Cold Brake Fade

[pitts64]

***UPDATE 6-17-15*****

I just tried the new CARQUEST ceramic disc pads and they are better in every way than the Hawk HPS pads they replaced..

I have a problem with the disc/drum brakes on my 64 Pontiac.
When they are cold, or cool down while on a long non-braking drive, they fade. When I make a few hard stops, they come back and work very well.
The pedal is always hard and everything is new except for the power booster.
I was adjusting the proportion valve and after some hard stops they were working very well I could lock up the fronts with the rears shut off.
I have;
-11-5/32" 77-79 Seville rotors with D-52 (77-78 Caprice)Calipers.
-Brake pads and shoes are Carquest Premium Ceramic.
-Summit adjustable proportion valve on the rea line.
-Raybestos master.
-Master Power Brake metering valve on the front line.
-1/4" lines to the front and rear, should I switch the fronts to 3/16"?

Thank you

[NOT A TA]

I tried ceramic pads and they aren't good cold. I couldn't hold my car on the line while "footbraking" on the starting line at dragstrips and redlighted a couple times because of them.
Every time I forgot to warm them up on my street while using the car for normal driving I'd panic when they didn't stop at the first intersection.

John

[pitts64]

Thanks John, sounds like the same trouble I'm having. To make matters worse, my American wheels are wide open.

Can anybody recommend a good street pad?
Should I switch my front lines from 1/4" to 3/16"?

[NOT A TA]

I'd rather do almost anything on my cars other than brakes but I've learned several things that might pertain to your project.

1. New stock type rotors are almost never straight. Have them cut before you even think about installing them on your car. They will perform better with less pad wear.

2. Pads must be "bedded in" for best performance. This step helps the pads achieve maximum effeciency with the rotor surface. This is done by making a series of slow downs from certain speeds which heats the pads to desired temps based on speed and quickness of the stopping action. A transfer occurs of braking material to the rotor surface. The procedure may vary with pad types and the manufacturers recommendations so check with the company that makes the pads you use.

3. If you change pad composition (like switching from the ceramics)then you have to have the rotors turned and go through the "bed in" procedure with the new pads.

4. Buy a vacume pump to bleed the brakes, makes life a lot better for about 35 bucks.

5. If the system uses DOT 3 fluid I recommend Ford heavy duty fluid. Performance per dollar spent value is very good. Buy it at the dealership. I change fluid often because of track duty and I've tried a number of brands.

6. Use a torque wrench at the correct setting when installing the wheels and retorque after a bit of driving. Lots of people overtorque lug nuts and warp the rotors. Don't assume shops aren't guilty of this. On 2 occasions tire shops have warped rotors on my regular cars overtorqueing with an air gun when getting new tires. I know the brakes didn't pulsate before the new tires were installed. Cutting the rotors and rebedding the brakes is the only solution.

7. After using the brakes at their limit and the brakes are very hot do not hold the car with the brakes as they will overheat. This is why theres always a "cool down" lap on road courses. I learned the hard way during a track event. A drivers test required that everyone on track had to stop. I forgot to get off the brake after the stop untill I smelled the burnt pads and saw smoke!

I've had good experiences with Raybestos Heavy Duty pads and shoes for all around performance. They require a little extra pressure the first stop around town but perform well after the initial warm up stop. They'll hold the car cold on the strip during burnout using linelock when cold and also footbraking on the line when cold. They are also quiet when properly installed. My experiences with the carquest stuff has not been good.

John

[pitts64]

My alignment tech said the same thing about the Carquest pads.