Brake Fade
 

Hey Ya'll

At Collie on the weekend, my kept experiencing Brake fade quite severe.
within 2 laps of the track 1st time out, by the last corner heading onto the straight, the pedal was just about at the floor & every run after that within 6 decent applications of the brakes, they were done.

Now im researching into which fluid to put back into the system as the fluid ive got atm
a. i dont know enough about it - it was from my old mans work ( renault ) as spare UNOPENED fluid.
b. It clearly isnt doing the job.

Im looking at this fluid.
[url=http://www.vsport.com.au/ecommerce/index.php?productID=219]Brake Fluids - Sport Evo 500++ Brake Fluid[/url]

It appears to be what im after.

Has anyone used this or can they recommend another fluid to get?

Now also When bleeding the brakes, the brembos have 2 Bleed nipples on the fronts - Am i supposed to bleed out of both sides?

Cheers
Dave

For the brembos, follow the subaru diagnoal brake bleeding procedure (will dig it up in a sec) and bleed both nipples (heh, nipples) from the inside of the wheel well outwards.

As for the fluid, get a few bottles and flushout the whole system while you are there. I also imagine you could reduce the problem with better braking technique but that comes with time.

Now as for the brakes themselves, pedal to the floor is fluid, but when you were STANDING on it, did the car still pull up?

Yeah, what pads/rotors you running Dave?

John, Front Rotors are RDA Blanks, Rear Rotors Are Stock, Pads Are QFM A1RM's Front, Rear Are Genuine Brembo/Subaru/Stock Pads.

Mat(t) - Found the procedure :-D

Even standing on them didnt pull the car up quickly, saying that they felt a bit all over the place ( Where the bite was) when they went soft.

I have only done 3 track days on the pads and rotors. checked the pads, they still have plenty of meat but the rears are just about done.

This is the link you want

[url]http://www.perth-wrx.com/vb/diy-mechanical-modifications/10887-diy-those-bleeding-their-brakes.html[/url]

Personally on my becauseracecar I ran the cheap Castrol fluid and just flushed it every event or two. Maybe if I was doing more laps (racecar) I'd consider buying something super expensive.

Reading the site your pads would be on/past their limit as a street / track pad.

Welcome to Collie.

Warning, Collie is hard on brakes :P

QFM A1RM's seem to be good brakes from what i have been seeing, what are the costs for gc8 4pots/1 pots does someone know?

also saw some motul brake fluid at auto pro dot 5.1 for 25 a pop for 500ml, anyone know if its any good?

could someone reccommend a good fluid for daily duties? e.g is castrol super dot 4 good or bad silver bottle?

Any brand DOT 4 changed regularly is good for light track / daily.

A 780 degree pad is too little for Collie?

Also, I would guess you had the same issue I had a while ago. Pads/rotors would be fine, but fluid was dead causing f'all pedal and pedal dropping to the floor right when you don't want it.

Replace with fresh fluid and all is good again. Before circuit events like Collie, prolly a good idea to bleed through some new fluid.

[QUOTE=Kato;604793]Any brand DOT 4 changed regularly is good for light track / daily.[/QUOTE]

The Fluid In atm in mine is DOT4

[QUOTE=GTB Liberty;604794]A 780 degree pad is too little for Collie?[/QUOTE]

Any pad that is labelled a street / track pad is eventually going to struggle anywhere. They did the job ( Dave didn't smash into anything ) but unless it's a track spec pad the confidence in them will start to diminish but they will still work, just.
Collie is just so tough because they don't have much of a chance to cool down between corners unlike Barbs where there are longer straights to get a bit of air through them.

[QUOTE=GTB Liberty;604794]A 780 degree pad is too little for Collie?[/QUOTE]

I used ex Indycar brake pads at Collie once. They didn't get warm enough and chewed through the slots in my discs in 6 laps. doh!

as a daily, changed regularly as in 25 thou or earlier?

