Heater Control Valve Cable Screw

[tartan18]

This will sound like an odd request but could someone tell me the size of the small screw that clamps the heater control cable to the heater valve. My cable was sliding through the clamp and when I tried to tighten it down I've managed to round off the head of the screw. I want to avoid pulling the valve out if I don't have to so knowing in advance the size of the screw would be a great help. Thanks.

[azruss]

by your picture, the screw is not factory. This means the hole has been changed and will have to match it to whatever will work.

[tartan18]

I neglected to mention that I have replaced the stock heater value with a new one I got from Auto Ricambi. Finally figured out that the control valve cable clamping screw is a M4-.70