study guide international p s international pros series

®

A NAV I STAR C O M PANY

Study Guide International ® ProS

tar® Series: Front Air Suspension and Axle Assem

bly TM

T-100821

International® ProStar® Series

Front Air Suspensionand Axle Assembly

Study GuideTMT-100821

©2010 Navistar, Inc.4201 Winfield Road, Warrenville, IL 60555

All rights reserved.

No part of this publication may be duplicated or stored in an information retrieval system without the express written permission of

Navistar, Inc.

Table of ContentsIntroduction .......................................................................3

Module 1: System Operation .........................................5Overview ................................................................................................ 5Height Control Valves (HCVs) .......................................................... 5Air Springs ............................................................................................. 6Shock Absorbers ................................................................................. 6Torque Rods & Sway Bar ................................................................... 7Transverse Torque Rod & Crossmember ........................................ 7Kingpin/Steering Knuckle Assemblies ............................................ 8

Module 2: Diagnostics .................................................. 11Vehicle Walk-Around ......................................................................... 11Air Leaks ............................................................................................... 11Ride Height Measurement & Adjustment ..................................... 11Sway Bar, Clamps/Torque Rods & Bushings .............................. 13Kingpin/Steering Knuckle Assemblies .......................................... 14

Kingpin Binding ........................................................................ 14Worn Steering Knuckle Bushings ........................................ 14Steering Knuckle Vertical End Play ...................................... 15

Module 3: Service Procedures ....................................17Decreasing Caster ............................................................................. 17Increasing Caster ............................................................................... 18Sway Bar Removal ............................................................................. 18Sway Bar Installation ......................................................................... 19Air Spring Removal ............................................................................20Air Spring Installation ........................................................................ 21Steering Knuckle Disassembly ....................................................... 21Kingpin Preparation & Measurement .............................................22Steering Knuckle Bushing Removal ............................................... 24Steering Knuckle Bore Measurement ........................................... 24

Table of ContentsSteering Knuckle Bushing Installation ...........................................25Steering Knuckle Bushing Reaming ..............................................26Kingpin Seal Installation ...................................................................27Steering Knuckle Reassembly ........................................................28

Conclusion .......................................................................33

Introduction 3

Introduction

Welcome to the International® ProStar® Front Air Suspension and Axle Assembly program. This comprehensive training, along with a proven certification program, provides technicians and dealers with all the expertise needed to effectively service and maintain the International® ProStar® Front Air Suspension and Axle Assembly.

To receive credit for completing this program, you are required to take a post-test.

Objectives

After completing this program, you will be able to:

• Identify the components that make up the International® ProStar® front air suspension and axle assembly.

• Diagnose problems associated with the suspension.

• Perform maintenance and service procedures to keep the suspension operating effectively.

NOTES

4 International® ProStar® Series: Front Air Suspension and Axle Assembly

Module I: System Operation 5

System Operation

Overview

The International® ProStar® features a multilink front air suspension rated at 12,000 lb. The suspension adjusts to load changes automatically. This provides a “low rate” suspension with light or no loads and a “higher rate” suspension with heavy loads.

Let’s take a look at the various components that make up this state-of-the-art suspension system.

Height Control Valves (HCVs)

The Height Control Valves, or HCVs, control ride height using compressed air. Air is routed from the manifold on the air dryer to a T-fitting on the right frame rail.

From there, each HCV supply port is supplied individually. Air lines from the HCVs to the air springs allow the control of supply and exhaust air independently.

A valve lever on each HCV is connected to the axle assembly with a height control rod. This lever responds to frame height and automatically fills or

Module I

“The suspension adjusts to load changes automatically.”

“This lever responds to frame height and automatically fills or exhausts the air springs to maintain the correct ride height.”


exhausts the air springs to maintain the correct ride height.

Air Springs

The air springs of the multilink front air suspension replace steel springs, so there is no inter-leaf friction to overcome. This minimizes road shock transferred to the frame, cargo, and driver. The air springs support the vertical load while providing a very low spring rate.

The snap-on mount and quality-connect fittings make removing and installing the air springs quick and easy.

Shock Absorbers

The suspension is equipped with one shock absorber on each side of the vehicle. Shock absorbers mechanically dampen spring oscillation caused by bumps and rough terrain. Spring compression and extension forces are absorbed and dissipated through them. Shocks also eliminate excessive tire wear. They are especially effective when the vehicle is empty or only partially loaded.


Torque Rods & Sway Bar

Dual torque rods are mounted between the front mega brackets and axle brackets on each side of the vehicle. The multilinked design provides stability by minimizing axle movement caused by road bumps and load transfer during braking. The lower torque rods are used when adjusting caster. The mega brackets are also used for mounting of the radiator and front tilt bumper assembly. The procedures for checking and adjusting the toe-in setting can be found on ISIS®.