[QUOTE=XT43;604802]Collie is just so tough because they don't have much of a chance to cool down between corners unlike Barbs where there are longer straights to get a bit of air through them.[/QUOTE]


Pretty much the truth there andrew,
Collie is hard on brakes, i didnt think it was going to be that bad, but considering that i was on the brakes consistantly from 120km/h down to around 70-80 every 15-20 seconds, the heat soak built up in them DAM quick. Especially on the back straight, i was approx 150km/h down to 60-70 for the chicane, then 15sec later, 120 back to 60 for the main straight.

Cheers For the input guys,

Ill grab 2 bottles of the brembo stuff, flush them completely, and grab some new rear pads.

how about water cooled brake set up?

ferodo ds3000's and a rubbish set of rotors were still good to me at collie

with similar speeds to you dave, i didnt have fade at all, but they did dust up a little.

plus i hadnt even bled the system through for over 12 months

[QUOTE=tuna;604832]ferodo ds3000's and a rubbish set of rotors were still good to me at collie

with similar speeds to you dave, i didnt have fade at all, but they did dust up a little.

plus i hadnt even bled the system through for over 12 months[/QUOTE]

I think the QFM A1RM's are set against the ds2500s, obviously the 3000s being a step up into track spec so that may shed some light..

I cant remeber you saying they were an issue at Barbs Dave?

I have QFM's and was hammering them because I couldnt get the car to turn so needed to slow down pretty badly.

No fade issues with shitty 2 pots

[QUOTE=XT43;604836]I think the QFM A1RM's are set against the ds2500s, obviously the 3000s being a step up into track spec so that may shed some light..

I cant remeber you saying they were an issue at Barbs Dave?[/QUOTE]

Nope, were all good till the 2 runs of the night, started to fade then

I didnt have any brake issues at Collie, but I wasnt pushing as hard as most cause of my back.

Running QFM A1RM pads front and rear, DBA 650S Slotted rotors on the front, standard solid discs rear.
Total DOT 4 fluid.

I would just go the Castrol Super Response Dot 4. It's cheaper than that brembo fluid and it has similar dry/wet boiling points.
I've got a layer of break pad material about 1.5cm wide on the disc, need to clean that off. Besides that, the car pulled up nice (stock rotors and A1RMs on the front)

Adi

Just dont ever go Proflex discs. Look what happened to poor Gordon on the weekend.
Few runs at Collie and both virtually new front discs cracked.

I run DBA 4000 slots, bendix ultimate pads, brembo fluid, little fade on back to back runs, best time is a high 53 around Collie, but could be better once overboost is solved.

Dave, is this still the same fluid you used at the last no limits??? You said you were going to change it over then. If you need a hand let me know and you can come round and we'll do it at mine.


Sent from my iPhone using Tapatalk

[QUOTE=Saint_23;604884]Just dont ever go Proflex discs. Look what happened to poor Gordon on the weekend.
Few runs at Collie and both virtually new front discs cracked.[/QUOTE]

They weren't new, He'd done 10,000 km on them without issue (apart from smoking his Lucas pads) before having them machined & fitting QFM pads.

Gordo thinks he didn't bed them in fully after having them machined prior to Collie... he said he felt them start to shudder after his second lap....they'd only done 500km since machining/new pads.

I had the exact same discs (protex Ultrastreet) hot enough to burn the paint off the hubs last time I did Collie & still have no cracks 30,000 km later?

My car is due for rear discs in a month or so.....will be going RDA slotted rears.

I used castrol super dot 4 on qfm a1rm pads all round, with dba4000 up front and stock rotors up back.

Flushed it a couple of days before the event, and only got fade/shuddering after 3 sets of laps back to back.

[QUOTE=Rossco;604953]They weren't new, He'd done 10,000 km on them without issue (apart from smoking his Lucas pads) before having them machined & fitting QFM pads.

Gordo thinks he didn't bed them in fully after having them machined prior to Collie... he said he felt them start to shudder after his second lap....they'd only done 500km since machining/new pads.

I had the exact same discs (protex Ultrastreet) hot enough to burn the paint off the hubs last time I did Collie & still have no cracks 30,000 km later?

My car is due for rear discs in a month or so.....will be going RDA slotted rears.[/QUOTE]

10k old discs, even with a recent machining still shouldn't have cracked.

Ok, firstly, don't shit on Protex discs because Gordo cracked one. I've cracked every kind of disc, they all do it eventually.

