February 24, 2012
Dear Tom and Ray:
I love your show, and I desperately
need your help. I am presently the
“keeper” of my 25-year-old daughter’s
2004 Nissan Maxima. It has a serious
problem, which she also has mentioned.
On any cold (34 F or below) winter
morning, the power brakes are NONEXISTENT.
Like, GONE for the first five
to seven minutes after starting the car. If
you let the car warm up for 10 minutes,
they’ll kick in. But if you try to head
right out onto the road (which I have
been crazy enough to try), you have virtually
NO brakes. I can pump the brakes
really hard and ease to a stop if going
less than 1 mph — seriously. Mechanics
have suggested everything from the
transmission to the master cylinder to a
brake line to a vacuum problem. Please
help! I don’t want to be a kamikaze driver
RAY: We don’t want you to be one
either, Sharon. After all, we could be in
the car in front of you.
TOM: The first thing I’d suspect
would be the power-brake booster.
RAY: The power-brake booster is a
device that uses a vacuum-operated
diaphragm to multiply the pressure your
foot applies to the brake pedal. It’s the
“power” in power brakes.
TOM: If water has gotten inside the
diaphragm, or into the line that runs to it,
it could be freezing overnight and preventing
the booster from working
because the ice is blocking the flow of
RAY: Then, once the engine compartment
heats up, the ice melts and the
booster works normally.
TOM: We’re so used to having power
brakes these days that when the “power”
part fails, it feels like we have no brakes
at all. And today’s heavier cars are much
harder to stop without power brakes.
RAY: This should be pretty easy to
diagnose, Sharon. One option is to simply
put a booster in it. I think there’s at
least an 86.75 percent chance that that
will solve your problem.
TOM: Otherwise, you’ll have to leave
the car overnight with your mechanic.
RAY: First thing in the morning, while
the brakes are actually misbehaving,
your mechanic can poke around and figure
out exactly what’s going on.
TOM: In the meantime, stay off the
road until your brakes are fully functioning.
Remember, body work generally is
a lot more expensive than power-brake
* * *
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