14TCH

4x2

TerraStar

3.0 ± 0.125 or 3 ± 1/8

14TCP, 14TCR

4x2

AE Bus

3.0 ± 0.125 or 3 ± 1/8

All dimensions are in inches

6. Once the proper ride height is set, and air bags are inflated with 120 psi, measure each corner of the vehicle as shown
in Figures 4‐7 and record measurements.
◦ The front tires MUST be pointed straight forward to prevent any influence to the lean from King Pin Inclination.
◦ Measure the front suspension at the spring shackle bolt as shown in Figures 4 and 5. Mark the bolt with a paint
pen so you have a reference point for future measurements that may be required.
◦ Measure the rear of the vehicle at the aft frame flange (bottom of the flange) as shown in Figures 6 and 7.
Location may vary slightly by application.
◦ If the lean is less than or equal to 3/8” Front and/or Rear, the vehicle is in spec. The repair is not warrantable.
◦ You can still advise on what repair would correct the lean, but at customer pay.
7. Dump the air from the suspension and verify the frame stop is touching the axle U‐bolt on both sides of the truck. The
frame stop may not touch the U‐bolt on all vehicles. The space between the frame stop and U‐bolt should be even from
the right to left side for those applications.
◦ Remeasure from the same locations used in Step 6 and record (Measurements are taken with suspension
dumped).
◦ This will help show if the rear suspension is contributing to the lean (Especially 4x2 chassis), or help confirm a
frame issue as the cause.
◦ Looking to see if opposite corners are still low (e.g. LF low RR low) which may help show a frame twist. Lean must
be greater than 3/8".
◦ Looking to see if the rear goes into specification with suspension dumped. This may help show the Bar Pin Height is
contributing, or show the frame is not twisted (Where a front shim may correct).
◦ If the front and rear both level out and the Bar Pin Height is not equal (Step 9) suspect an issue with a rear seat
(4x2).
Re‐inflate the air suspension before continuing
8. Use a jack and place a 1 1/2" inch block under the Front tire with the lowest reading. (Do not drive the vehicle on to the
block).

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IK1400023 ­ Suspension Lean Diagnostics

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◦ Remeasure from the bottom of the frame to ground and record.
• This will show us how the rear suspension reacts and if shimming will help to correct the issue. (If the lean is
prevalent in the front).
◦ Looking at the reaction in the rear here. (e.g. If the LF has a block, the weight transfer should cause the RR to be
lower than the measurement at #6).
◦ Use this information together with #7. Suspension reaction with a block together with suspension difference when
the suspension is dumped.
9. Measure from the center of the bar pin to the ground and record. (This step only applies to Single Rear Axle vehicles).
◦ Remove wooden block if previously installed.
◦ You must remove the Spring Eye Bushing mounting bolts.
◦ Using a frame jack at the rear of the vehicle, raise the frame evenly until the Bar Pin clears the Mounting Bracket
on both sides.
• The rear tires should still be on the ground during this procedure. Only lift the rear of the frame until the Bar
Pin clears the mounting bracket.
• This will help determine if there is an issue with a rear seat or rear seat mounting.
◦ See Figure 8 below.
◦ Do not perform this step on 6x4 configurations.
◦ If the Pin Bar Height is greater than 7/16” difference the repair will require changing a seat out on one side.
◦ If the Pin Bar Height is 7/16” or less shimming the front suspension (steer axle) will be required to correct the lean.
◦ You will need to watch what the result is in #8 closely when this measurement is off.
Figure 9

10. Record the axle seats degrees or part number on the physical part if possible. See Figure 10 and Figure 11 below.
◦ If a seat change is required to correct the lean, only change 1 seat size. (Only 1 seat will be replaced).
◦ The seat that needs to be changed is the Pin Bar measurement that is smaller. (Only 1 seat will be replaced).
◦ The change should increase the Pin Bar height on the Low Side.
◦ If the seat is changed, make sure the correct Seat Plate is installed or changed if needed.

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IK1400023 ­ Suspension Lean Diagnostics

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◦ If the thicker side of the seat is facing forward (towards the steer axle) choose a seat one size smaller.
◦ If the thicker side of the seat is facing rearward (away from the steer axle) choose a seat one size larger.
Figure 10

Figure 11

11. Take 4 photos of the unit. Please ensure the photos clearly show the lean. (Only perform this step if a case file is
needed).
◦ Front, Rear, Left Side, Right Side.
◦ For documentation purposes. This will help show any potential offset loading (A/C system in a commercial bus,
hydraulic tank, etc..) and the severity of the observed lean.
◦ This is especially true if you have a case file with a front suspension less than or equal to 8000 lbs and shimming
did not resolve the issue.
Seat Parts Information

Pinion Angle
Loaded

Plate Parts Information

Machined
Cast
Cast Pinion Angle
4x2 HD Plate
Part Number Part Number (As listed in parts catalog)

2

4x2 MD Plate
(with Shock Mount)
Left Side

Right Side

0.60

3601570C2 3548295C1

3541719C3 3541725C3 3541726C3

2.26

3601571C2

2.50

3601572C2 3548296C1

2.75

3601573C2

3541720C3 3541727C3 3541728C3

3.23

3601574C2

3541720C3 3541727C3 3541728C3

3.47

3601575C2

3541721C3 3541729C3 3541730C3

4.45

3601576C2 3548297C1

5.42

3601577C2

8.33

3601579C2 3548298C1

9.55

3601581C2

10.28

3601583C2 3548299C1

10.52

3601584C2

3541723C3

11.49

3601585C2

3541724C3

12.20

3601586C2 3548300C1

12.46

3601587C2

3541720C3 3541727C3 3541728C3
4

6

3541720C3 3541727C3 3541728C3

3541721C3 3541729C3 3541730C3
3541721C3 3541729C3 3541730C3

10

3541722C3
3541723C3

12

14

3541723C3

3541724C3
3541724C3

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IK1400023 ­ Suspension Lean Diagnostics

