A brakes question.

[Bill Douglas]

On the SC the brakes are wonderful. I could take my hands off the wheel at 60mph and slam on the brakes, and the car would stop in a straight line.

But... I was crawling forward, gearbox in neutral, going slightly down hill and I could hear a brake pad rotor noise.

I've put the car up on the hoist and turned the wheels and all of them make a little bit of noise some or most of the way around when the wheel is turn by hand.

This suggests the pad is dragging to some extent, but I don't know what is OK and what isn't. I went for a drive without using the brakes then immediately put my finger on the calipers then the rotors, on all four wheels, and they were all cold. So if it is dragging, it isn't by much.

What are your thoughts? Is this normal? I was going to remove the calipers from the rotors and decompress the pistons a few times to free things up. But I don't want to if I don't have to.

[Trackrash]

Noise? Could be some grit or gravel caught in the calipers.

If you spin the wheel by hand and it continues to spin, I would call that good, considering you say it brakes straight and true and they are not heating up.

How long has it been since you changed your brake fluid? Might be a good time to do a complete flush. At when you are bleeding you could push each of the pistons back in the caliper. No need to remove the calipers.

How old are your brake hoses?

[Bill Douglas]

Thanks Gordon. The brake fluid is about three years old and the hoses are good, umm brake hoses are about ten years old but they get checked every six months. So I can jam a screw driver in there and force the pistons back into the caliper when I do a brake bleed?

[Bill Verburg]

Originally Posted by Bill Douglas

On the SC the brakes are wonderful. I could take my hands off the wheel at 60mph and slam on the brakes, and the car would stop in a straight line.

But... I was crawling forward, gearbox in neutral, going slightly down hill and I could hear a brake pad rotor noise.

I've put the car up on the hoist and turned the wheels and all of them make a little bit of noise some or most of the way around when the wheel is turn by hand.

This suggests the pad is dragging to some extent, but I don't know what is OK and what isn't. I went for a drive without using the brakes then immediately put my finger on the calipers then the rotors, on all four wheels, and they were all cold. So if it is dragging, it isn't by much.

What are your thoughts? Is this normal? I was going to remove the calipers from the rotors and decompress the pistons a few times to free things up. But I don't want to if I don't have to.

probably normal
the primary means for retracting the pistons is the rotor pushing them. Pad knock back is when they get retraced too far.

There is some retraction due to hysteresis in the rubber as well but not much.

The result is going to be a slight drag

[T77911S]

your fine .

you want the pads as close as possible without putting PRESSURE on the rotors.

[Trackrash]

Originally Posted by Bill Douglas

Thanks Gordon. The brake fluid is about three years old and the hoses are good, umm brake hoses are about ten years old but they get checked every six months. So I can jam a screw driver in there and force the pistons back into the caliper when I do a brake bleed?

When I bleed my brakes, I remove the pads, open the bleed screw, push the brake pedal down an inch or so and use a pole to hold it in that position. I then use a pair of channel locks covered with duck tape to push the pistons back into the caliper. I then close the bleed screw, replace the pads and bleed that caliper as you would normally do. Then go to the next caliper.

[Bill Verburg]

Originally Posted by Trackrash

When I bleed my brakes, I remove the pads, open the bleed screw, push the brake pedal down an inch or so and use a pole to hold it in that position. I then use a pair of channel locks covered with duck tape to push the pistons back into the caliper. I then close the bleed screw, replace the pads and bleed that caliper as you would normally do. Then go to the next caliper.

while its a good idea to exercise the pistons every now and then, a safer way to do it is to use one of these to push the pads all the way back in to the caliper, then remove the pads, then replace w/ a worn set of pads(saved just for this purpose), be sure to lube the edges of the pads and the pins that the pads slide on, if any(no where else though)



Much better to use the proper tool, the pistons aren't all that robust and it's easy to go through the crown.

[Trackrash]

I've not seen that tool before. Where are those sold?

[Bill Douglas]

Thanks guys, a wealth of knowledge between us. Also great to get the Bill V brake guru sign off to the situation

[JRSIII]

Not quite as fancy as Bill's, but I got one like this off ebay for less than $20. Just search "brake caliper tool".

[BK911]

Use a laser thermometer and check rotor and caliper temp after a drive.
If one was dragging, it will have elevated temps.
Compare fr with fl; rr with lr.

Visually checking your brake hoses won't help with internal swelling.
At 10 years old I would personally replace them.
But I'm anal like that.

[Bill Verburg]

Originally Posted by Trackrash

I've not seen that tool before. Where are those sold?

Amazon They were ~$60 when I bought mine they seem to have gone up to ~$100 theses days
the name is 4 in 1

The $20 screw type works as well just not as convenient

[Trackrash]

Good to know. The only type I have seen looked more like a speculum. Didn't seem too functional.

I bet I could make a screw type....

BTW, I sometimes use a thin but deep C clamp, if the piston is not cooperating.