Dropped end cap plate

This alert comes from National Oilwell Varco to advise customers of recent dropped end cap plate incident (P/N 2038841) and related safety precautions.

The incident

The drilled head capscrews that are used to mount the end cap plate on a Retract Dolly Wheel Assembly sheared, resulting in the end cap plate falling to the drill floor. No injuries were reported as a result of this incident. The end cap plate is typical in the following Wheel Assemblies: (P/N 2038849, P/N 2038850 and P/N 2038851). It is also used in the Dolly Roller Assembly(P/N M614004208).


Typical wheel assembly

National Oilwell Varco PS Series Top Drives utilizing a Retract Dolly System with the following Serial Numbers: PS2-165-H, PS2-194-H, PS2-199-H & PS2- 219-H.

Affected Assemblies

Retract Dolly Wheel Assemblies, (P/N 2038849), (P/N 2038850) and (P/N2038851)


Operators should visually inspect all wheel assemblies for loose/worn parts. Check for any loose, missing or unsecured fasteners on all wheel assemblies. Capscrews must be lockwired. Inspect wheel assemblies for worn surfaces, flat spots, or damaged wheels. Wheels should also be check for excessive motion or wear/flat spots indicating loose or worn bearings. If any of the above conditions are observed, contact your local National Oilwell (NOV) Service Center for assistance with disassembling and replacement of parts.

Operators should perform regular inspections and maintenance of equipment according to the service schedule. Details can be found in the Care & Operation Manuals issued with every PS Model Top Drive. Additionally, NOV recommends a thorough inspection be carried out after any jarring or other severe loading conditions are seen by the Top Drive. NOV will provide additional advice and guidance concerning this matter as it becomes available.

Other recommendations

Existing secondary retention devices/arrangements on NOV-supplied equipment may be required to be removed to perform maintenance or troubleshooting from time to time. However, part of that work should include complete reinstatement of the secondary retention devices, equipment, etc. This should be part of the job planning process and checked at the completion of any such work to verify that the devices, equipment, arrangement, etc. were reinstated in the correct manner.

Replacement of damaged and worn parts is important to rig safety and operation. Operators should also refer to previous NOV Product Information Bulletins and Safety Alerts at http://www.nov.com/drilling for additional information related to this issue and information regarding safe operation, maintenance, and inspection criteria.

Failure to follow the recommendations and/or guidance in NOV Product Bulletins may result in death, bodily injury or property damage.