The fluid wouldn't freeze, but if there's enough moisture in it, that might freeze.
Think hard -- did you suffer from loss of braking ability or from loss of brake boost?
It's not that uncommon for a little moisture to get trapped in the check valve that's in the brake booster vacuum line. If this freezes, it can prevent the valve from opening which then results in loss of brake boost. You can usually resolve this by warming the hose and then spraying the valve with WD-40 or something.
But this happened while you were driving? Do you have your hood scoop opened up?
"Just reading vrg3's convoluted, information-packed posts made me feel better all over again." -- subyluvr2212
vrg3 wrote:The fluid wouldn't freeze, but if there's enough moisture in it, that might freeze.
Think hard -- did you suffer from loss of braking ability or from loss of brake boost?
It's not that uncommon for a little moisture to get trapped in the check valve that's in the brake booster vacuum line. If this freezes, it can prevent the valve from opening which then results in loss of brake boost. You can usually resolve this by warming the hose and then spraying the valve with WD-40 or something.
But this happened while you were driving? Do you have your hood scoop opened up?
Feels like the booster... I do have a wrx hood scoop, and it has been very cold here. It sounds like it could be the issue you describe. Where is this valve?
Okay, cuz without the scoop I'd think it impossible for this to happen while driving -- it usually happens right after starting the car when it's been parked in the cold.
The valve is in the brake booster hose. About halfway along the hose (between the booster and the intake manifold) you'll feel a hard lump; this is the valve. I don't know if it's possible to remove it from the hose without destroying the hose.
If you have the means I would actually recommend replacing the valve. A good auto parts store will have a cheap check valve.
Also, keep some 3/8" hose in the trunk to replace the entire brake booster hose just in case. It'll work fine without the check valve except that you won't get power brakes while on boost or when the engine's stalled.
"Just reading vrg3's convoluted, information-packed posts made me feel better all over again." -- subyluvr2212
if you hit the brakes while coming down in Rpm's the petal is as stiff as can be, and when the ABS comes on while the petal really wont go to the floor, you can feel the petal sink back to the normal height.
