Track Day Braking/Boiling

Wabbitkilla · February 9, 2015, 07:41

So you aren't going to replace the old rubber brake lines for better stainless braided ones then? The difference is very apparent when you do.

Jrichards20 · February 9, 2015, 10:23

I did a couple of track days in my first stock car, I think all braking was stock, and brakes held up fine, pads wore out rather quickly though, full day of open pitlane will do that on half wore stock pads. Changed them rather quickly after for some harder wearing ones, but the brakes on the MR2 i found were very good stock. It is a light car without an engine over the front wheels so over heating brakes shouldn't be too much of an issue unless you are running additional power or have substantial additional weight.

Anonymous · February 9, 2015, 10:45

I must admit I haven't ever had problems with brakes on the mr2 on track. I've got them very very hot and never had fade or boiling fluid.

I run a hi temp fluid, braided lines and EBC green / yellow stuff pads

gaffer1986 · February 11, 2015, 20:15

I think it was because the first track day I did was with 10 year old brake fluid and they haven't been bleed well enough since then. However I seem to have firm up the brakes by doing a series of emergency stops from 30 mph. Can't understand why it worked. I have to say the brakes have been awesome, just the pedal goes spongy.

gaffer1986 · February 21, 2015, 21:01

I'm pretty sure my rear calipers are sticking which is causing the brake fluid to boil. What is a good sign that they are sticking? I've found that if I let go of the brakes just before stopping the car still seems to be braking ever so slightly, I mean a tiny amount. I'm assuming it's the rears because they are the ones that smoke and the rear calipers seem problematic on this car.

When I sell my VX220 I'm going to spend a bit of money on the brakes and replace the calipers completely, may get the braided hoses fitted also with new rear brake pads and brake fluid.

Not sure whether I should change the rear brake discs? They are standard but only 6 months old, is it worth replace the discs and the pads after a sticking brake caliper?

mikey P · February 21, 2015, 21:41

Jack rear of car take hand brake off, try and turn wheels (apply handbrake on and off a few times see how this effects things). My car needed the handbrake resetting and was fine after that.

ChrisGB · February 21, 2015, 21:53

To diagnose a sticking calliper, just drive it normally and very lightly on the brakes for a mile or two. Any calliper that is sticking will make the disc on that corner hotter than the rest.

GT4-Play · February 21, 2015, 23:21

Motul RBF600 and decent pads will go a long way to help.
Ultimately bigger thicker discs will be needed if your really pressing on and late braking etc.

gaffer1986 · February 25, 2015, 17:02

Thanks for the advice, I only just noticed your replies as I hadn't realised there was another page. I might give the blue brake fluid a go first as it's easier to tell when you have bled them.

gaffer1986 · February 25, 2015, 17:03

I will need to buy a thermometer

ChrisGB · February 25, 2015, 17:54

Quote from: "gaffer1986"I will need to buy a thermometer

It will be the sort of difference you will be able to feel by holding your hand near each disc. Don't touch the discs, they will be hot enough to cause burns.

gaffer1986 · February 25, 2015, 21:18

Well in that case I can see and smell the difference the NSR disc smokes after two laps at Snetterton followed by a spongy pedal. The OSR smells of brake but no smoke and the both the fronts neither smell or smoke.

I made the mistake of putting my finger through the hole of a mk4 escort's steel wheel when I was a boy to touch the shiny metal thing I could see. This was after a long drive and I will say it hurt, haven't touched a hot brake disc since s:D

s:D

Jrichards20 · February 26, 2015, 12:42

If the rear smokes and the fronts are fine you have problems on the rear! I would not be driving that on the track again until that is fixed. The fronts should be hotter than the rear. Get that looked at ASAP, no amount of brake fluid, bigger discs or braided hoses will cure that problem.

Anonymous · February 26, 2015, 12:52

Sounds like sticking calipers to me

gaffer1986 · February 26, 2015, 12:59

Yeah, definitely not doing another track day until it's sorted. What amazes me is that depsite the car having sticking calipers and leaking shock, it still drives spot on, well better than a VX220 which I hate and am trying to sell. So much more grip and braking ability from the MR2.

Jrichards20 · February 26, 2015, 14:50

The brakes on the MR2 to me were by far the most astonishing part of the car. Even stock they are very very good brakes.

1979scotte · February 26, 2015, 15:32

Quote from: "Jrichards20"The brakes on the MR2 to me were by far the most astonishing part of the car. Even stock they are very very good brakes.

Shame about the handbrake.

Anonymous · February 26, 2015, 16:26

Quote from: "1979scotte"
Quote from: "Jrichards20"The brakes on the MR2 to me were by far the most astonishing part of the car. Even stock they are very very good brakes.

Shame about the handbrake.

Haha, too true

Wabbitkilla · February 27, 2015, 07:35

This is worth a read.... m http://oppositelock.jalopnik.com/brake- ... 1688020147 m

Anonymous · February 27, 2015, 09:40

Nice info thanks for sharing.

Jrichards20 · February 27, 2015, 10:18

Interesting read, but I am not sure his logic of comparing a Formula 1 cars brakes to a cars brakes. F1 teams spend millions of pounds creating the perfect aerodynamics, and included in the aerodynamics is the cooling of the brakes. This is shown in races where a car is stuck behind another car and the brakes will heat up because it is not getting the normal airflow that it would be getting. So comparing F1 brakes saying that they don't have grooved/drilled/dimpled discs so therefore it basically means grooved/drilled/dimpled discs are not beneficial in cars is a bit silly.

Wabbitkilla · February 27, 2015, 10:50

Yeah, I think we have to remember there is another factor involved ...... brake materials.
He has talked about pad materials but some of the biggest advances have been in disc material.

So road car brakes will be a generation or three behind F1 brakes depending on the price you pay for the car, so ceramic or carbon discs are not that common.
What is clear is cheap components are not going to perform as well as quality priced components, in my mind brake discs from eBay comes to mind.

Jrichards20 · February 27, 2015, 11:17

Yes material is a huge factor but also how frequently does F1 change their brakes and perform a service on their car compared to a road car. But the good advice is about the quality. And the brake discs from eBay is certainly an item that I wouldn't be buying, there was an article on PH where I a relatively known seller was just buying normal brake discs and drilling his own holes in them and selling them for more. I would not want to do an emergency stop with those brake discs, never mind a track day.

gaffer1986 · March 4, 2015, 16:07

Does anyone know if the rear brake calipers are different on the 5 speed and 6 speed cars. Camskil offers different calipers but there is a rebuild kit on ebay that doesn't differentiate for different gear boxes.

m http://www.ebay.co.uk/itm/TOYOTA-MR2-1- ... 1366912327 m

gaffer1986 · March 4, 2015, 16:11

There is this rebuild kit also which is a bit of a bargain, has anyone tried it?

m http://www.ebay.co.uk/itm/Toyota-MR-2-1 ... 4878ecc24a m