The sway bar mounts to the lower torque rods with two sway bar clamps on each side. The sway bar helps reduce vehicle lean during cornering and stabilizes the chassis.

Transverse Torque Rod & Crossmember

The transverse torque rod is an integral component of the multilink front air suspension that enhances handling during cornering and helps maintain lateral axle position.

One end of the transverse torque rod is mounted to a transverse cross-member on the frame. The other end is

Camber is not adjustable on the International® ProStar®.

Note

“The sway bar helps reduce vehicle lean during cornering and stabilizes the chassis.”


connected to the rear side of the front axle.

Kingpin/Steering Knuckle Assemblies

A two-piece steering knuckle allows the kingpin bearings and bushings to be replaced without removing the kingpin. The kingpins are permanently installed and therefore not serviceable. If either kingpin fails, the complete axle must be replaced.

“A two-piece steering knuckle

allows the kingpin bearings and

bushings to be replaced without

removing the kingpin.”

NOTES


Module II: Diagnostics 11

Diagnostics

Vehicle Walk-Around

To begin front air suspension diagnostics, verify any customer complaints first, by:

• test driving the vehicle• checking for uneven or unusual tire

wear• inspecting for broken, loose or

leaking shocks• checking for proper rear frame

angle

Air Leaks

Inspect the HCV supply lines for any damage. To check for air leaks, apply a soap solution to the lines at the fittings and anywhere there are signs of damage. Next, inspect the lines and fittings from the HCVs to the air springs for any damage. Apply a soap solution to the lines and fittings at the air springs to check for leaks. Inspect the air springs for any signs of damage.

Ride Height Measurement & Adjustment

With the vehicle parked on a smooth, level surface check ride height by first releasing the parking brake. Let air

Module 2


pressure build to governor cut-out and shut off the engine.

Remove the bolt, washer, nut and height control rod from the valve lever.

Release air from the air spring by rotating the lever to the exhaust position.

Reconnect the height control rod to the valve lever and allow the HCV to refill the air spring.

Measure ride height between the bottom mount surface and the top mount surface of the air spring. If the measurement does not meet the specification found on ISIS®, the HCV needs to be adjusted.

To adjust the HCV, insert a suitable tool into the alignment hole. Loosen the valve lever screw and push the lever up until the correct ride height is reached. If ride height is too high, drop the lever position to exhaust enough air to lower the ride height to a point below the correct height, then push the lever position up and refill to the appropriate height specification.

Finally, with the alignment tool still in place to prevent the valve from moving,

The multilink front air suspension has an HCV on each side. Make sure you perform the following steps on both sides of the suspension.

Note

Make sure the HCVs are cycled completely before and after any ride height adjustments. Cycling the HCVs ensures accurate measurements.

Note

When adjusting HCVs, complete the procedure only by adding air to reach the correct ride height.

Note

When making adjustments to the air ride height, a second technician is recommended for measuring the resultant ride height.

Note


tighten the valve lever screw to the specification found on ISIS®.

Sway Bar, Clamps/Torque Rods & Bushings

With the vehicle parked on a level surface and the wheels blocked, raise the vehicle and support the front end at the frame rails using a pair of suitable jack stands. Deplete any air from the springs and proceed with the following procedures.

First, inspect the sway bar and sway bar clamps for any signs of damage. Check for any loose or missing clamps or bolts.

Next, inspect the lower torque rods for any signs of damage. Also, inspect for loose or missing mounting bolts and worn bushings at each end.

Repeat these steps for the upper torque rods, mounting bolts and bushings at each end.

Inspect the transverse torque rod and crossmember for damage. Also, check for loose or missing mounting bolts and worn bushings at each end.

Finally, reconnect the control rods to the valve levers on both HCVs before

A jack must NEVER be used alone to support a vehicle. Always support the vehicle with suitable jack stands.

WarNiNg!

The vehicle must be unloaded and at approximate air spring height before performing this procedure.

Note


proceeding. Raise the vehicle and remove the jack stands from the frame rail.

Kingpin/Steering Knuckle Assemblies

Kingpin Binding

With the vehicle parked on a level surface and the wheels blocked, raise the vehicle high enough so the tires are off the ground and support the front axle using a pair of suitable jack stands.

Disconnect the drag link from the left steering knuckle. To check for steering knuckle-to-kingpin binding, turn the wheels by hand approximately 30 to 45 degrees from the straight-forward position and release them to see if they return to straight-ahead center.

