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Hot Brakes - Opinions

RubyRS4

By RubyRS4,
in Four Door Family & Wagoneers

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RubyRS4 Grand Master

RubyRS4

Posted
Posted

Need some quick opinions on the limits of my brakes. I'd normally just go to a workshop, but its holidays atm and I'm just doing some homework in the interim.

If I take the stag down a steep hill and apply the brakes to slow down, eventually the brakes complain (getting hot) in the form of what feels like shaking from the front. A bit like a wheel out of balance, but its more noise than anything. Now the CV joints are fine ... there is no shake on cruising, acceleration or any other braking at any time, only when I'm in the hills going downhill and braking. Wheel balance is perfect ... brake discs are not warped. It only does this when going downhill and using the brakes for a prolonged time. Almost feels like the ABS getting hot and assisting, but I feel nothing in the brake pedal (no pulsing), only slightly in the steering and its more noise than 'feel'.

I'm thinking of a brake upgrade anyway, but want some thoughts on the matter. I want to be able to do track days with the stag in the new year.

Discuss.

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KiwiRS4T Grand Master

KiwiRS4T

Posted
Posted

I have never had any problem with stock brakes on the road - but then my normal driving style is not hard on the brakes - but on the track after a few high speed stops they felt on the ragged edge and i started taking it a bit easy on the brakes.

Now I have GTT brakes all round. I have heat treated slotted rotors and Mintex M1166 pads from Racebrakes. I use Motul RBF600 brake fluid. I have a mastercylinder stopper and braided stainless brake lines. Now when I stand on the brakes from over 200km/hr they feel rock solid all day.

pipster11 Grand Master

pipster11

Posted
Posted

r34 gt-t brakes + qfm a1rm pads + slotted rotors = win

thats if its a series 2, if its a series 1 get r33 gts25t brakes (12mm caliper bolts to suit s1, s2 have 14mm bolts like r34's)

this is what im planning to do eventually

KiwiRS4T Grand Master

KiwiRS4T

Posted
Posted
r34 gt-t brakes + qfm a1rm pads + slotted rotors = win

thats if its a series 2, if its a series 1 get r33 gts25t brakes (12mm caliper bolts to suit s1, s2 have 14mm bolts like r34's)

this is what im planning to do eventually

S1 bolts were same as GTT - they bolted straight on my RS4T with the same bolts...may be different for factory manual and/or 2wd.
Duncan Grand Master

Duncan

Posted
Posted

why are you sure it is not a warped disc? I've only ever felt pad or fluid fading as a "mushy" pedal, vibration/noise would only ever be something mechanical, either warped discs or something caught in the wheel/caliper

RubyRS4 Grand Master

RubyRS4

Posted
  • Author
Posted
why are you sure it is not a warped disc? I've only ever felt pad or fluid fading as a "mushy" pedal, vibration/noise would only ever be something mechanical, either warped discs or something caught in the wheel/caliper

Because it only happens when the brakes are hot from a downhill run. I've raced in the past and know what a warped rotor feels like. The rotors are fine, otherwise it would do it all the time under hard braking. Its not a 'mushy' pedal or fade either.

Only ever occurs under braking (heavy or light) after a downhill decent. No violent shake of the steering wheel. No pulsing thru the brake pedal. Goes away once the brakes cool again. I can brake heavy at any other time and there is no pulsing at all, nor any pull left or right to the car.

DSTROY Grand Master

DSTROY

Posted
Posted

Mine is the same, brakes fine under normal conditions, no shakes or anything but get some heat into them in the hills and the steering wheel starts to shake and you can feel the whole car shake and as soon as they cool down they go back to normal.

pipster11 Grand Master

pipster11

Posted
Posted
Well, I'm thinking about 33 slotted rotors and Green Stuff pads and a change of fluid for starters ... see how that improves things.

:D

you can only use r33 rotors if you have r33 calipers, they are different offsets and sizes and you will score the 33 rotor if you put it on and drive

i've also heard very good things about the qfm a1rm pads

_Ryan_ Grand Master

_Ryan_

Posted
Posted
you can only use r33 rotors if you have r33 calipers, they are different offsets and sizes and you will score the 33 rotor if you put it on and drive

i've also heard very good things about the qfm a1rm pads

I would use QFM A1RM over Greenshit.

have used RB74(same as A1RM) and had greenstuff on two cars. I don't use greenstuff on the 32 by choice, it just came with them, so using them up... The feel. bite from cold etc is far superior. and the hotter they get the better they stop. Green stuff you think they will get better when they get hotter and they just don't.

KiwiRS4T Grand Master

KiwiRS4T

Posted
Posted

Ruby going back to SK's original brake thread it would seem if you want to stay with your stock calipers the correct rotors are DBA4909 S (for slotted) and L (for left) and R for right.

These also fit S14 200SX and R32GTST

I haven't done this myself (went straight to GTT) but a few members report that they are correct.

gslrallysport Experienced

gslrallysport

Posted
Posted
I would use QFM A1RM over Greenshit.

have used RB74(same as A1RM) and had greenstuff on two cars. I don't use greenstuff on the 32 by choice, it just came with them, so using them up... The feel. bite from cold etc is far superior. and the hotter they get the better they stop. Green stuff you think they will get better when they get hotter and they just don't.

I would use QFM HPX over Green Stuff, let alone A1RM, which itself will make Red Stuff look stupid.

Also, for those not interested in caliper conversions, we do now have Series 2 Stagea front pads custom made on the shelf ready to go in both compounds. HPX are $119 for the set, A1RM are $179 for the set.

My only input to the original question would be to check the wheel bearings, which can have more play when hot...

_Ryan_ Grand Master

_Ryan_

Posted
Posted
I would use QFM HPX over Green Stuff, let alone A1RM, which itself will make Red Stuff look stupid.

Also, for those not interested in caliper conversions, we do now have Series 2 Stagea front pads custom made on the shelf ready to go in both compounds. HPX are $119 for the set, A1RM are $179 for the set.

My only input to the original question would be to check the wheel bearings, which can have more play when hot...

How far off are Series 1 pads? Rears are same as R31 if that helps... I prob have spare backing plates some where if needed.

M I K E Mentor

M I K E

Posted
Posted

come to think of it, i've experienced this feeling on a drive through the hills too - i actually got out and made sure everything was done up tight (and it was), as soon as i applied any force to the brakes it felt/sounded as if something was shaking

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