Recall 21V660 affects 114 2016-2021 Thomas Built Buses Saf-T-Liner Hdx buses for power-steering-hose routing. Repair is free at any franchised Thomas Built Buses dealer.
Thomas Built Buses is recalling 114 2016-2021 Saf-T-Liner Hdx transit buses because the power steering hose can sit too close to power cables. Damage to the hose can cause a leak and increase the risk of a fire; Thomas Built Buses dealers will complete the free repair.
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What's wrong?
The power steering hose on 2016-2021 Thomas Built Buses Saf-T-Liner Hdx buses carries hydraulic fluid for the steering assist system. That fluid helps the steering gear move when the driver turns the wheel, so the driver is not doing the full steering work by hand. The hose needs a clear path away from heat, sharp edges, and electrical cables.
On affected buses with an ISL or L9 engine, the hose can be routed too close to the power cables. Contact between the hose and a power cable can rub or heat-damage the hose insulation and hose wall. Once the hose is damaged, power steering fluid can leak near electrical power cables, which is the condition Thomas Built Buses traced during its investigation.
There is no warning sign before failure. Drivers or maintenance staff should treat any new steering-assist change, fluid smell, visible fluid, or hose contact near the power cables as a reason to take the bus out of service for inspection.
Who's affected?
Spans six model years (2016-2021), all tied to the same power steering system component.
| 2019 Thomas Built Buses Saf-T-Liner Hdx | power steering system |
|---|---|
| 2020 Thomas Built Buses Saf-T-Liner Hdx | power steering system |
| 2016 Thomas Built Buses Saf-T-Liner Hdx | power steering system |
| 2018 Thomas Built Buses Saf-T-Liner Hdx | power steering system |
| 2021 Thomas Built Buses Saf-T-Liner Hdx | power steering system |
| 2017 Thomas Built Buses Saf-T-Liner Hdx | power steering system |
| Units affected | 114 |
| Field incidents | NHTSA has logged 1 field incident to date. |
The year and model narrow the scope, but the VIN decides. Check your VIN to confirm whether your specific bus is included.
What's the safety risk?
A damaged power steering hose can leak and increase the risk of a fire. Because the issue is tied to hose routing, confirm whether your VIN is included and schedule the dealer inspection promptly. Repair is free at any franchised Thomas Built Buses dealer.
What should I do?
- Check your VIN to confirm your 2016-2021 Thomas Built Buses Saf-T-Liner Hdx is included in this recall.
- Contact a franchised Thomas Built Buses dealer to schedule the free power steering hose routing inspection and repair.
- Bring the owner letter if you have it. If not, reference recall number 21V660 when you call.
- Drive only as needed until the dealer inspects the hose routing, since hose damage can cause a leak and increase fire risk.
What happens at the repair
At the dealer, a Thomas Built Buses technician inspects how the power steering hose is routed near the power cables. If the hose does not have enough clearance, the technician changes the routing so the hose is kept away from the cables and is less exposed to damage. Parts and labor are covered now at a Thomas Built Buses authorized service facility. Ask the service desk to confirm that the hose inspection and routing modification are listed on the repair order.
Timeline
| August 25, 2021 | NHTSA published the recall |
|---|---|
| October 15, 2021 | Owner notification mailed |
| October 17, 2021 | Dealer notification began |
| October 17, 2021 | Dealer notification ended |
| October 17, 2021 | VIN-searchable in NHTSA's database — Check your VIN to see whether this recall applies to your specific vehicle. |
| October 17, 2021 | Interim owner notification (was planned for this date) |
Frequently asked questions
What is recall 21V660?
Recall 21V660 covers 114 2016-2021 Thomas Built Buses Saf-T-Liner Hdx transit buses equipped with an ISL or L9 engine. The power steering hose routing leaves inadequate clearance from power cables, which can damage the hose, cause a leak, and increase fire risk.
What should I do if my 2016-2021 Thomas Built Buses Saf-T-Liner Hdx is on this recall?
Check your VIN to confirm your specific bus is included in recall 21V660. If it is, contact a franchised Thomas Built Buses dealer or DTNA customer service at 1-800-547-0712 and reference recall 21V660 or DTNA recall FL898. The dealer inspection and routing modification are free.
Is the recall repair free?
Yes. Federal recall law requires the manufacturer to repair the defect at no cost. DTNA will inspect the power steering hose routing and modify it as necessary free of charge at a franchised Thomas Built Buses service location.
What is the safety risk?
The safety risk is fire. If the power steering hose is damaged by contact with nearby power cables, the hose can leak and increase the risk of a fire. The repair path is to confirm the VIN, then have the dealer inspect and correct the hose routing.
When were owners notified about recall 21V660?
DTNA mailed owner notification letters on October 17, 2021. If you own or operate one of these buses and never received a letter, check your VIN and call a franchised Thomas Built Buses dealer with recall number 21V660 or DTNA recall FL898.
More information
| NHTSA campaign page | nhtsa.gov/vehicle-recalls/21V660000 |
|---|---|
| Thomas Built Buses customer service | 1-800-547-0712 |
| NHTSA recall # | 21V660 |
| NHTSA recall # (full) | 21V660000 |
Source documents
-
Download Recall Document (PDF) (PDF) - Download Quarterly Report (PDF)
- Download Owner Notice (PDF)
- Download Misc. Document (PDF)
- Download Owner Notification Letter (PDF)
- Download Recall Report (PDF)
- Download Recall Acknowledgement (PDF)
This article is generated from NHTSA's primary recall filings and reviewed against the source on May 20, 2026. RecallNotify does not paraphrase NHTSA's consequence language; that text is reproduced as written above. Editorial standards →