Failure to do so indicates a binding condition. Reconnect the drag link to the left steering knuckle before proceeding.

Worn Steering Knuckle Bushings

Next, check for worn steering knuckle bushings. Mount the magnetic base of a dial indicator onto the axle beam with the stem of the indicator against the inside of the upper steering knuckle. Zero the dial indicator. Push


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in on the top of the tire and measure the movement between the steering knuckle and kingpin.

Movement greater than the specification found on ISIS® indicates the bushing is worn. If so, both upper and lower bushings need to be replaced.

If the movement is within specification, repeat this procedure for the lower steering knuckle bushing.

Steering Knuckle Vertical End Play

Next, steering knuckle vertical end play needs to be checked. Mount a dial indicator onto the axle beam. Place the stem of the indicator against the top of the upper steering knuckle. Using a jack, raise the front axle, and zero the dial indicator. Then, remove the jack stands and lower the vehicle.If vertical end play is greater than the specification found on ISIS®, the upper steering knuckle needs to be adjusted. The steps to adjust vertical end play are shown in the steering knuckle re-assembly procedure found later in this program.

Repeat the procedures to measure steering knuckle bushing wear and vertical end play on the other side of the vehicle.

If no obvious problems are found after performing the previous inspections, use the appropriate alignment equipment to measure all angles. Compare your findings to the specifications found on ISIS® and correct as needed.

Note

NOTES


Module III: Service Procedures 17

Service Procedures

Decreasing Caster


To decrease caster, loosen the two locknuts from the lower torque rod-to-axle mount bracket studs.

Pry the lower torque rod forward. Install the appropriate shim between the lower torque rod and the axle mount bracket.

Retighten the locknuts on the lower torque rod-to-axle mount bracket studs to the specification found on ISIS®.

Module 3


WarNiNg!

The toe-in adjustment must be checked after completing the caster adjustment.

CautioN!


Note

Both lower torque rods must be loosened at the axle mount brackets before installing any shims.

Note


Increasing Caster

To increase caster, loosen the two bolts and nuts that connect the lower torque rod to the mega bracket.

Pry the lower torque rod forward. Install the appropriate shim between the lower torque rod and the mega bracket.

Retighten the lower torque rod and mega bracket nuts and bolts to the specification found on ISIS®.

Once caster has been adjusted, build pressure in the air springs and remove the jack stands from the frame rails.

Sway Bar Removal


Remove the forward sway bar clamp nuts, bolts and clamp halves. At the rear sway bar clamp assembly, first loosen the upper bolt without removing the nut.

Both lower torque rods must be loosened at the mega bracket before installing any shims.

Note

The toe-in adjustment must be checked after completing the caster adjustment.

CautioN!


WarNiNg!


Note


Remove the nut from the lower bolt while leaving the bolt in place. Repeat these steps for the other side of the vehicle. With the assistance of a second technician, remove the lower bolts and remove the sway bar from the clamps.

Sway Bar Installation

With the assistance of another technician, install the sway bar into the rear sway bar clamps that were left on both lower torque rods and install the lower clamp bolts. Do not tighten the bolts at this time.

Install the forward sway bar clamps, bolts and nuts on both lower torque rods and the sway bar. Do not fully tighten the bolts at this time.

Ensure that the top of the rear sway bar clamp assemblies align with the alignment beads located on each lower torque rod.

Tighten all the bolts, making sure there is an even gap at the top and bottom of each clamp by alternating between the lower and upper clamp bolts.

Finally, tighten the bottom bolts and then the top bolts to the specification

The lower bolts of the sway bar clamps are longer than the upper bolts.

Note

When properly installed, an even gap must be visible along the bottom and top of each sway bar clamp.

Note


found on ISIS®. Repeat these steps on the other side of the vehicle.

Once the sway bar is installed, build pressure in the air springs and remove the jack stands from the frame rails.

Air Spring Removal

Remove the bolt, washer, nut and height control rod from the valve lever. Next, remove the bolt and nut from the bottom of the shock absorber and axle mount bracket. Set the HCR and mounting bracket aside.

Wipe the line and fitting clean, then remove the air line from the fitting at the top of the air spring. Cap the line and fitting. Remove the air line fitting from the air spring and cap the openings. Remove the upper mounting nut and washer from the air spring.

Remove the air spring by placing a pry bar between the air spring and the axle mount bracket. Pry the air spring up to release the snap-on mount from the axle mount bracket. You may need to pry several sides of the air spring to remove the snap-on mount. Once released, compress the spring to remove it.


WarNiNg!

If the air spring has a leak and is deflated, the air must still be exhausted from the system.