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( Back to Top )

Other Air Suspension
1. Check front axle suspension weight rating.
◦ For any lean issues with a front suspension rating of 8,000 LBS or less please refer to IK0300061 ‐ 8,000 LBS Front
Suspension Lean Correction.
2. Check the unit for any offset loading.
◦ Note any items that may cause offset loading.
3. Inspect the suspension for any third party (bodybuilder) installed components such as stabilizer bars.
◦ International does not install stabilizer bars on most suspensions.
◦ Exceptions: BE Buses, Front suspension on CityStars, and the Multi‐Link front air suspension (These will have
stabilizer bars).
4. Check the tire pressure for all tires.
◦ Adjust pressures if needed.
◦ Record current tire pressures.
5. Verify the ride height is set properly.
◦ Follow the manufacturer's recommended ride height setting for the suspension installed.
◦ Hendrickson suspension website.
6. Measure each corner of the vehicle as shown in Figures 4‐7 and record measurements.
a. The front tires MUST be pointed straight forward to prevent any influence to the lean from King Pin Inclination.
b. Measure the front suspension at the spring shackle bolt as shown in Figures 4 and 5. Mark the bolt with a paint
pen so you have a reference point for future measurements that may be required.
c. Measure the rear of the vehicle at the aft frame flange (bottom of the flange) as shown in Figures 6 and 7.
Location may vary slightly by application.
7. Dump the air from the suspension and verify the frame stop is touching the axle U‐bolt on both sides of the truck. The
frame stop may not touch the U‐bolt on all vehicles. The space between the frame stop and U‐bolt should be even from
the right to left side for those applications.
◦ Remeasure from the same locations used in Step 6 and record (Measurements are taken with suspension
dumped).
8. Take 4 photos of the unit. Please ensure the photos clearly show the lean. (Only perform this step if a case file is
needed).
◦ Front, Rear, Left Side, Right Side.
( Back to Top )

Vari‐Rate Spring Suspension
1. Check front axle suspension weight rating.
◦ For any lean issues with a front suspension rating of 8,000 LBS or less please refer to IK0300061 ‐ 8,000 LBS Front
Suspension Lean Correction.
2. Check the unit for any offset loading.
◦ Note any items that may cause offset loading.
3. Inspect the suspension for any third party (bodybuilder) installed components such as stabilizer bars.
◦ International does not install stabilizer bars on most suspensions.

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IK1400023 ­ Suspension Lean Diagnostics

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◦ Exceptions: BE Buses, Front suspension on CityStars, and the Multi‐Link front air suspension (These will have
stabilizer bars).
4. Check the tire pressure for all tires.
◦ Adjust pressures if needed.
◦ Record current tire pressures.
5. Measure each corner of the vehicle as shown in Figures 4‐7 and record measurements.
a. The front tires MUST be pointed straight forward to prevent any influence to the lean from King Pin Inclination.
b. Measure the front suspension at the spring shackle bolt as shown in Figures 4 and 5. Mark the bolt with a paint
pen so you have a reference point for future measurements that may be required.
c. Measure the rear of the vehicle at the aft frame flange (bottom of the flange) as shown in Figures 6 and 7.
Location may vary slightly by application.
6. Take 4 photos of the unit. Please ensure the photos clearly show the lean. (Only perform this step if a case file is
needed).
◦ Front, Rear, Left Side, Right Side.
( Back to Top )

Measuring Spring Height
Below is the procedure to measure the most commonly replaced leaf springs on International trucks. If a leaf spring is in
question for sagging, a lean, or a collapsed condition, then before the spring is replaced it should be measured. If the
measurements taken on the spring are within the specifications shown below, then the spring is not causing the lean
complaint or is not defective.
NOTE:
• It is common for springs to be flat or have a negative arch when loaded.
◦ The springs are designed this way, and it is all based on the spring rate.

Measurement Technique
The measurements below are with the spring in a free, unloaded state. This is known as free camber. To make these
measurements, the spring must be removed from the vehicle. Use a piece of straight metal or a line, and place it between
the centers of the 2 eyelets. Use a square to measure 90 degrees of the center of the top of the spring to the center line.

Dual Eye Leaf Spring Measurements

Part Number

Unloaded Height
(Inches)

Tolerance Range
(Inches)

3806666C91

4.04"

+/‐ 0.25"

6090598C93

3.14"

+/‐ 0.25"

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IK1400023 ­ Suspension Lean Diagnostics

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6090598C92

3.14"

+/‐ 0.25"

3610111C3

5.29"

+/‐ 0.25"

3869789C92

2.72"

+/‐ 0.25"

3533197C91

3.89"

+/‐ 0.25"

6112882C91

2.8"

+/‐ 0.25"

2040041C92

3.55"

+/‐ 0.25"

3533196C91

3.55"

+/‐ 0.25"

3806667C91

3.49"

+/‐ 0.25"

3533198C91

3.97"

+/‐ 0.25"

3540221C91

3.08"

+/‐ 0.25"

Spring End to Spring End Measurements

Part Number

Unloaded Height
(Inches)

Tolerance Range
(Inches)

3534532C92

6.25"

+/‐ 0.25"

3534537C91

6.25"

+/‐ 0.25"

( Back to Top )

Other Resources
• Master Service Information Page
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