when the brake pedal is depressed the abs pump is making a pinging/grinding sound for a few seconds.. is quiet.. than comes right back again. tried pulling the abs fuse and it still continues to do this.

I pulled the fuseable link on the positive side of the battery terminal with the picture of (!) around it. not too sure what this does but it makes it go away, but than the pedal is hard as a rock and only the front brakes work.

what causes this to do this?

hope what i explained makes since to somebody on here
all help appreciated
thanks,
andrew

 

Have you checked the brake booster accumulator?