I am a huge advocate of this and have been preaching this for years. Not only do videos give you credibility, but it gives the consumer the ability to compare what "Good" vs "Worn/Bad" brake pads (or whatever items) look like. Seeing is believing. This helps immensely and puts the consumer at ease, making the process seamless.  

I use video all the time for clients and it plain works....and not just for cars...for anything.
It helps from the customer point of view but there is also a fundamental marketing benefit...creating Youtube videos that are properly titled, described and tagged creates visibility within Google.  Get Google to like you and your site will show up for important search terms that bring in customers.  I do it ALL the time.

The simple way

1) create a video --it doesn't have to be Oscar quality.  

2) Post it to your Youtube channel - use a good title, description and tags.

3) Copy the url from Youtube.

4) Share it in emails to your email list.

There are a couple of refinements but that is essentially it.

Thanks John.