Check the Components That Support Alignment
- Recognize suspension defects that undermine alignment.
- Separate trailer support from axle support during service.
- Match bearing service and replacement wheels to the installed equipment.
- Inspection light — Illuminate spring eyes, bolt holes, springs, and suspension attachment points.
- Wheel chocks — Help prevent rolling while positioning and supporting the trailer.
- Rated jack and support stands — Lift and support the trailer at manufacturer-approved locations; support affected axles separately before suspension disassembly.
- Pry bar — Gently check accessible suspension joints for looseness after the trailer is safely supported.
- Torque wrench and sockets — Check attachment fasteners using the applicable manufacturer's tightening instructions.
- Dial indicator — Measure wheel-end axial movement when required by the identified bearing arrangement's inspection procedure.
Suspension inspection includes excessive wear, elongated bolt holes, and loose fasteners. Worn spring-eye bushings and sagging or broken springs require replacement. Dexter specifies visual suspension inspection at least every 6,000 miles in this manual; intervals vary by maker.
Separate trailer support from axle support during repairs. Support the trailer according to its manufacturer's instructions on adequately rated stands, not on the axle or suspension. A block beneath the axle tube supports only the axle's weight while suspension parts are removed; on multi-axle units, support each axle before disassembling suspension components.
Bearing arrangements do not all use the same maintenance method. Conventional tapered bearings need a small amount of axial end play, while the described factory-sealed cartridge arrangement also has designed end play but requires no further lubrication. Identify the arrangement before disassembly, and do not interpret every trace of wheel-end movement as an alignment fault.
Wheel selection also matters: match bolt circle, capacity, pressure rating, rim contour, and original offset. Incorrect replacement-wheel offset can reduce axle load capacity. For the described rubber-cord torsion suspension, inspect its frame-attachment fasteners and do not weld the beam because welding heat can damage the internal cords.
How It Works
Suspension condition comes before alignment correction
Worn joints, elongated holes, and loose fasteners allow suspension locating points to shift under load, making alignment unstable. Worn spring-eye bushings and sagging or broken springs require replacement rather than an alignment adjustment that conceals the defect. Dexter specifies visual suspension inspection at least every 6,000 miles in this manual; other makers may specify different intervals.
Trailer support and axle support have different jobs
Support the trailer according to its manufacturer's instructions on adequately rated stands, never on the axle or suspension. A block beneath the axle tube supports only the axle's weight while suspension parts are removed; on multi-axle units, support each axle before suspension disassembly. This separation prevents removal of a suspension component from also removing the trailer's supporting load path.
Identify the design before judging or servicing it
Conventional tapered bearings need a small amount of axial end play, while the described factory-sealed cartridge also has designed end play but requires no further lubrication; movement alone does not establish an alignment fault. Replacement wheels must match bolt circle, capacity, pressure rating, rim contour, and original offset because incorrect offset can reduce axle load capacity. On the described rubber-cord torsion suspension, inspect frame-attachment fasteners and do not weld the beam because welding heat can damage its internal cords.
Step-by-Step Procedure
0/7 doneDexter suspension inspection interval; values vary by maker
| Visual suspension component inspection | At least every 6,000 miles |
Diagnostic Chart
| Symptom | Check | Spec / Expected | Likely cause & fix |
|---|---|---|---|
| Suspension looseness or visibly altered spring shape | Inspect spring-eye bushings, bolt holes, springs, and fasteners for wear, elongation, looseness, sagging, or breakage. | Replace worn spring-eye bushings and sagging or broken springs. Dexter visual inspection: At least every 6,000 miles; intervals vary by maker. | Wear or damage allows suspension geometry to change rather than remain securely located. Basis: LDServiceOnline |
| Wheel-end movement is found during an alignment inspection | Identify whether the assembly uses conventional tapered bearings or the described factory-sealed cartridge, then follow its corresponding inspection instructions. | Conventional tapered bearings need a small amount of axial end play; the described sealed cartridge has designed end play and requires no further lubrication. | Movement may be designed end play rather than an alignment defect; bearing condition must be judged by the correct procedure. Basis: LDServiceOnline |
| A replacement wheel fits the studs but its suitability is uncertain | Compare bolt circle, capacity, pressure rating, rim contour, and offset with the required wheel configuration. | Match all listed compatibility characteristics, including original offset. | Stud fit alone does not establish compatibility; incorrect offset can reduce axle load capacity. Basis: LDServiceOnline |
| Loose frame attachments or a proposed welded repair on a rubber-cord torsion beam | Inspect frame-attachment fasteners and identify the suspension design before selecting a repair method. | Inspect the described torsion suspension's attachment fasteners; do not weld its rubber-cord beam. | Loose attachments compromise secure mounting, and welding heat can damage the internal rubber cords. Basis: LDServiceOnline |
At the Bay: Diagnose the Case
CASE 1 / 4
Suspension looseness or visibly altered spring shape
- Test
- Compare
- Correct
Select the next check
Basis: LDServiceOnline. A likely cause is a hypothesis; confirm it with the applicable service procedure before repair.
Common Bay Mistakes
- ✕ Using the axle or suspension to support the trailer's weight.
- ✕ Removing suspension parts before supporting each affected axle separately.
- ✕ Treating all wheel-end movement as a fault or applying the same service method to every bearing.
- ✕ Approving a wheel by stud fit alone or welding a rubber-cord torsion beam.
Quick Check
Practice only — not scored.
Plan the Service Sequence
Planning practice only. Follow the applicable manufacturer's instructions, employer safety program and qualified supervision on real equipment.
Plan the first action. Compare the service steps with the bay mistakes.
Source: LDServiceOnline — 49, 66-71