How to tell if you've glazed your pads?

[RtN]

Like the title says.. how do you tell if you've glazed your pads without taking it off? Can you tell from looking @ the rotors?

[xtc.thai]

if ur brakes squeal when braking

[dsp26]

Like the title says.. how do you tell if you've glazed your pads without taking it off? Can you tell from looking @ the rotors?

take it off, it's the safest way to tell. there is a variable amount of 'glaze' causing various effects....

had glazed pads one time.. couldn't stop in time and ended up in the middle of an intersection with smoking brakes. and this was from 60km/h and pressing the brakes as hard as i could including the handbreak and leaving the car in gear to allow engine braking too...

but thats coz they were new pads and i forgot about the break in procedure....

[bennjamin]

as above , tell tale signs are squeeky sounding brakes at little application , and decreased brake feel and power
easy fix (reassurance) is to take the pads out , slide across a piece emery paper or even a gutter a few times to roughen up the surface. Re einstall , drive off and reapply the brake bed in process

find an empty length of road , drive to 50 or 60 km/h and apply the brakes hard to almost 0km/h ease off and drive up to the same speed again , apply brakes again and repeat. do this several times and then ease off entirely , slow down and stop the car on a flat surface and let the brake pads cool down (if possible rest the car in gear with te handbrake down to keep it stationary)

[RtN]

Thanks guys.. hmm might get some new set up soon nothign too good... just maybe Bendix Ultimates, Brembo slotted (BLING), Goodridge Brake lines. Should be enough... anyone know one long open road near Cabramatta/Fairfield? lol

[aaronng]

You know when you press the brake pedal, you feel the pedal resistance, but your car is not slowing down and the first thing that comes out of your mouth is "Oh SHIT!"

[dsp26]

You know when you press the brake pedal, you feel the pedal resistance, but your car is not slowing down and the first thing that comes out of your mouth is "Oh SHIT!"

lol:thumbsup::thumbsup:

[IZY-10]

hi im just wondering if they squeel when they are cold could this be the same issue?

[aaronng]

hi im just wondering if they squeel when they are cold could this be the same issue?

No, squealing and glazing are different. When your pads are glazed, you have reduced braking ability.

[RtN]

Hmm yeh I have some reduced braking ability I believe.. haven't been driving this rice machine much but last time was on Parramatta Rd.. was pretty scary at one moment but yeh lol it eventually slowed me down to a stop.

Hmm anyone got a place to bed in their brakes?

[dsp26]

Hmm yeh I have some reduced braking ability I believe.. haven't been driving this rice machine much but last time was on Parramatta Rd.. was pretty scary at one moment but yeh lol it eventually slowed me down to a stop.

Hmm anyone got a place to bed in their brakes?

if their already glazed do as bennjamin said in post#4 and remove and scrub them with sandpaper

[migoreng]

Thanks guys.. hmm might get some new set up soon nothign too good... just maybe Bendix Ultimates, Brembo slotted (BLING), Goodridge Brake lines. Should be enough... anyone know one long open road near Cabramatta/Fairfield? lol


lol just go down to the motorway at night and stop/start around the shoulder/lanes when no cars are around..

[aaronng]

Scrub them with sandpaper first. Then go and bed them in.

[RtN]

yup got it, but running out soon so decided to get new pads. Might as well since i'm going to take it off will do for next time if anything happens. Thanks.

[JohnL]

You know when you press the brake pedal, you feel the pedal resistance, but your car is not slowing down and the first thing that comes out of your mouth is "Oh SHIT!"

Exactly the same symptoms you get with overheated pads, like you can very suddenly get after you've given them a real caning (even with reasonably good pads), or while trying to stop hard just once from higher speed, with crappy pads.

[Limbo]

don't they just squeel alot?

[aaronng]

Exactly the same symptoms you get with overheated pads, like you can very suddenly get after you've given them a real caning (even with reasonably good pads), or while trying to stop hard just once from higher speed, with crappy pads.

On mine, I still had braking force when the pads were hot. But once they cooled down, they were like braking on glass.

[JohnL]

On mine, I still had braking force when the pads were hot. But once they cooled down, they were like braking on glass.

That would be glazed, which means you actually melted the surface of the pads. Your glass analogy is right on the money because when the friction material cools and solidifies it forms a glass like substance on the pad surface (technically, it is actually a 'glass', a term covering a lot of different substances including uncooked pasta...).

When pads overheat they may or may not melt at the surface, but instead give off gas (seen as smoke) that forms a microscopically thin high pressure gas layer between the pads and the rotor surface that in effect lubricates the friction surfaces, i.e. gas has a very low co-efficient of friction. This 'gassing off' can occur very suddenly, so all of a sudden you can go from having decent brakes to almost none (oh shiiiit...). This 'gassing off' means that gas is being formed at a rate faster than the rate at which the pad pressure can squeeze it out from between the pads and rotor.

This is why 'performance' rotors have slots, and in some cases holes venting to the internal cooling vanes, i.e. to provide a pathway for the gas to more easily escape from between the pads and rotor surfaces. The slots you see on many pads is also there for the same purpose.

'High performance' pads are designed to resist gassing up, so you might melt the surface before gassing up rears it's ugly head...