VIR Track Day and Brakes

[FiatMac]

I ran my first track day with my 2000 Spider last week at the FLU sponsored Phil Wicks Driving Academy at VIR. I had a blast and may now be hooked!

The field was dominated by 500s and Abarth 500s. Of the 67 cars, there were 24 non-Fiats. Of the remaining 43 cars, there were fourteen Abarths, nine 500s, one 128, seven X1/9s, and 7 124/2000 Spiders.

Because I had never driven on a track before, I was put in the Novice group. The Novice group was made up of five Abarths, five 500s, two X19s, two Alfas, and three 124/2000 Spiders. I passed a lot of cars and was not passed by anyone. There were only a few laps were I got to run flat out for the entire lap. I would have liked to have tested my skills against the Intermediate group.

The one timed Solo lap that I got to run sucked...the transmission jumped out of gear (stupid me was resting my hand on the gear shift at the start) not once but twice on the start, and that got me a little flustered from the get go. That probably cost me 5 seconds.

Anyway I have a brake question.

I installed Ferado high performance (street/autocross) brake pads before the event and bedded them in. The pads performed very well with no evidence of fade. However, I did notice as the event went on that the brake pedal travel increased. At the start of the day the brake applied pedal height was about even with or slightly above the accelerator pedal. By the end of the day the pedal height on application of the brakes was below the level of the accelerator pedal making heel and toe somewhat awkward. However, the pedal was still firm and brake performance was good. The brake height has remained at this level. It does not increase with pumping and the pedal is firm, so I don’t believe I have air/vapor in the lines, but I will go ahead and bleed the brakes anyway.

Any other ideas as to what could be causing this?

[kmead]

Likely brake pad wear. You would be amazed how much pad you can eat up in one day of track driving, especially if you drive it hard. That things haven't changed since the event points to it not being compressible air in the lines.

Personally I would change the fluid completely and inspect the pads.

Karl

[FiatMac]

Karl,
The hydraulic system should adjust for pad wear since additional fluid is able to flow into the master cylinder from the reservoir when the brake is released. Therefore, pad wear should not affect brake pedal height.

[Fi8spider]

Same happened to me when I first started tracking my Spider.

Since changing the brake fluid over to AP600 (which is about a Dot 6 i understand) my brake pedal has remained firm all day long. Not cheap but well worth it.
http://www.ebay.com.au/itm/ALLSTAR-ALL7 ... 231aebbe45

Excessive heat is your enemy when it comes to brakes.

I have since changed my flexible brake lines to braided and have installed some flexible ducting to the rear calipers to keep them cool. Getting cold air to the front calipers has been a bit of a challenge as it is difficult to run ducting without it getting in the way of steering component travel and crushing the duct.

On a recent track meet I saw a Fiat with the front edge of the brake backing shield flared out so it catches air and directs it to the general area you want to keep cool. I will be doing the same.

[Daniel]

I saw a Fiat with the front edge of the brake backing shield flared out so it catches air and directs it to the general area you want to keep cool

thats a great ideal

[FiatMac]

Since changing the brake fluid over to AP600 (which is about a Dot 6 i understand) my brake pedal has remained firm all day long.

.
I will give the AP600 a try. However, my brake pedal seemed firm throughout the entire day, and seems firm today.

Thinking about it though, a small bubble could affect pedal height without affecting the feel of the pedal significantly. When I change out the fluid and bleed the brakes we will see what happens.

Excessive heat is your enemy when it comes to brakes.

Agreed

I have since changed my flexible brake lines to braided ...

My flexible brake lines are braided too, and that does make a difference!

On a recent track meet I saw a Fiat with the front edge of the brake backing shield flared out so it catches air and directs it to the general area you want to keep cool. I will be doing the same.

Sounds like a good idea.

Thanks for the input.

[Fi8spider]

Thinking about it though, a small bubble could affect pedal height without affecting the feel of the pedal significantly. When I change out the fluid and bleed the brakes we will see what happens.

I think you're on the money with the air bubble(s).
I try and do mine before each race meet just to keep a little bit of fresh fluid in the system and to ensure all air is out. Bleeding the caliper the furthest away from the BMCyl first (or with the longest run of pipe) and working my way closer.

I made up my own DIY brake bleeding bottle and hose kit so I don't have to ask anyone to help pump the brakes whenever it needs to be done. There are heaps of DIY brake bleeding videos and kits on the net.