Look for a tube hanging loose. It should connect there. If you put fluid in it will drip on the ground.
Looks like someone tried a repair.

 

That may be where the feed line plugs into the brake master cylinder reservoir.

 

ok, thanks so much but, that line is flexible go through under the fuse box from the transmission is like go connected to the wall in the car behind the wheel, I took the picture like that but is not in that address. so any diagram will be goodd to see or if somebody has HHR 2006 and is willing to check on it will be great also.
thanks

 

Some pictures in this thread

https://www.chevyhhr.net/forums/prob...ylinder-63980/

 

That doesn't penetrate the firewall, only the master cylinder does that, and it has a rod on it that connects to the clutch pedal.

That has an O-ring, and should plug into the brake master cylinder. If it is indeed part of the problem. Look for a hole that's the same size.

But donbrew is right, that looks like a shoddy repair. Whatever it turns out to be, should be replaced with new.

 

so have to replace all master cylinder including this part o-ring? , if was a shoddy repair before I bought this car because I never repair that part...

 

Looks like Oldblue got it. #4, hard to tell which end.
GM part number
24231368

 

thanks RJ_RS_SS_350 and oldblue for your help, yes is the number 4, 3 and 14,(all together that is the part that was disconnected in my HHR) so I have to replace the number 4, 3 and 14 (all) connecting to firewall?.where can I find the part name?, thanks so much guys !!!

 

Here is a screenshot from CarID. Definitely looks like the lower end. Should just be #4 that you need. And bleed the clutch. I don't know if you need to bleed the brakes, they share the reservoir.

EDIT: On another look, seems to be the top of the hose.

 

Thanks so much I found in rockauto, the name is clutch Hydraulic Hose, but one of the side came from transmission, right?
https://www.rockauto.com/en/moreinfo...=2332&jsn=1104