Secondly, I doubt you had fade Dave, I didn't in exactly the same car and I reckon we were doing similar times. I suspect you had knock off. Anything 100mm hub with Brembos and decent tyres will get it. It's when the wheel bearing flexes enough that the huge rotor diameter pushes the pads back just enough that you get a long pedal. It'll pump up hard on the second pump, or give it a light pump with your left foot after a hard corner (like the chicane is a good example)

[QUOTE=dtrally;604959]Ok, firstly, don't shit on Protex discs because Gordo cracked one. I've cracked every kind of disc, they all do it eventually.

Secondly, I doubt you had fade Dave, I didn't in exactly the same car and I reckon we were doing similar times. I suspect you had knock off. Anything 100mm hub with Brembos and decent tyres will get it. It's when the wheel bearing flexes enough that the huge rotor diameter pushes the pads back just enough that you get a long pedal. It'll pump up hard on the second pump, or give it a light pump with your left foot after a hard corner (like the chicane is a good example)[/QUOTE]

Ah ok. It would explain it but is this just a nature of the beast or something that can be reticified?

If you were racing it you'd renew the wheel bearings every race, in the 12 hour endurance every pit stop.

You could update to the newer hubs that have a bigger bearing but I wouldn't bother, just learn to live with it and drive to minimise it.

Do this test. Drive up a wide quiet road or the freeway at night and swerve side to side several times without touching the brakes, get some cornering forces happening. Then see if you get the long pedal. If so, it's definately knock off.

Wasn't intentionally trying to shit on a brand. Apologies if it reads that way.

However, I think that given the age/condition and set of circumstances under which they discs cracked,
I would think twice now before purchasing the same product.

I would actually be really interested in seeing the material composition of the disc to try and determine why
they did crack. Unfortunately without know the temperatures they were at at the time it wouldn't really help
at this point.

Drilled rotors will always be more prone to cracking. Usually it's shock, temperature related. Getting really hot then suddenly cooled by water or wind etc. Both of which were in abundance that day.

[QUOTE=dtrally;604964]If you were racing it you'd renew the wheel bearings every race, in the 12 hour endurance every pit stop.

You could update to the newer hubs that have a bigger bearing but I wouldn't bother, just learn to live with it and drive to minimise it.

Do this test. Drive up a wide quiet road or the freeway at night and swerve side to side several times without touching the brakes, get some cornering forces happening. Then see if you get the long pedal. If so, it's definately knock off.[/QUOTE]

Ok ill give that a crack.

[QUOTE=Master D;604973]Ok ill give that a crack.[/QUOTE]

Haha, you said "crack"

[QUOTE=Saint_23;604966]Wasn't intentionally trying to shit on a brand. Apologies if it reads that way.

However, I think that given the age/condition and set of circumstances under which they discs cracked,
I would think twice now before purchasing the same product.

I would actually be really interested in seeing the material composition of the disc to try and determine why
they did crack. Unfortunately without know the temperatures they were at at the time it wouldn't really help
at this point.[/QUOTE]

It's all good Dave.

Speculatively speaking: My dumb logic is that the machining removes the chamfers around the cross drilling holes creating stress risers around the circumference of each hole.

All I can say about the material used is that it's hard compared to RDA slotteds I've used before.
I had EBC greens in with the Protex discs for the first 25,000km before the pads were down to 5mm & I fitted the QFM's. The wear on the rotor face was negligible at the pad change.

I had Ebc greens on RDA slotteds in my last WRX and the rotors wore at similar rate as the pads, once the pads were at 5mm the discs were throw away....But meh, RDA's are damn cheap! :)

There are not much interval for it to cool...
Both my front center caps went popped during my last collie and poor Adz have to run chasing the rolling center caps, all due to heat.

Went couple of circles in the open carpark to cool but obviously it wasn't cool enough.

I have found the best (Brembo) combo for Collie...and for that matter Barbs, RAC etc is DBA 5000 (never cracked one...rotor that is!), Pagid RS29 (19), Brembo fluid... do it once, do it right.
Best Subaru 4 pot is as above except Pagid RS4-2
Saving money on braking is a false economy...