Disc brake drag

[Frank Lee]

Piwoslaw, thanks for quantifying this... although I'm sure it varies greatly case-by-case. I always like to say that making sure none of the brakes are dragging should be one of the very first things to check when tuning up or ecomodding. I'd wager dragging brakes happens much more often than people think.

[lowglider]

Nice to hear that you sorted it out.

A tip from a good mechanic I once heard:
From time to time (let`s say once a month) while standing still step on the brake pedal as hard as you can until it goes all the way down, do this three times. And use a lot of force, don`t worry about destroying anything.

What this does is makes the hydraulics work all the way and increases the life of brake cylinders, while it also makes for smoother brake discs and improves brake life.

I had some rust on the rear discs and after doing this it is all gone and smooth as ice. Doing this not only prevents corrosion buildup and improves disc and pad life, but also maintains the shortest emergency braking distance.

[polaris9898]

I recall a story about Tesla's design and development. They found that reducing the drag on the brakes like the go karts. Allowed them to go 2-3 miles in their total commute on battery.

[4mula]

Originally Posted by Daox

Both of my cars have springs on the pads to move them back after you're done braking...

Could you tell any difference in coasting? MPG? Braking? And do you have any pics you could show us? Thanks

I'm mostly thinking it could help my coast down

[Piwoslaw]

Oooo, pictures, pictures! My car doesn't have springs in the brakes, and it seems that the brake dragging keeps recurring Can springs be somehow retrofitted?

[pounsfos]

you've give me something to do today now

*grabs jack*

[Daox]

The setup is pretty simple. On the end of he brake pads there is some way to hold the spring. They insert a wire/spring into the holder to push against the other pad. Here is a google image. The spring would be item 12.

[Christ]

Are we sure those are r return springs and not j just anti-rattle clips? As I'm sure you know it takes a good bit of ossie to relieve the calipers when changing brake pads... S springs so small seem more like they'd just be designed to keep the pads from rattling at the onset and release of braking.

[Piwoslaw]

Originally Posted by Christ

Are we sure those are r return springs and not j just anti-rattle clips? As I'm sure you know it takes a good bit of ossie to relieve the calipers when changing brake pads... S springs so small seem more like they'd just be designed to keep the pads from rattling at the onset and release of braking.

Googling around found this Miata forum, and this Miata how-to, which suggest they may be anti-rattle, but may be able to keep the pads off the rotors also. I think it's not about the springs using lots of force to pry the calipers far away from the rotor almost instantly, but just enough to barely move it away, or just enough to keep them from moving back on their own. Just my guess.

[zonker]

the wire springs are anti-rattle clips. one could argue that even an minute amount of beneficial tension is going to help the anti-drag cause, but my money bets the anti rattle spring's contribution is insignificant.

i think the best contribution one could make with reducing drag is making sure all pins and sliders are lubed to allow free movment of the floating caliper.

also... one more thing to consider is the parking brake adjustment of rear disc brakes.

On a ZX2 for example, behind an access bolt on the rear of the caliper, an allen set screw exists that limits retraction of the caliper piston.

this is done so the parking brake cable mechanism has a reference upon which to pull against. one can use this allen screw adjustment to gain additional clearance between the pads, much like one would use a star wheel adjuster on drum brakes.