Hard Braking?

[84porsche]

Guys,

I changed out my brake pads a few months ago for the first time on my car in 3 years. Today while driving, I really came down hard on my brakes and while the car stopped really well, a huge cloud of white smoke appeared from the back. Is this normal? This is the 2nd time this has happened when I have come down hard on the brakes and I don't remember it happening before the change.

[javadog]

Well, if the white smoke was tire smoke fron a locked-up wheel or two in the rear, then it would not be normal or desirable. On a street car, you always want the fronts to lock up first. To start with, do you have the same pads on both ends of the car? What pads are you using? What tires?

JR

[84porsche]

I bought the Metal Master brake pads here from Pelican and the tires in the back are Michelin Pilot Sport P235 60 R15s. They are the same type of brake pads all the way around.

[javadog]

Well, if the brakes are stock, apart from the pads, and the tires are all the same type and age on both ends, you might take a look at the condition of the front calipers to see if the pistons are in good shape. A stuck piston at one caliper can reduce the braking effect on that wheel. If the front brakes are not doing their share of the braking, and the rears are fine, the brake bias can shift more to the rear. Or, you might have a weight balance problem; if the car hasn't been corner balanced in a while, you might have a rear tire that's carrying a lot less weight than the other and locking up a little early. There is also the possibility that the limiting valve isn't working correctly but I think the other two potential problems are more common.

JR