Note

To ease air spring replacement, support the front of the vehicle by the frame rails with suitable jack stands at approximate air spring height.

Note

Make note of the position of the Height Control Rod, or HCR, mounting bracket prior to removal so it can be properly reinstalled.

Note


Air Spring Installation

Compress the air spring, position it in place and align it with the top mount bracket. Secure the air spring snap-on mount to the axle mount bracket.

Install the air spring upper mounting washer and nut. Tighten to the specification found on ISIS®.

Remove the cap from the air line fitting and apply sealant to the threads of the fitting.

Install the air line fitting into the air spring. Remove the remaining caps from the air line and fitting. Connect the air line. Compress the shock and install the lower bolt. Properly install the HCR mounting bracket. Then install the washer and nut and tighten to the specification found on ISIS®. Install the height control rod to the valve lever with the bolt, washer and nut.

Build system air pressure to governor cut-out pressure and check for leaks. Check ride height as shown previously and adjust as necessary.

Steering Knuckle Disassembly

With the vehicle parked on a level surface and the wheels blocked, raise


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the vehicle high enough so the tires are off the ground and support the front axle using a pair of suitable jack stands.

Remove the wheel and hub assembly.Remove the brake components from the steering knuckle. Finally, remove the tie rod assembly.

Remove the drag link from the steering knuckle, if necessary.

After properly supporting the bottom steering knuckle, remove the two cap screws that connect steering knuckle halves.

Remove the upper steering knuckle by sliding it up, off the kingpin. Using a suitable tool, remove the shim.

To remove the lower steering knuckle, remove the support and slide it down, off the kingpin. Then remove the thrust bearing and discard it.

Kingpin Preparation & Measurement

Start by wiping all grease and debris from the upper and lower ends of the kingpin. Using a fine grit emery cloth and parts solvent, polish the upper end

The steering knuckle must be supported before removing the cap screws.

WarNiNg!

Apply a light coat of oil to all cleaned and dried parts that are to be reused. Do NOT apply oil to the brake lining or the brake drums.

CautioN!

Solvents can be flammable, poisonous and caustic. Take appropriate safety measures when cleaning parts with solvents.

WarNiNg!


of the kingpin. Repeat this procedure for the lower end of the kingpin.

Inspect the upper end of the kingpin for wear or damage. Use a micrometer to measure the top of the kingpin in two locations and 90 degrees apart. If the kingpin does not meet the specification found on ISIS®, the axle must be replaced. If the upper end is within specification, repeat this procedure for the lower end of the kingpin.

Do NOT clean ground or polished parts in a hot solution tank or with water, steam or alkaline solutions.

CautioN!

Do NOT attempt to remove the kingpin. It is a non-replaceable component of the axle assembly.

CautioN!

Parts must be dried immediately after cleaning. Dry parts with clean rags or compressed air.

CautioN!

Always use an appropriate solvent to clean ground or polished parts and surfaces.

CautioN!


Steering Knuckle Bushing Removal

Remove the retaining ring for the grease cap in the upper and lower steering knuckle halves. Discard the retaining rings. Leave the grease caps in place. This will help drive the kingpin bushing from the steering knuckles during the next step.

Place the upper steering knuckle in the press. Be sure to support the upper steering knuckle so it sits in-line with the steering arm receiver and the press’s ram. Position the bushing driver and press the grease cap, bushing, and seal from the steering knuckle. Discard the bushing and seal.

Repeat this procedure to remove the kingpin bushing from the lower steering knuckle. However, this steering knuckle is placed upside-down in the press to remove the bushing.

Remove the O-rings from the grease caps and discard them.

Steering Knuckle Bore Measurement

Clean the bushing bore and then use an inside micrometer or a telescoping

Before applying hydraulic pressure to remove or install the kingpin bushing, properly support the upper steering knuckle.

CautioN!

Before applying hydraulic pressure to any tooling set-up, always make sure the press plate, adapters and components being pressed are properly positioned.

WarNiNg!

Refer to the Quick Reference Guide for details on the bushing driver and steering arm receiver tools.

Note


gauge to measure the steering knuckle’s bore.

Measure the bore of the upper steering knuckle at each end, in two locations and 90 degrees apart. If the average measurement is more than the steering knuckle bore maximum diameter specification, as found on ISIS®, replace the steering knuckle.

Repeat this procedure for the lower steering knuckle.

Steering Knuckle Bushing Installation

Place the upper steering knuckle in the press with the machined side up. Install the kingpin bushing from the axle side of the steering knuckle. Using the bushing driver tool, press the bushing into the upper steering knuckle. Refer to ISIS® for the bushing depth specification. Repeat this procedure for the lower steering knuckle.

