Have i got brake fade or hot brake judder?

olliecast

olliecast

Active Member
UPDATE : Have i got brake fade or hot brake judder?

good morning,
Been trying to get to the bottom of my brake judder and poor peformance at higher speeds to no avail currently.

When braking from say 100 down to 60/50 mph on track its starting to slightly judder (you can hear it as well as feel it) and i`m loosing braking peformance.

i`m using clio 172 discs, evo 2 calipers and carbotec xp10 brake pads.
the disk runout was less than 0,05mm and the thickness of the disk is within 0,005mm all the round both circumference so i`m pretty sure its not dtv (disk thickness variation).
I`ve had my wheels balenced and changed a lower ball joint which has improved it but not cured it.

could i just be experiencing fade or the "hot judder" found at hot braking temperatures,

cheers in advance,
ollie
 
Last edited:
stumo

stumo

Active Member
fade is what it says.....fade, that means your brakes just don't stop you, generally there's no judder.

by the sounds of it the discs are running true enough.

have you checked the top strut mountings or the track rod ends or the jiont where the tre goes into the rack???
 
olliecast

olliecast

Active Member
stumo said:
fade is what it says.....fade, that means your brakes just don't stop you, generally there's no judder.

by the sounds of it the discs are running true enough.

have you checked the top strut mountings or the track rod ends or the jiont where the tre goes into the rack???
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well 0,05mm is well below manufacturers reccomendation for disk ain`t it?

by top strut mountings you mean above the shock absorbers?
definately no play between the track tod end and hub joint, hows the best way to do them going into the rack?
 
P

pulsarboby

Guest
ive got exactly the same prob ollie with my new ksports!
the steering wheel is shaking its head like a demented demon when braking down from a 100+ and i can feel a slight bounce on the brake pedal when driving really slow and touching the brakes. when everythings hot then the problem is worse!

i dont think its the brakes themselves as the hispecs i had before used to do the same thing.
so im gonna replace both the front hub assemblies with known good ones fitted with new bearings, and il let you know if it solves it.
ive got a feeling that it could be an ovulated bearing which causes the hubface to heat up and warp slightly which in turn will make the wheel run out of true when on car (as its bolted to hub) then this would be transferred to the steering wheel and pedal when under harsh braking.

btw i could be talking total bollox but il let you know if im right or not:lol:
 
olliecast

olliecast

Active Member
MORF114 said:
How long have you had the problem and how long has the kit been fitted?
Click to expand...
kit has been fitted for about 2 weeks, done ~200 miles, 100 since bedding the pads in properly.
problem has been since the kit was fitted but the old brakes were really bad so they used to fade anyway before i got to the point i am with my new brakes anyway,

why you ask?

ollie
 
olliecast

olliecast

Active Member
pulsarboby said:
ive got exactly the same prob ollie with my new ksports!
the steering wheel is shaking its head like a demented demon when braking down from a 100+ and i can feel a slight bounce on the brake pedal when driving really slow and touching the brakes. when everythings hot then the problem is worse!

i dont think its the brakes themselves as the hispecs i had before used to do the same thing.
so im gonna replace both the front hub assemblies with known good ones fitted with new bearings, and il let you know if it solves it.
ive got a feeling that it could be an ovulated bearing which causes the hubface to heat up and warp slightly which in turn will make the wheel run out of true when on car (as its bolted to hub) then this would be transferred to the steering wheel and pedal when under harsh braking.

btw i could be talking total bollox but il let you know if im right or not:lol:
Click to expand...
sounds a valid reason mate, let me know if it cures it.

just out of interest, whats the runout of your disks?
 
P

pulsarboby

Guest
dont know tbh as ive not checked, but should be 0 really as there new!
 
MORF114

MORF114

Active Member
Just wondering if you have any pad material on the disc from bedding them in after you bedded them in did you let them cool quite a while you didnt hold your foot on the brake for a bit straight after bedding in? or any other time after the brakes were red hot??
 
