Check your clutch bearings, springs etc, transmittor settings/trims,linkages,needles.
Is it moving as soon as your start it up or is it running ok and suddenly surges?

The hellfire has a poor turning radius, i think 1 direction turns better than the other. At truggyracers.com there is a large forum on the hellfire and the steering problem is discussed alot. Go back a fair way in the hellfire forum and you will find some possible remedies to the steering issue.
I had to grind a bit off the right side steering servo post as the the servo saver arms were hitting the post and i was unable to get full turn.
You do need a strong steering servo, at least 200 oz,also you need correct diff oils to help you turn, 5/10/3 or 5/7/3 is a good starting point.
Make sure your servo saver nut is fairly tight on the spring or your steering will be bad.