After installing both the upper and lower bushings, size them using the adjustable straight flute reamer to ensure the kingpin fits properly.

Refer to the Quick Reference Guide for details on the bushing driver tool.

Note

Before applying hydraulic pressure to any tooling set-up, always make sure the press plate, adapters and components being pressed are properly positioned.

WarNiNg!


Steering Knuckle Bushing Reaming

Place the upper steering knuckle in a vise with brass jaws or rubber face caps.

Install the reamer into the steering knuckle until the blades touch the kingpin bushing.

Rotate the reamer smoothly with light, downward pressure.

Slide the reamer out through the bottom of the steering knuckle. If the reamer can only be removed from the top, rotate it in the opposite direction used to cut the bushing.

Clean and remove all bushing material from the steering knuckle. Be sure to remove any material from the grease channels and dimples. Install the upper steering knuckle on the kingpin.

Check for proper fit by rotating the steering knuckle to verify there is no binding on the kingpin. Refer to ISIS® for the proper clearance between the bushing and kingpin. If the bushing is

Do NOT hone or burnish the kingpin bushings. Ream the kingpin bushings using an adjustable straight flute reamer.

CautioN!

Be sure to protect the steering knuckle components by using a vise with brass jaws or rubber face caps.

CautioN!

Refer to the Quick Reference Guide for details on the adjustable straight flute reamer.

Note


too tight, repeat the reaming procedure until proper clearance is achieved.


Kingpin Seal Installation

Place the upper steering knuckle in a vise with brass jaws or rubber face caps, with the machined surface of the steering knuckle facing up.

Place the kingpin seal into the bore of the steering knuckle. The seal lip should face out, or toward the axle.

Using the same bushing driver tool as previously shown for pressing in the bushings, drive the seal firmly into the steering knuckle until it makes contact with the bushing.


Clean the brake backing plate bolts with a wire wheel. Then, use a tap to clean the threads of the bolt holes in the upper steering knuckle. Flush the assembly with brake cleaner and dry with compressed air.

Before installation, be sure all Loctite® has been removed from the mounting bolts and thread bores in the upper steering knuckles. Apply new Loctite® to ensure the bolts are properly tightened.

CautioN!


Steering Knuckle Reassembly

Install a new thrust bearing on the lower kingpin with the seal facing up, toward the axle. Install the shim on the upper kingpin.

Pack the bushing dimples and grooves on the upper and lower steering knuckles with multipurpose lithium grease. Install the upper steering knuckle on the upper arm kingpin.

Install the lower steering knuckle on the lower kingpin and install the two cap screws hand tight.

Using a bottle jack, slightly raise the lower steering knuckle and thread three of the spider bolts for alignment. Tighten only the two cap screws to the specification found on ISIS®.

Lower the bottle jack enough that all the vertical clearance is under the axle.

Attach a magnetic base dial indicator to the axle and place the tip of the indicator on top of the steering knuckle. Zero the indicator.

Raise the bottle jack until there is no clearance between the steering knuckle


and the bottom of the axle. The axle should be slightly raised.

Compare the reading on the dial indicator with the specification found on ISIS®. If the reading does not meet the specification, loosen the cap screws and move the steering knuckle up or down until the proper clearance is reached. If necessary, use a shim.

Remove one of the cap screws. Install a new cap screw and tighten to the specification found on ISIS®. Repeat this step for the other cap screw.

Recheck the vertical clearance with the dial indicator. Remove the brake spider bolts. Remove the bottle jack and assemble the wheel ends.

If the drag link was removed, install it on the steering arm. Tighten the castle nut to the specification found on ISIS®. If necessary, turn the nut to the next castle slot and insert a new cotter pin.

Install the tie rod end into the lower steering knuckle arm. Tighten the castle nuts to the specification found on ISIS®. If necessary, turn the nut to the next castle slot and insert a new cotter pin.

Lubricate the new O-rings and install them on the grease caps. Install the upper grease cap with a new retaining

Remove excess grease from the upper and lower steering knuckle bores before installing the grease caps.

Note

ring. Repeat this procedure for the lower steering knuckle.

Follow the proper procedures, to reinstall the brake components on the steering knuckle, which includes the application of Loctite® on the brake spider bolts. Then install the hub assembly and wheel.

Raise the vehicle and remove the jack stands and jack. Grease the steering knuckles with the vehicle on the floor.


NOTES


Conclusion 33

Conclusion

This concludes the International® ProStar® Front Air Suspension and Axle Assembly program. Completion of this educational process is a key component towards International Technician Certification. You are now required to take a post-test.

NOTES


study guide international p s international pros series

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