespiderasthiscan
cause damage toothercomponents.
FIG– 7 RecommendedFastening Method
FIG– 8 Stop BoltLocation

SL20KSelf-Steering Axleand Suspension SystemInstallation Manual
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4.3Adjusting WheelToe-in
Toe-inisthe relationshipofthe distancebetween
the front andrearofthe tiresorthe amount at
whichthefront wheelspoint inward. Toe-out is
the amount at whichthetirespointoutward.
When the front distanceis less than the rear
distance,thewheelsareina“toe-in”condition.
Mosttireweariscaused byincorrecttoe settings.
Toe-inmustbe verified andadjusted,ifrequired,
during suspensioninstallation.
To adjust wheelToe-in:
1. Placethevehicleon alevelsurface.
2. Lift the axleuntil tiresarefree tospin.
3. Usepaint orchalkto markthe horizontal
centeroftiresaroundthecomplete outer
surface ofthe tire.
4. Placethe pointers ofatrammelbaron the
marks of eachtireand rotatethe tiresmaking
sure a straight line hasbeen marked.
5. Measureandrecordthedistanceattheback
ofthe tires.
6. Measureand recordthedistanceat the front
ofthe tires.
7. Usethe following calculationto determine the
Toe-in measurement.
Distancebetweenbacktires(R)__________
Distancebetweenfront tires(F) –__________
Toe-in must be “0.09”+or– “0.03”.=________
NOTE
ApositiveresultisconsideredToe-inanda
negative resultisconsidered Toe-out.
8. Ifthe Toe-inmeasurement isnot at the
specified distance:
•Loosen clampboltsand nutsat eachend of
the tie rod.
•Turntierod tube with apipewrenchto adjust
wheelToe-in.
•Tighten clamp boltsto the propertorque.
9. Repeat step 1through step 8until correct
Toe-in isobtained.
FIG
–
9 Toe
-
in