First, it's been a long time since I have been here. My bad and "HI" to all. Now on to my question. I'm doing a brake fluid exchange ointment my 2016 GT4 and, having had a bad experience once with corroded fluid, prefer for safety to use the "dry" method in which the Motive only pressurizes the reservoir, it does not push fluid in. The fluid comes from the reservoir and must be topped up periodically. It's that period I'm trying to ascertain. In my 986s there is a large space above the "MIN" mark - close to 400mL I would estimate,. In thge 981 not so, the MIN mark is very near the top (or appears so). How low can I go without danger of introducing air. It will obviously be full when I am done. TIA, Granthttps://pedrosboard.com/read.php?7,57206,57206#msg-57206Wed, 10 Jun 2026 10:57:42 -0400 Phorum 5.2.23 https://pedrosboard.com/read.php?7,57206,57216#msg-57216 https://pedrosboard.com/read.php?7,57206,57216#msg-57216
If you fill the reservoir to the top (above the max line) and bleed down to at or near the min line you should be able to bleed the whole system with only one top off.]]> Boxsterra Main ForumThu, 12 Jun 2025 09:41:59 -0400 https://pedrosboard.com/read.php?7,57206,57211#msg-57211 https://pedrosboard.com/read.php?7,57206,57211#msg-57211
All was well. I change my fluid with 600/660 every year. (have to as you know0.

I have never even come close to(from feel) to a soft brake pedal.

Changed fluid before. trip to WGI. Used wet method. After a couple laps pedal got soft nd within a lap went to the floor before turn 1. A pump or 3 got me safely through, but this was absolutely fresh brake fluid. I had done ~ 6 track days on the old (newly 9 months) (but bled) fluid with never an issue.

Repeated bleedings on site did nothing

Came home, ran 2 liters of cheap-O fluid through the system to clean it out; put in new 660. problem solved.

Was it contamination from water in the motive's line?Maybe. Some other contaminant? Maybe.
But it made me very cautious.

In a wet environment condensation can wreck havoc. In the bottle it invisible. In the one (in my case a replaced motive hose, which is I believe fuel line and opaque) it is not.

Grant]]> grant Main ForumWed, 04 Jun 2025 11:41:02 -0400 https://pedrosboard.com/read.php?7,57206,57210#msg-57210 https://pedrosboard.com/read.php?7,57206,57210#msg-57210It is so thirsty, that it will pull water molecules from the air through the brake likes themselves.
So, many times people think they had contamination from an external source, when they didn't.
That is the reason brake fluid in our cars needs to be flushed every 2 year regardless of miles driven.
Happy Boxstering,
Pedro]]> Pedro (Odessa, FL) Main ForumTue, 03 Jun 2025 16:40:19 -0400 https://pedrosboard.com/read.php?7,57206,57209#msg-57209 https://pedrosboard.com/read.php?7,57206,57209#msg-57209
Thanks, I do agree with all the downsides you list, they jsut pale compared to what occurred to me once. Entering WGI turn 1 with no brakes is not fun.]]> grant Main ForumTue, 03 Jun 2025 08:39:41 -0400 https://pedrosboard.com/read.php?7,57206,57208#msg-57208 https://pedrosboard.com/read.php?7,57206,57208#msg-57208
But, why?
I don't understand the "dry" approach.
It introduces the chance of drawing air that won't be visible.
It also exposes the new fluid to more opportunity to draw in humidity and chances to spill fluid outside the reservoir.
Happy Boxstering,
Pedro]]> Pedro (Odessa, FL) Main ForumSun, 01 Jun 2025 10:49:49 -0400 https://pedrosboard.com/read.php?7,57206,57207#msg-57207 https://pedrosboard.com/read.php?7,57206,57207#msg-57207
Grant]]> grant Main ForumFri, 30 May 2025 16:00:16 -0400 https://pedrosboard.com/read.php?7,57206,57206#msg-57206 https://pedrosboard.com/read.php?7,57206,57206#msg-57206
Now on to my question. I'm doing a brake fluid exchange ointment my 2016 GT4 and, having had a bad experience once with corroded fluid, prefer for safety to use the "dry" method in which the Motive only pressurizes the reservoir, it does not push fluid in. The fluid comes from the reservoir and must be topped up periodically.

It's that period I'm trying to ascertain. In my 986s there is a large space above the "MIN" mark - close to 400mL I would estimate,. In thge 981 not so, the MIN mark is very near the top (or appears so).

How low can I go without danger of introducing air. It will obviously be full when I am done.

TIA,

Grant]]> grant Main ForumFri, 30 May 2025 09:33:43 -0400