Brake fade at the track

[Christien]

I know brake fade and pad opinions have been discussed ad nauseum around here, but I'm not finding much pertaining to earlier cars.

At Mosport this weekend I noticed significant softness in my brakes, and not just towards the end of the day. I was getting it by my 3rd run of the day, even towards the end of my 2nd run. Should I be looking to upgrade pads, or is it most likely a fluid thing?

Here's what's there now:
Brand new MC (replaced last year)
Brake fluid changed at the same time (this was my 2nd track event since changing, wanted to change before this one but simply ran out of time, brake fluid is DOT4)
Textar brake pads
Aluminum S calipers up front, steels in the back, I'm assuming they're the original calipers, no idea if they've ever been rebuilt.
Engine is stock 2.4T, and probably not running at full potential (could use a tune-up). Speeds along the back straight at Mosport reached maybe 150-160km/h (95-100 mph) with a tailwind

Braking on the street is more than adequate, but probably could be stronger. I can lock the wheels, but have a very difficult time getting the tires to chirp under threshold braking (I've done it in other cars with no problem, so I'm familiar with the technique). I want to do the next DE in early June, but need to get this addressed first.

Thanks!
Chris

[Dantilla]

Were the pads properly broken in?

[s2per]

Change your brake fluid every time before a track event, or at the very least bleed the heck out of them.

Consider going to a track-oriented pad. I'm using Porterfield R4S (I believe); very stable on the track, great around town, no squeal.

Finally, get some air to the rotors. At the very least, remove your dust shields or invest in a Cool Brake kit.

[Jims5543]

I bleed my brakes between sessions sometimes, especially if I feel any softness in the pedal. This is a normal routine for me especially if I had a really good session and was pushing hard. Usually after about 60 minutes of track time.

I am using Hawk Blacks and Motul 600.

Also, how are you braking? Really hard and short or softer and longer?

You will over heat the brakes more if you are using them softly.

Try shortening your braking distance, the longer your foot is on the brake pedal the hotter everything is getting.

[Christien]

Yes. Sorry, should've mentioned that. They were replaced when the new MC/brake fluid was done. I checked them before I had the tech inspection done and there was lots of pad left.

[Jim Smolka]

First things to try:

1. ATE Blue or similar brake fluid
2. Hawk Blue race pads or similar
3. Brake Ducts (see tech article)
4. Rebuild Calipers

Next.

1. Consider larger MC.
2. Larger Brakes up front

One of the main reasons I like larger brakes up front is increased pad life. A friend goes through a set of pads in 1 to 2 weekends on his F-Class stock Carrera. Where as the large (4 piston) Wilwood pads can last a couple of years.

[Eric P]

Brake fade or soft brakes? Maybe a little bit of a difference between the two. Fade (meaning, loss of braking) may mean they are getting hot (need better pads, more air, poor break in, etc.). Do yo do a lot of breaking, left foot, etc.?

Soft (squishy pedal) breaks may be a fluid, air in lines, caliper issue. What kind of brake lines do you have?

[Eric P]

FYI: I have a '71 E (which I race) with the same caliper setup you have. They are fine. Good fluid, pads, and brake lines should leave you with fine braking. Ducting is a plus if they are really getting too hot. I don't know that a bigger MC would be much if any help.

[Christien]

Thanks for all the responses, guys. I should make it clear that I'm not racing - I'm still in the green run group, having now done only 3 DEs (and 2 were only 1 full track day due to IDS and weather, so really only the equivalent of 2 weekends). I'm not looking to improve performance, I'm thinking more safety-wise. I don't want to put a whole bunch of performance stuff into this car, because I'm not sure how much tracking I'm going to do with it. (may use a different car, not quitting DEs!)

I'm definitely going to replace the brake fluid and upgrade the pads before the next session.

Where do you find ATE Blue brake fluid? Never seen it in the local autoparts store - is it a special order type thing?

