My Dean bass' strings rattle when i play and i hate it. It says i need to tighten the bolt in the neck but i don't know what to use to tighten it.

Have you put strings through tuning heads and folded them back on themselves and tightened them up to standard tuning?

The best source og info would be to talk to dean customer service directly. Here's their link-
Contact Us Dean Guitars

The truss rod adjustment is on the body end of the neck, not at the headstock.
You need to;
remove the strings
unscrew the neck from the body
Make a small adjustment
Re-attach the neck
Re-string the bass
rinse and repeat until satisfied
http://support.fender.com/service_diagrams/p_bass/014-6500-323A_SISD.pdf

This sounds like a worn nut groove. The string is sitting too low. Does the buzz happen all the way up the neck or just on open string?

See if the neck is twisted at all. Might need a truss rod adjustment, or dressing on the frets.

What you are describing is normally referred to as 'high action'. There are a couple of reasons this can occur (I'm assuming that the bass is not broken in any way). Either the neck is bowed forward too much, or the bridge saddles are set too high. If you have recently changed strings to a thicker gauge then the neck bow will need to be adjusted to compensate for the increased tension. If you are not experienced it can be risky attempting to adjust the truss rod by yourself so only proceed if you are happy with the risk!

On the headstock, just behind the nut is the truss rod cover. Remove the screws and cover. Underneath will be a nut, or bolt depending on the instrument. Allen key bolts are most common, but some use a regular nut. Make sure you have exactly the right size tool before you start! With the strings at pitch, make a 1/4 turn clockwise (tightening). Retune the strings and check the action. If it has moved but not enough then try another 1/4 turn. If it has not made any difference then you may need to seek the help of a pro, as the truss rod could be broken.

Again: don't try unless you can afford to risk breaking something! If in doubt take it to your local pro guitar shop and they should be able to help.

How to Change Strings on a Dean Vendetta Guitar

Dean Vendetta is a company that makes a wide range of electric guitars. These guitars are used by famous musicians and bands such as Alice in Chains and Megadeath. If you own a Dean Vendetta guitar, you will need to change the strings periodically in order to keep your guitar sounding bright and crisp. Without changing the strings, your instrument will sound dull due to dirt and oil build-up on the strings.

Instructions

Things You'll Need:

* Dean Vendetta guitar
* String winder
* Guitar strings
* Electronic tuner
* Wire cutters


Locate the high E string. This is the string that is highest and thinnest and closest to the ground when you play the guitar.

Loosen the high E string by turning its tuning key counterclockwise. Use a string winder for this if you have one. Pull the string off of the tuning peg and out through the bridge.

Insert a new high E string through the hole in the bridge, up the neck, to the head of the guitar.

Thread the string through the hole in the tuning key so that about two inches extends beyond the hole.

Hold the string at the top end of the neck in one hand as you turn the tuning key clockwise with the other hand. A string winder makes this task much easier.

Continue to wind the string until it tightens to pitch. Use an electronic tuner to check the pitch.

Clip off the excess string with wire cutters.

Repeat these steps to install the B, G, D, A, and low E strings.


Tips & Warnings

*
Expect to re-tune often for the first few hours after installing the new strings, as they tend to stretch quite a bit at first.

Hope it helped.

Thanks for using fixya..

its a dean custom zone active bass get the parts off the dean site

If the neck of the guitar is a bolt on neck (their will be a plate holding the neck onto the body of the guitar with several screws) then this is typical. Some strings will give off small vibrations. Nothing is wrong with the guitar, usually with a string change or with time the tone will fade as the strings change to the shape.

Hope this helps,
-Aaron C.