Question about braking

[houndman]

I'm not very impressed with the braking on my 07' 2.5i 5M Imp. The
soft pedal isn't confidence inspiring in an emergency, even a slight
one, and I noticed with the trans in neutral or clutch in, the brakes
feel a lot stronger, though still too soft. I guess to control
emissions the motor doesn't decel as fast as before emissions, to keep
the mixture optimum, and not go rich, so the the motor is fighting the
braking. I thought that was just a problem with carb cars, but I guess
not. The last stick I owned had Great brakes, but was in the early
emission days. The last 2 have been auto's with carbs, and the brakes
felt good, and both had HDuty brakes and suspensions. I'm assuming the
Sube suffers from the 2 stage vacuum booster, and maybe the mixture
controlling. Anyway, it is good to be able to improve braking, without
having to change the brakes, and I think that requires 17" rims. Might
only have to change the booster, but that needs a different master cyl
also.

VF

 

[S]

Hi VF!

I'm not very impressed with the braking on my 07' 2.5i 5M Imp. The
soft pedal isn't confidence inspiring in an emergency, even a slight
one, and I noticed with the trans in neutral or clutch in, the brakes
feel a lot stronger, though still too soft. I guess to control
emissions the motor doesn't decel as fast as before emissions, to keep
the mixture optimum, and not go rich, so the the motor is fighting the
braking. I thought that was just a problem with carb cars, but I guess
not. The last stick I owned had Great brakes, but was in the early
emission days. The last 2 have been auto's with carbs, and the brakes
felt good, and both had HDuty brakes and suspensions. I'm assuming the
Sube suffers from the 2 stage vacuum booster, and maybe the mixture
controlling. Anyway, it is good to be able to improve braking, without
having to change the brakes, and I think that requires 17" rims. Might
only have to change the booster, but that needs a different master cyl
also.

VF

I haven't driven the newer Imprezas, but my '02 WRX had good brake
feel. Lousy ABS, but good otherwise.

I don't think I'd mess with _anything_ on a car that new before at
least attempting to make it the dealers problem. Before you do that,
tho, try this.

Find an empty parking lot, accelerate to ~30MPH, and stand on the
brakes hard enough to get the ABS to activate. Did it? Do it again,
and try swerving at the same time; if the ABS system is doin' it's
thing you should be able to pretty much put the car where you want it.

Now reach under the dash and pull the ABS fuse. The ABS warning light
should come on.

Try the brake thing again. You should be able to lock the wheels
(you'll hear and feel it) without herculean pedal pressure, mushiness,
steering pull, or other weirdness. Try it with your hands off the
steering wheel. Stop straight?

If you try the swerve w/o ABS, you will either "push" the front end,
or feel the rear start to come around (or both), neither of which is
particularly hazardous (in an empty lot ;-), but it really doesn't
tell you too much, either.

Anyway, if the car passes the above tests, the brakes are most likely
OK, and the pedal "feel" is just different from what you are used to.
If not, bitch to the dealership, and be prepared to demo your specific
gripe from the above.

One thing you might try to improve brake grabbiness would be to
install a set of "performance" pads; all four corners if you can
afford it, but on the fronts at least. This will make significant
difference in "feel", but has possible down sides of increased rotor
wear, excess brake dust, and increased brake noise in general.
Try Hawk, or EBC, and look for something listed for aggressive
street/autocross applications.

Pad swap (especially on a new car, where you don't have to mess with
anything else), is a real easy 5-10 minute per wheel DIY job on an
Impreza. Jack it, pull the wheel, and remove the 8mm bolt (12mm
wrench) from the caliper. (Don't mess with the large bolts holding the
carrier to the hub.) Rotate the caliper off of the rotor (you'll see
when you get that far), pop off the old pads, use a "C" clamp, or
large Channel-loc pliers to compress the piston back into the caliper
body, install the new pads, rotate the caliper back over the rotor,
replace the bolt and reinstall the wheel. Step on the brake pedal a
couple times 'til it firms up (to close the caliper on the rotor, and
prevent brake fluid reservoir overflow) before moving to the next
wheel.

Seriously, probably took me longer to type this than it does to do it.

Hope this proves helpful.

ByeBye! S.

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

 

[L. Ross Raszewski]

Anyway, if the car passes the above tests, the brakes are most likely
OK, and the pedal "feel" is just different from what you are used to.
If not, bitch to the dealership, and be prepared to demo your specific
gripe from the above.

I'd definately try this first. My experience with subarus is that
their stopping power is perfectly normal, but the pedal feels a lot
softer than many other cars (particularly recent-ish cars. I drove a
'05 pontiac not long ago where the brakes felt like you were stepping
on a rock.
(I like the softer pedal myself. Feels like I have more control over
exactly how much stopping power I apply)