[LJenkins1LE]

Originally Posted by Kmeleon

A quick question, I have Motul 660 in my SS 1LE since last fall. Going to Pocono this Thursday and then NJMP next Friday. These are the first two track days I'll have taken the car to on this fluid. Being that I'll just be getting up to speed this week I'm not quite sure I'd even need to bleed the brakes until the end of the season....

But how much fluid do you look to drain out of each bleeder when just bleeding between track days?

Is it really necessary to replace all brake fluid annually (flush) or is just bleeding every couple track days sufficient over the year to replace the fluid with new?

When I started tracking my 1LE I did a lot of research on brake fluid, and time, more so than use, was the most “detrimental“ to brake fluid. Use obviously decreases the amount of time the fluid remains optimal, but the longer it is in the system the more moisture it is allowed to absorb. I have found that brake fluid on cars with regular street use needs to be changed between (varied) 2-3 years so track use would reduce that time frame. I don’t use fluid from an open (unsealed) container so when I bleed I use the entire container of fluid. I bleed after every 3 events or 6 months. As I can’t find a reliable DIY way of testing for fluid moisture I came up with this bleed schedule. I use ATE Typ 200 in my system. It’s ~$18 per liter with a dry boiling point of 536 degrees. Since I bleed it so often it doesn’t kill the budget, and I figure that I will be using the fluid more towards its dry boiling point at the track.

This is just my opinion on brake fluid and what I do. Other people do different things that work for them also. I just wanted to post my process and thoughts on it.

[GTO_Gregory]

Originally Posted by metros11

How do they test for moisture content?

Check out Amazon for "brake fluid testers." There are several, but two different methods. Test strips and electronic.

1. Phoenix Systems 8006-B Double-Ended Coolant + Brake Fluid Test Strips. About $20.00.

2. eOUTIL Brake Fluid Tester Pen, Hydraulic Fluid/Liquid/Oil Moisture Analyzer with 5 LED Indicators, Auto Brake Diagnostic Testing Tool for DOT3 DOT4 Brake Fluid. About $10.00.

Electronic models range in price from $9.00 to $110.00.

[cmfhsu]

Originally Posted by LJenkins1LE

When I started tracking my 1LE I did a lot of research on brake fluid, and time, more so than use, was the most “detrimental“ to brake fluid. Use obviously decreases the amount of time the fluid remains optimal, but the longer it is in the system the more moisture it is allowed to absorb. I have found that brake fluid on cars with regular street use needs to be changed between (varied) 2-3 years so track use would reduce that time frame. I don’t use fluid from an open (unsealed) container so when I bleed I use the entire container of fluid. I bleed after every 3 events or 6 months. As I can’t find a reliable DIY way of testing for fluid moisture I came up with this bleed schedule. I use ATE Typ 200 in my system. It’s ~$18 per liter with a dry boiling point of 536 degrees. Since I bleed it so often it doesn’t kill the budget, and I figure that I will be using the fluid more towards its dry boiling point at the track.

This is just my opinion on brake fluid and what I do. Other people do different things that work for them also. I just wanted to post my process and thoughts on it.

I'll note that the only exception to this in my experience is getting the brakes hot enough to boil the fluid. Once I've put enough heat in my brakes to get a soft (relatively) pedal after coming off track, it takes that edge off the fluid that you get after a fresh flush. Still works fine for the next track days, but just doesn't have the really nice bite that fresh fluid has.

My Brembo stuff has a great quality of absorbing most of the gas back into it so I get a firm brake pedal again on my drive home, but it makes a bit of a noticeable difference. One quick bleed out of my calipers and it's all new again.