MORF114

MORF114

Active Member
try rubbing the whole disc with garnet paper if you have transfered pad material to the disc sometimes you cant see it but it has transfered to the disc. dont use sand paper it will make it worse.
 
olliecast

olliecast

Active Member
MORF114 said:
Just wondering if you have any pad material on the disc from bedding them in after you bedded them in did you let them cool quite a while you didnt hold your foot on the brake for a bit straight after bedding in? or any other time after the brakes were red hot??
Click to expand...
no mate, i specifically kept rolling up and down the bypass for about 20 mins. The brakes were then cool to the touch.
its baffling me!
 
olliecast

olliecast

Active Member
MORF114 said:
http://www.powerbrake.co.za/downloads/tech_01_judder.pdf

Intresting stuff. hope you get your judder sorted mate.
Click to expand...
update everyone:

i`ve checked the runout with the wheel on and it doesn`t seem anyworse that before.

i`ve checkled for play in the wheels and there`s feck all.

looking at the braking surface, there is definately no cermentite formed on the braking surface.

one thing i did notice was an equally spaced dots of pad material left on the disk the other day. i`m wondering if the disk is overheating on the thin section inbetween the cooling grooves. This has now gone now after a couple of days use

bit miffed as i`ve only done ~180 miles on these disks. they also have a lip on them already!

i got them form here, do you think i should return them under warranty or do you think they just might not have beeded in yet?
i read on the lancer register that some people run their brakes in for ~1000 miles!

http://www.brakepartssuperstore.org.uk/index.html

(they`re the clio 172 disks)

cheers ollie
 
Y

youngsyp

New Member
olliecast said:
bit miffed as i`ve only done ~180 miles on these disks. they also have a lip on them already!

i got them form here, do you think i should return them under warranty or do you think they just might not have beeded in yet?
i read on the lancer register that some people run their brakes in for ~1000 miles!

http://www.brakepartssuperstore.org.uk/index.html

(they`re the clio 172 disks)

cheers ollie
Click to expand...
The discs are either very soft or, your pads are very hard. You shouldn't get noticable wear in 180 miles !

I'd send them back and get some known quality disks and pads.

I've just gone for my second set of Mintex M1144 pads and they're excellent. I'd highly recommend them.

And if you're going to go for 'performance' disks, go for cross drilled disks over grooved ones.
The grooves are very aggressive on the pads and are also very noisy generally plus, grooves don't self clean like cross drilled disks do.

That's my opinion anyway ! :lol:

Paul
 
olliecast

olliecast

Active Member
youngsyp said:
The discs are either very soft or, your pads are very hard. You shouldn't get noticable wear in 180 miles !

I'd send them back and get some known quality disks and pads.

I've just gone for my second set of Mintex M1144 pads and they're excellent. I'd highly recommend them.

And if you're going to go for 'performance' disks, go for cross drilled disks over grooved ones.
The grooves are very aggressive on the pads and are also very noisy generally plus, grooves don't self clean like cross drilled disks do.

That's my opinion anyway ! :lol:

Paul
Click to expand...
the carbotech xp10 pads i`m using are really well reccomended in the lancer owners register.

Is it possible the disks could`ve not been heat treated? i`m really confused to the lip they have on them already. Its not like i`ve been track daying the car!?
 
Y

youngsyp

New Member
olliecast said:
the carbotech xp10 pads i`m using are really well reccomended in the lancer owners register.

Is it possible the disks could`ve not been heat treated? i`m really confused to the lip they have on them already. Its not like i`ve been track daying the car!?
Click to expand...
XP10's are track pads, and the Evo's are much heavier cars than the GTiR. I'd expect they're overkill for all but the hardest track work on a GTiR ?!

If the steel they use to make the disks isn't up to scratch, heat treating it will make little difference.
In fact, I've not heard of heat treating brake disks in the 'mainstream' ?! Cryo treating ... certainly !

Paul
 
GTIR-LOZ

GTIR-LOZ

New Member
if you look at most brake companies website they state they do not recommend using cross drilling as it creates weak points on the disc and can lead to premature failure i.e cracking, grooves clean the pads much better than cross drilling, cross drilling is there just for better cooling of the disc/pad etc
 
gtirjoey

gtirjoey

Member
GTIR-LOZ said:
if you look at most brake companies website they state they do not recommend using cross drilling as it creates weak points on the disc and can lead to premature failure i.e cracking, grooves clean the pads much better than cross drilling, cross drilling is there just for better cooling of the disc/pad etc
Click to expand...
i used to think this but jus look at amg mercs etc etc.. they have cross drilled discs surely if there was a problem with them you would not see them on standard cars??
jus a thought??
 
GTIR-LOZ

GTIR-LOZ

New Member
i work for mercs and you only see them on sports pack vehicles (prob for looks) and amgs if you look closely at the drill holes they almost all have small cracks forming from them (unless they are new obviously) and the brakes are a hell of a lot thicker than your standard wilwood discs so can prob put up for it for a while
 
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