How to fix a broken recovery partition (remove it) when repairing it is not possible? My main system is bootable but disk utility says it needs to be repaired.

I can start disk utility from Live-USB which can verify my OS X partition but gives errors on checking the whole disk. The error is "unknown file system" - but it appears only after it found the main file system. 

I guess my (hidden) recovery partition might be broken, since I cannot boot into it. Maybe this is the cause for disk utility to bring the error.

I would like to repair the recovery partition or at least delete it. I know there are tutorials of how to create a new one.
I removed my partition with

$ diskutil eraseVolume HFS+ Blank /dev/disk0s3


which created a blank space. 

I then also had to repair the disk in disk utility. Since then everything works fine.