# brake drag... and reducing it



## Roy Von Rogers (Mar 21, 2009)

http://www.freeasestudyguides.com/brakes-dragging.html


Roy


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## McRat (Jul 10, 2012)

IIRC, most modern disc brakes have the pistons at a slight angle, so when you release the brake, there is little or no drag.

Could be wrong.


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## cpct (May 31, 2012)

If all is well, the pads should really retract from the disc just enough not to cause noticable drag. If not, it's time to clean the area around the pistons and the pins where the pads "slide" or get the calipers apart and do a "full clean".
At least, that's what I do on my motorcycle.


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## Ziggythewiz (May 16, 2010)

Most disc brakes have no spring or other mechanism to retract the pads other than slight wheel wobble.


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## McRat (Jul 10, 2012)

Ziggythewiz said:


> Most disc brakes have no spring or other mechanism to retract the pads other than slight wheel wobble.


Best way to verify is to lift up a wheel and turn it. Very little drag on late model stuff compared to early discs.


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## Roy Von Rogers (Mar 21, 2009)

Also the seal around the piston is suppose the retract by a minute amount.

Roy


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## PStechPaul (May 1, 2012)

Here is a discussion of the action of caliper brakes, although more for bikes than cars: http://www.socaltrailriders.org/for...ke-piston-retract-when-you-release-brake.html


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## dtbaker (Jan 5, 2008)

cpct said:


> If all is well, the pads should really retract from the disc just enough not to cause noticable drag. If not, it's time to clean the area around the pistons and the pins where the pads "slide" or get the calipers apart and do a "full clean".
> At least, that's what I do on my motorcycle.


yeah, there's a fair amount of old and new dust built up on the calipers and probably the slides. How about specifics on good products (grease) that won't gum things up, or run into wrong places as calipers heat up? i.e. any favorite types or brands that seem to work best?

should pistons, under the rubber dust cups, be lubricated with anything or not?


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## McRat (Jul 10, 2012)

I grease the caliper pins if applicable, use blue loctite, clean stuff with brake cleaner, but nothing else normally is needed. If you have anti-vibration paste, put it on the back of the pads.

Rotor and pads must be clean.


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## cpct (May 31, 2012)

dtbaker said:


> yeah, there's a fair amount of old and new dust built up on the calipers and probably the slides. How about specifics on good products (grease) that won't gum things up, or run into wrong places as calipers heat up? i.e. any favorite types or brands that seem to work best?
> 
> should pistons, under the rubber dust cups, be lubricated with anything or not?


The main rule is: Under no circumstances should one ever put grease or lubricants on brake parts! There is always risk of it getting in the wrong place (ie on the disc or pads). I know, it's what you basically said already 

Ofcourse, if done with reason, there are exceptions; e.g it's common practice to put high temp copper grease on the back of the pads to prevent brake squeal.

As to putting lubricant on the pistons, it will likely degrade the rubber seals and maybe the brake fluid itself.
Normally, there is a rubber boot around the piston that provides adequate protection. You should just ensure that no dirt or grit gets inside it, or the piston will begin to wear (pitting) and weep brake fluid. This is quite common on old motorcycles, but then their brakes catch more dirt than a car's...
I suspect it's that kind of rubbish around it that prevents the piston from properly retracting.


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