Hi everyone !
Still in search for my vacuum leak causing the headlights to remain open and the brake light to light up. And I found this valve on the brake booster that is moving. Its rotating like a potentiometer and im pretty sure its not supposed to do that. Maybe thats the key for my leak ?
Looks like the booster is leaking fluid…shouldn’t be in there . Master , booster,and check valve look
Suspect.
1 Like
There’s fluid in the booster? I thought it was all vacuum…
Guess i should just change it anyway !
No brake fluid should be in the booster. If there is the master cylinder is leaking and needs replaced with the booster. It does look to have some sort of fluid build up around the master to booster mounting which is the cause of the comment. It’s worth checking either way.
I suggest one of these to track vacuum, air or boost leaks
Lisle 52700 Audio Stethoscope Amazon.com
That vacuum line should not be “Teed” either.
Headlights remaining open, brake light coming on, and loose vacuum connection at booster are unfortunately all separate and unrelated problems. And I agree it looks like you need a new booster and master cylinder too. So many projects on these cars…
Edit - I guess a leaky master cylinder actually could be the cause of the brake light coming on if it is unequally pressurizing front and rear brake lines.
Baruden,
What is causing your vacuum connection to rotate??? That stuck out in your original post… “rotating like a potentiometer”… How come? That should be pretty stable except for perhaps slight movement when the engine moves!
The T shouldn’t be there…dangerous if whatever is connected fails, then your brakes fail…
Steve
Well it was actually not fully seated in the booster so yay now its good.
The T seems to be connected to the headlights ! When pinching with pliers on to this smaller hose, the engine changes rpm.
Where can I tap some vacuum elsewhere so I can get rid of that T?
Btw, ive tried in vain to remove the master cylinder and booster but theres no way i can do it even with the valve covers off…
Sorry for the multiple questions
The headlights should be connected directly to the vacuum T on the firewall. But if idle changes when you pinch the hose to the headlights, you’ve got a massive vacuum leak somewhere in the headlight system.
Calicat;
Only if it’s a 1970. Earlier Cougars it would t from a port on the manifold. Usually where the brake booster gets its vacuum from.
I agree about the vacuum leak.
Baruden, If you have needed to add brake fluid, but not seeing any leaks along any of your lines or connections, and if no fluid leaks on your brake backing plates by your rear wheel cylinders or around your front calipers, you may have a leak on your master cylinder piston into your vacum booster.