

Titan part 779-138 is a caster lock pin used to secure the locking mechanism on compatible PowrLiner airless striper front or rear casters. This pin engages the caster brake to prevent unwanted machine movement during line striping operations. A worn, bent, or missing lock pin can cause the caster to unlock unexpectedly, leading to machine drift, uneven stripes, or safety hazards. Replacing with an OEM pin restores positive caster locking and stability.
| Part Number | 779-138 |
|---|---|
| Part Description | Caster Lock Pin |
| Brand | Titan |
| Fits |
PowrLiner 8900, 8900 XLT, 8900 XLT SP, 6950, 6900XLT, 6900XLT SP, 4950, 4900, 4900XLT |
| Condition | New |
The Titan 779-138 Caster Lock Pin is a genuine OEM replacement pin that engages the caster brake mechanism on compatible PowrLiner airless striping machines. When the caster lock pedal is pressed, this pin slides into a detent or through a hole in the caster swivel to prevent rotation, keeping the machine steady during striping operations.
Over time, lock pins can become bent from impact, wear at the engagement point, or become lost if retaining clips fail. A damaged or missing lock pin allows the caster to swivel unexpectedly, causing the machine to drift offline, produce wavy stripes, or roll away on slopes. Replacing the pin restores positive locking and operator confidence.
| Locks caster swivel | Prevents front/rear caster from pivoting |
|---|---|
| Holds machine straight | Maintains direction during stripe application |
| Safety | Prevents unintended rolling on inclines |
| Engages with pedal | Transfers foot pedal force to caster brake |
| Caster will not lock | Lock pedal moves but caster still swivels |
|---|---|
| Pin is bent | Visible deformation preventing full engagement |
| Pin is missing | Retaining clip failed or pin fell out |
| Excessive wear | Grooves or flat spots on pin engagement area |
Titan part 779-138 is a direct replacement caster lock pin for the following PowrLiner models. Always verify with your machine’s parts diagram for exact fitment.
| Model | Component |
|---|---|
| PowrLiner 8900 | Caster lock pin |
| PowrLiner 8900 XLT | Caster lock pin |
| PowrLiner 8900 XLT SP | Caster lock pin |
| PowrLiner 6950 | Caster lock pin |
| PowrLiner 6900XLT | Caster lock pin |
| PowrLiner 6900XLT SP | Caster lock pin |
| PowrLiner 4950 | Caster lock pin |
| PowrLiner 4900 | Caster lock pin |
| PowrLiner 4900XLT | Caster lock pin |
When replacing the caster lock pin, inspect these associated components for complete repair.
The small clip that holds the pin in place; often lost or broken at the same time.
Check for bent rods or loose connections that prevent full pin engagement.
Inspect caster for worn bearings or swivel damage that could affect locking.