Grounding & Bearing Protection
- Prevent current-related damage to wheel bearings during welding operations.
- Protect sensitive electronic modules and battery systems from weld current surges.
- Identify and shield non-metallic trailer components from spatter and heat damage.
- Ground clamp — Attach close to the weld site to ensure current does not pass through bearings.
- Hand tools — Disconnect the trailer battery and electronic modules prior to welding.
- Welding screens or blankets — Shield air springs, brake lines, and wiring from spatter and heat.
Attach the ground clamp close to the weld so current never passes through wheel bearings — arcing damages bearings.
Disconnect the trailer battery and any ABS or electronic modules before welding.
How It Works
Control the Path of Current
Weld current must be contained to a local path. If the ground clamp is poorly placed, current can travel through wheel bearings, causing arcing that damages the precision surfaces.
Isolation of Electronics
Trailer electronics, including ABS and electronic modules, are sensitive to high-voltage surges. These components, along with the battery, must be disconnected to prevent electrical failure.
Thermal Protection of Subsystems
Welding produces intense heat and molten spatter. Components such as air springs, brake lines, and wiring harnesses are susceptible to melting or degradation and require physical shielding.
Diagnostic Chart
| Symptom | Check | Spec / Expected | Likely cause & fix |
|---|---|---|---|
| Potential for current to pass through wheel bearings. | Verify the location of the ground clamp relative to the weld site. | Attach the ground clamp close to the weld. | The ground clamp is positioned such that current must travel through the axle or hubs. Basis: Hendrickson L64 Trailer Welding Procedures (Rev J) |
| Electronic module or ABS failure following welding. | Review if electronic modules were isolated before work began. | Disconnect the trailer battery and any ABS or electronic modules. | Weld current surged through the trailer's electrical architecture. Basis: Hendrickson L64 Trailer Welding Procedures (Rev J) |
| Melted or charred air springs or brake lines. | Inspect non-metallic components near the weld area for heat damage. | Per the applicable manual | Failure to shield air springs, brake lines, and wiring from spatter and heat. Basis: General shop practice |
At the Bay: Diagnose the Case
CASE 1 / 3
Potential for current to pass through wheel bearings.
- Test
- Compare
- Correct
Select the next check
Basis: Hendrickson L64 Trailer Welding Procedures (Rev J). A likely cause is a hypothesis; confirm it with the applicable service procedure before repair.
Common Bay Mistakes
- ✕ Placing the ground clamp far from the weld site.
- ✕ Allowing weld current to path through wheel bearings.
- ✕ Leaving the battery connected while welding on the frame.
- ✕ Welding near an active ABS module without disconnecting it.
- ✕ Exposing brake lines or wiring to weld spatter.
- ✕ Neglecting to shield air springs from welding heat.
Quick Check
Practice only — not scored.