"Hard" brakes in freezing weather

[Allison Turner-]

I've got a problem with my 97 Legacy wagon: in really cold weather
(10F/-12C or below) the brakes are very hard for at least a few
seconds. The colder it is, the longer it takes the brakes to work.
I've been out in 0F/-18C and had to warm up the car for at least a
minute before the brakes are normal.

It would be a simple solution to just warm up the car each cold
morning, except that I'm a firefighter/emt, and need to be on the
road within as few seconds as possible, for those charming 3:00 AM
calls. (Very bad form to crash the car on the way to a call, too.)

And it's not just my car, either. A fellow firefighter has an '03
Outback, that does the same thing. My mother's '03 Forester also
does it, but at least she never needs to be on the road within
seconds.

From what little I've seen online, it sounds like it has something
to do with the power assist / vacuum, and it does feel like the
power assist is not doing any assisting. But for all I know it
could be something completely different.

Anyone know anything about this? Anyone have a solution?


Thanks in advance for your help.

-Allison

 

[clare at snyder.on.ca]

I've got a problem with my 97 Legacy wagon: in really cold weather
(10F/-12C or below) the brakes are very hard for at least a few
seconds. The colder it is, the longer it takes the brakes to work.
I've been out in 0F/-18C and had to warm up the car for at least a
minute before the brakes are normal.

It would be a simple solution to just warm up the car each cold
morning, except that I'm a firefighter/emt, and need to be on the
road within as few seconds as possible, for those charming 3:00 AM
calls. (Very bad form to crash the car on the way to a call, too.)

And it's not just my car, either. A fellow firefighter has an '03
Outback, that does the same thing. My mother's '03 Forester also
does it, but at least she never needs to be on the road within
seconds.

From what little I've seen online, it sounds like it has something
to do with the power assist / vacuum, and it does feel like the
power assist is not doing any assisting. But for all I know it
could be something completely different.

Anyone know anything about this? Anyone have a solution?


Thanks in advance for your help.

-Allison

The check valve in the vac line to the booster is freezing up. The
dealer should have a solution. If not try the check-valve from another
kind of vehicle.

 

[Tony Hwang]

The check valve in the vac line to the booster is freezing up. The
dealer should have a solution. If not try the check-valve from another
kind of vehicle.

Hi,
How old is the brake fluid? More likely it is contaminated with
moisture. Flush and refill. Brake fluid doesn't last forever.

 

[clare at snyder.on.ca]

Hi,
How old is the brake fluid? More likely it is contaminated with
moisture. Flush and refill. Brake fluid doesn't last forever.

And it seldom causes a hard pedal. Hard pedal on a cold day is
virtually allways lack of boost due to either a frozen check valve, or
moisture in the vac. line.

 

[Tony Hwang]

And it seldom causes a hard pedal. Hard pedal on a cold day is
virtually allways lack of boost due to either a frozen check valve, or
moisture in the vac. line.

Hi,
I live in much colder winter out here in Alberta. Never experienced
that. Then I always keep my vehicles in original condition no matter how
old they are.

 

[Rick Courtright]

Hi,

And it seldom causes a hard pedal. Hard pedal on a cold day is
virtually allways lack of boost due to either a frozen check valve, or
moisture in the vac. line.

I can't speak to really cold conditions, as it seldom even gets to
freezing where I am. But, for anecdotal purposes only, a recent change
of brake fluid cured a "hard pedal" in my Camry's brakes. There's lots
of argument on car forums about changing fluid, but I think the industry
consensus favors a change about every two years. It certainly won't hurt.

I've found it sometimes helps w/ "diagnosis" to pump the brakes w/ the
engine off to deplete the vacuum in the system. Then, hold the pedal
down and start the engine. The pedal should "drop" a bit right after the
engine's started, indicating all the vacuum lines are clear and valves
are working.

Rick

 

[Allison Turner-]

clare at snyder.on.ca wrote:

On 4 Jan 2008 19:02:57 -0800, Allison Turner- <(e-mail address removed)>
wrote:

I've got a problem with my 97 Legacy wagon: in really cold weather
(10F/-12C or below) the brakes are very hard for at least a few
seconds. [...]
Thanks in advance for your help.

-Allison

The check valve in the vac line to the booster is freezing up. The
dealer should have a solution. If not try the check-valve from another
kind of vehicle.

Hi,
How old is the brake fluid? More likely it is contaminated with
moisture. Flush and refill. Brake fluid doesn't last forever.

And it seldom causes a hard pedal. Hard pedal on a cold day is
virtually allways lack of boost due to either a frozen check valve, or
moisture in the vac. line.

Hi,
I live in much colder winter out here in Alberta. Never experienced
that. Then I always keep my vehicles in original condition no matter how
old they are.

Thank you, everyone! That was very helpful. Next time I get
to my Really Wonderful Mechanic, I'll have him replace the
check valve (I'm pretty sure he's already tried changing the
brake fluid).

-Allison