On my stock ITR brake setup with Mintex 1155 pads front and normal street Mintex pads on rear, ss brake lines and DOT 5 fluid.

During hard braking, the rear seems to be a little unstable/unsettled and not doing my confidence much good. During my track session last year on this setup it seems to be OK but now spirited street driving I noticed this problem is becoming more evident. What could be the cause?

 

Why are you running DOT 5 brake fluid?

Don't brake and turn at the same time, that is where the instability is coming from.

Unless of course you're referring to the slight wandering that the rear will do when braking from high speed, which is natural.

 

Do you have stock suspension? What are your alignment settings?

 

DOT 5 cos before I upgraded, I had serious fade and fluid boiled after 20min session on track...

With new setup, I braked from 110mph to about 40 (straight line before s bend) without any trace of rear wandering....

Just became more and more evident recently...hmmm, maybe its just me..

 

Stock suspension. Could it be the wheels? When I tracked the car I had stock wheels but now I have 17" but I must say that I've had 17" for a while now, only just starting to notice the prob...

 

Yes only occurs when braking from high speed. Alignment is as close to stock as possible (can't remember readings...)

Stock rear wing is on.

 

Switch to DOT 5.1 brake fluid.

You do not want to be using DOT 5 brake fluid as it does not absorb moisture. Over time, beads of water can collect in the calipers and with high heat you may experience vapor lock.

DOT 5 brake fluid is only good for show kaas because it is not corrosive and friendly to paint.

 

Your right. Sorry my mistake, its 5.1 I've got.

 

did you get the car re-aligned after switching wheels??

get a re-alignment done - that should help


toe-out the front a bit - that way you get better turn-in and less toe-in during braking.

zero toe the rear


[Modified by Big Phat R, 4:26 PM 3/12/2003]

 

Yea, re-alignment was done after 17"s. I found the readings, was done 6mths ago so might not be the same now..:

Left fr- Camber: -0.54' Toe: +0.01'
Right fr - Camber: -0.39' Toe: +0.01'

Left re- Camber: -1.28' Toe: +0.07'
Right re- Camber: -1.36' Toe: +0.08'

So whatdya think??

 

Add another degree of negative camber to the front and set the rear toe to zero.

 

you have toe-out on the rear - get rid of it

 

So u guys reckon that this is the culprit and doing this will help?

Thx.

 

My thoughts is that as the brake is biased to the front, it'll be better for track use to have a softer compound on the rear which is why I stuck with stock Mintex at the rear. I think I'll match them up as you said to see the difference on my next pad change.

 

The first (cheap) thing to do is remove the power steering belt. My car took on quite a different feel once I had the belt off.

 

What exactly do you mean by different feel? Steering? braking? taking bends?

 

different feel = the rear end felt less floaty and wagged less.

the belt removal did not effect the steering or taking bends... only the feel of the rear end of the car under heavy braking.

 

By removing the power st belt, do you mean you no longer have power steering? I can't see the logic of how not having power steering will effect the rear end?

 

Suck it up dude. We run fwd cars. The back of the car is primarily there to keep the gas tank from dragging on the ground It's gonna get light if you brake hard.

I have yet to run a fwd Honda that brakes as stable as my E30 M3.

Warren

 

correct.. and I plan to remove the system soon.

It does effect it.
The OE power steering is over-boosted which results in the front end easily turning under heavy braking.

The rear is lighter under heavy braking and will tend to sway back and forth as the rear abs tries to keep everything under control.

If a 'free' suggestion to help your issue is not good... try a more aggressive rear brake pad.

 

swlabhot - This may help you cos it sounds similar to a recent experience I had.

I have DC2 with Mintex 1155s up front and OEM rear, I was coming along a straight I know last weekend and wasnt caning it too much, and I braked as usual and the rear end of the car felt unstable/unsettled - it was strange feeling and a little unnerving.

Id never felt that before and I have had the car on track and owned her for 2 years, so am kind of familiar with how the rear end feels when its rattled or becomes unbalanced - this wasnt like that.

The following day I was caning her for about 20 minutes or so, and I got brake fade - which was really unusual. So i took it steady and let her cool down and bled the brakes that evening.

Anyway to cut short - after flushing the fluid and putting fresh stuff in she seems really good again, what I did notice was a lot of air come out of the rear left section of the brake system.

All I can conclude is that the air in the rear part of the system is what made the rear of the car feel unsettled under braking the day before, you could argue that the air was caused by my fluid boiling, but now everything seems fine I am begining to think the air was there earlier.

I maybe totally wrong but its worth a try before you start looking at everything else.




[Modified by benmasters, 6:11 PM 3/13/2003]

 

Oh by the way were you running the mintex when you got the fade?

I am currently using DOT 4, and when i got brake fade last weekend I was a little miffed as to why i got it considering I wasnt been too hard on the brakes. I spoke to a guy whose girl has an MR2 and she boiled her fluid about 20minutes on the track also and she is using Mintext 1155 pads!

All seems a little weird. I am intending to upgrade to 5.1 now anyway.

 

Grandpa, Willard - I guess it make sense and this was in my thoughts before but I just didn't think that it'll effect it AS MUCH as feeling as tho I could loose the rear end totally at some point if I had braked ever harder at greater speeds....

Guess, I'll match up the pads and see how much difference it makes.

 

When I had serious fade, I was on a completely stock setup. After this was when I changed to DOT 5.1, ss lines and Mintex and since then ZERO fade on track and its also wearing and lasting very well.

I think your fluid was prolly expired and needed changing from the fade you had. DOT 5.1 may not always be better than DOT4. In fact some dot 4s have a higher boiling point than 5.1. Wet and dry boiling points can vary a lot.

I guess my rear calipers seizing up could also be a possibility as I realised the rear left did before...