On one side of my rear coilovers is clacking when i hit any bump or hole in the road. It only does it on one side.

H and R fully threaded coils.

 

What's the question?

 

The question is why does it make a clacking sound on every bump?

 

What does "helper spring" have to do with it?

Have you checked all of the suspension components and made sure they're all snug? Inspected all of the bushings?

I've got news for you, one noise can be one or several of dozens of things.

 

How do you know it's the coilover? And if you definitely know it's the coilover you should, by definition, know what the problem is.

 

It just makes a loud clacking sound. The previous owner said its the helper srping. Should i just remove the helper springs on both sides?

 

Why? Identify the problem and stop guessing. Get under the car and start examining everything.