What drive size on a ratchet can be used to release the tensioner pulley 1999 ford F-150 truck?

You won't use a ratchet drive size to *release* the tensioner pulley on a 1999 Ford F-150. You'll use a ratchet *with a specific socket* to turn the tensioner *bolt* which *releases* the tension on the belt, allowing you to remove or replace the pulley.

The size of the socket needed will depend on the specific tensioner design on your particular 1999 F-150's engine (4.2L, 4.6L, or 5.4L). It's usually a 13mm or 15mm socket, but you MUST verify this yourself by looking at your truck's tensioner. Using the wrong size could strip the bolt or damage the tensioner.

Before you start: Consult a repair manual specific to your F-150's engine for the exact procedure and correct socket size. This is crucial to avoid damage and ensure you do the job safely and correctly. Improperly releasing the tensioner can lead to belt damage or injury.