97 legacy brakes problem in cold weather

[Mary Land]

My 97 Subaru Legacy Wagon has this intermittent braking problem. When I
start the car in the early morning in the winter (below freezing
temps), an initial depress of the brake doesn't work. However, if I let
off, then depress again, it catches and then is normal.

It happened last year as well in the cold weather only. Anyone else
with this experience?

 

[Limey Lurker]

Change your brake fluid; it's got water in it which is freezing.

 

[Michael Pardee]

My 97 Subaru Legacy Wagon has this intermittent braking problem. When I
start the car in the early morning in the winter (below freezing
temps), an initial depress of the brake doesn't work. However, if I let
off, then depress again, it catches and then is normal.

It happened last year as well in the cold weather only. Anyone else
with this experience?

I go along with Limey Lurker - start with a flush of the fluid. If that
doesn't do it (and especially if you are saying the pedal sinks to the floor
the first time) you are looking at master cylinder overhaul or replacement -
which can be expensive with ABS. But if the pedal is sinking, don't put off
repair. It will soon reach the point where it does that when warm and you
want to stop. Master cylinder replacement is always cheaper than an accident
*plus* master cylinder (or car) replacement.

Mike

 

[S]

Hi Mary!

My 97 Subaru Legacy Wagon has this intermittent braking problem.

I have noticed the same thing on my '96 Legacy on really cold (single
digit) mornings (takes excessive pedal pressure, first couple of
applications, then normal?). I seem to notice this particularly if the
car had not been allowed to warm up all of the way the time before
(corner store/beer run/whatever). I suspect that the check valve in
the vacuum booster line is picking up enough moisture to freeze closed
(or maybe it's just sluggish in the cold; aren't we all?), hence no
vacuum boost until it thaws, or the engine develops enough vacuum to
pull it open anyway. At least that theory is consistent with the
symptoms. It's been cold and snowy here the last few days. Haven't had
the Legacy out, but I'll try it tomorrow AM and see if I can verify
that this is what's happening. The check valve is just a little
plastic thingie; couldn't possibly cost more'n $1000 or so . . . ;-)
I'll scrounge one from the local Soobie yard, work the ol'
swapperoonie on it, and let you know what I find, so stay tuned.
Meanwhile, just let your car warm up a bit longer before pulling out
of the drive, and see if that doesn't alleviate the problem; works for
mine.

ByeBye! S.
Steve Jernigan KG0MB
Laboratory Manager
Microelectronics Research
University of Colorado
(719) 262-3101

 

[Limey Lurker]

I suspect that the check valve in

the vacuum booster line is picking up enough moisture to freeze closed

I don't think I'd've ever thought of that! I'll sure try not to forget
it, though! Thanks!