What's a good pad for track driving like I'm doing? (Rookie, less powerful car) I don't care about brake dust or noise, because I'll swap them out for the street pads when not at the track (car is a somewhat daily driver as well). I also don't want to break the bank with $400 worth of brake pads!

Thanks!
Chris

[Jim Smolka]

ATE Blue is available from our host. Great stuff. I like Hawk HP Blue race pads for the track. Yes, they are about $120 an axle.

[tonythetarga]

sending you a PM for a local contact.

[304065]

What you do not say is what wheels and tires, which are a critical part of the analysis.

Sell the aluminum calipers and buy NEW steel "A" calipers from our host. The braking improvement is more than worth the tradeoff in unsprung weight.

If you like bleeding brakes use ATE blue. I recommend Castrol SRF at $80/liter, it's not cheap, but you only change it once a year (to prevent rust in the brake system) because it has a 518F WET boiling point.

Once you leave the S brakes behind with their 19mm pad requirement you can use good old PF97 which are about half the price of Pagids and work better.

[Christien]

John, thanks for that suggestion - I actually thought the S calipers were the upgrade?!

FTR wheels are Fuchs (genuine) from an SC or Carrera, tires are Pirelli P6000s.

[Eric P]

Looks like I missed some tech info here. John, why can't PF97s be used with S calipers?

[tonythetarga]

Christien, your email box was full. You could try Ernie at Mantis racing in Mississauga for pads and fluid or also try a number of suppliers that advertise in Pano if what you want isn't available right here at Pelican.

[Christien]

Tony, sorry about that. Thanks for those sources. I usually take the car to Mantis when it needs shop work, so I'll ask them. Usually cheaper to order from pelican, though.

[Craig 930 RS]

Porterfield R4S are a *street only* pad - don't use them for track use! R4 is for track.

Bottom line is:

You are boiling the fluid. Brake system heat capacity isn't up to snuff, ie fluid old or not at a high enough boiling point, brake cooling, or sometimes (yet rarely) the braking system itself is not robust enough to handle the heat.

If you were my customer I'd say:

*Motul or ATE Blue
*Get as much cooling as possible
*Get some decent pads - Pagid or Performance Friction.
Many, many people absolutely hate Hawks and have had trouble with them. I will never recommend or carry them for this reason.

Changing to steel calipers will not cure your issue one bit.

My 2 cents based on 3 1/2 years of brake biz -

[bdonally]

Christien:
I assume you were at the DE event last weekend on the Mosport main track.
From your description, I think you were overheating the pads.
As mentioned in another reply, it is likely that you are over-using the brakes, and as you start carrying more speed through the corners you will have a bit less problem.
I have found that Mosport is not as hard on brakes as Shannonville.
Always pay attention to fluid, as mentioned, but I think that if you use either a track pad (Hawk blue, for instance) or a high performance pad (like Hawk HP+) I think you will find you are fine until you get out of the green run group.
I know Mantis can supply Hawk; they probably have other recommendations.
Don't use the Hawk Blues on the street - when they are cold they are an effective cutting tool and will go thorough rotors very quickly, as well as being very noisy.
You are going to blow through the $400 barrier pretty quickly, though.

[zotman72]

If you still have your original rubber brake lines, replace them right away as they have outlived their effective life, they swell with age and restrict the line. Brake cooling is important as well. The cooling kits (scoops, hoses and blockoff plates) are on sale now at AJUSA but I am sure our host will match their prices as they have in the past. Definitely go with high temperature brake fluid. I went with A calipers on my T as the S calipers really do not hold up as well on brake intensive tracks. Performance Friction Golds are what I use on my T, easier on rotors than the Hawk Blues. Be aware, tracking your car will set you up for a slippery slope of expensive improvements.HTH

[Eric P]

Zotman is right. Put on new brake lines and the right fluid then do not read this anymore. Otherwise, get out your wallet.