Separate Slip-On Rotor Work from Hub-and-Rotor Removal
- Distinguish slip-on rotor service from hub-and-rotor removal.
- Protect hydraulic connections and complete required bearing work.
- Apply the correct fastener specifications and verify final clearance.
- Jack, rated jack stands, and wheel chocks — Lift, support, and secure the trailer before wheel removal; do not rely on the jack alone.
- Socket and wrench set — Remove and reinstall wheel, caliper, line-support, and applicable wheel-end hardware.
- Torque wrenches — Tighten covered caliper mounting bolts to 25–35 ft-lb and specified line-clamp bolts to 85–100 in-lb; use the applicable maker's procedures for other fasteners.
- Caliper hanger — Support the displaced caliper independently of its hose while preserving the hydraulic connection.
- Bearing-cap removal tool and soft-faced mallet — Remove the cap and seat the replacement cap with controlled force during hub-and-rotor service.
- Inspection light — Inspect rotor seating, hose routing, line supports, and rotating-component clearance.
The source distinguishes a rotor that fits onto the hub face from a hub-and-rotor assembly removed from the spindle. These are different service paths. Both begin with safe trailer support, wheel removal, disabled actuation, no hydraulic pressure, and free rotor rotation.
For rotor-only service, move the caliper assembly aside without disconnecting its hose or allowing air into the hydraulic system. Release applicable line-support clamps before moving the assembly, and do not suspend it from the hose. The replacement rotor fits flush against the hub face.
For hub-and-rotor service, the source additionally removes the cap, spindle nut, and outer bearing before withdrawing the assembly. Reinstallation includes the outer bearing, washer, spindle nut adjustment under the applicable bearing procedure, the nut retainer, and a new cap with its rubber plug. Do not substitute the simpler rotor-only procedure for these wheel-end tasks.
Dexter specifies 25–35 ft-lb for caliper mounting bolts in the covered 6K/8K rotor and 7K hub-and-rotor procedures and 85–100 in-lb for the specified line-clamp bolts; values vary by maker. Finish by checking rotor-to-line clearance, reconnecting actuation, mounting the wheel correctly, and checking wheel clearance from the line and caliper.
How It Works
Identify the assembly before choosing the removal path
A slip-on rotor separates from the hub face, while a hub-and-rotor assembly is withdrawn from the spindle after removal of the cap, spindle nut, and outer bearing. Both paths require safe trailer support, wheel removal, disabled actuation, no hydraulic pressure, and free rotor rotation before proceeding. Choosing the correct path prevents unnecessary wheel-end disturbance or omission of required bearing work.
Preserve hydraulic integrity and rotor seating
Release applicable line-support clamps before moving the caliper, keep its hose connected, and support the assembly without loading the hose. Hose loading can damage the hose or its fittings, while opening the circuit can introduce compressible air that compromises hydraulic response. A replacement slip-on rotor must sit flush against the hub face because uneven seating can make the rotor run unevenly through the caliper.
Restore the wheel end and verify clearance
After hub removal, reinstall the outer bearing, washer, and spindle nut, perform adjustment under the applicable bearing procedure, and fit the nut retainer and a new cap with its rubber plug. Dexter specifies 25–35 ft-lb for caliper mounting bolts in the covered 6K/8K rotor and 7K hub-and-rotor procedures and 85–100 in-lb for the specified line-clamp bolts; these values are not universal. Check rotor-to-line clearance by spinning the rotor, reconnect actuation, then mount the wheel under its torque procedure and spin it to check clearance from the line and caliper.
Step-by-Step Procedure
0/8 doneDexter covered rotor-service values; values vary by maker
| Caliper mounting bolts | 25–35 ft-lb |
| Specified line-clamp bolt | 85–100 in-lb |
Diagnostic Chart
| Symptom | Check | Spec / Expected | Likely cause & fix |
|---|---|---|---|
| The rotor does not separate from the hub as expected. | Confirm whether the rotor fits onto the hub face or forms an assembly removed from the spindle before applying further removal force. | Hub-and-rotor removal requires the documented cap, spindle nut, and outer-bearing removal path. | The rotor-only procedure may have been selected for a hub-and-rotor assembly. Basis: LDServiceOnline |
| The hose becomes taut when the caliper is moved aside. | Stop moving the caliper, verify that applicable line-support clamps are released, and support the caliper independently of the hose. | Keep the hose connected and do not suspend the caliper from it. | A retained line support or unsupported caliper is placing load on the hose. Basis: LDServiceOnline |
| The replacement slip-on rotor does not sit flush against the hub. | Inspect the mating surfaces for debris, corrosion buildup, burrs, or damage, and verify that the replacement part matches the assembly. | Do not proceed with uneven seating; correct the obstruction or part mismatch before reassembly. | Contaminated or damaged mating surfaces, or an incorrect replacement part, can prevent proper seating. Basis: General shop practice |
| The rotor or wheel contacts the hydraulic line after reassembly. | Inspect line routing and support placement, check rotor-to-line clearance, then check the mounted wheel's clearance from the line and caliper. | For the covered Dexter procedures, caliper mounting bolts: 25–35 ft-lb; specified line-clamp bolts: 85–100 in-lb. Verify clearance by rotation. | The line or its supports may have been repositioned incorrectly during service. Basis: LDServiceOnline |
At the Bay: Diagnose the Case
CASE 1 / 4
The rotor does not separate from the hub as expected.
- 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
- ✕ Treating hub-and-rotor removal as a simple slip-on rotor change.
- ✕ Opening the hose or hanging the caliper from it for convenience.
- ✕ Skipping the applicable bearing adjustment after hub removal.
- ✕ Applying Dexter values universally or omitting final clearance checks.
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.
Hands-on: Test Bench Practice
Symptom: Healthy trailer. Learn what good readings look like.
Tap a point to place the red probe.
Good system: ~12.6 V at pins, 3.2 Ω across a 12×2-inch magnet (unplugged), 3.0 A per magnet at 12 V full gain, and at least 10.5 V at the magnet — the chart values from the axle manuals.
Hands-on: Shop Test Equipment
Hydraulic Pressure & Relief Gauge
0–5,000 psi gauge on the pump pressure port, DC clamp meter, battery voltmeter
🛠 Equip your bay for this test →Symptom: Routine check before a customer pickup.
Spec limits used
- 3,200 psi — Primary relief (factory preset) (KTI Hydraulics Troubleshooting Manual 2019)
- 1,500 psi — Secondary relief, circuit 111 (KTI Hydraulics Troubleshooting Manual 2019)
- below 9 V — Low-voltage alarm (KTI remote)
- illustrative only — Motor current & voltage drop (General shop practice)
Simulated readings for practice. Always follow the manufacturer's procedure and values on a real trailer.
Source: LDServiceOnline — 37-40