Feisty the "Family Car"

Got serious and finally did a brake (and clutch) flush with ATE200 brake fluid. Added stainless lines while I was at it. There's a slight difference, but very subtle and could just as well be the new fluid rather than the brake lines. Ran 2 whole liters of fluid through the system.

Ended up buying a power bleeder, and making 4 of my own brake bleeder bottles with 1/4" silicone tubing, some juice bottles from work, some cheap 1/4" PVDF check valves, and some silicone bottle clip rings I found on ebay, with a little wire to hang them. Ended up being a huge help since to do it right, you need to bleed with Forscan.

My neighbor gave me some surplus surgical drapes that I cut up and put to good use here to keep from spilling brake fluid everywhere.

Word for the wise, if you do a pretty thorough brake flush by cycling the ABS unit, hook the car battery on a charger. The ABS unit draws a ton of current, and if the accessory voltage Forscan is seeing drops below 10V, it aborts the test. I'm glad I had the check valves in the bleeders, as the last flush stopped in the middle!

Have you driven it hard enough on the street to get into the ABS or the other nannies yet?

I ask since I am wondering if the called for need of a DOT4 LV fluid is all just total BS or not, and I would prefer to use the Typ200 over even the great, also long lasting like the Ate claims to be (but lower wet and dry boiling points, of course), Bosch LV fluid I used for the last (and first for this car) full brake/clutch fluid flush (but not with the Forscan cycling activation though, as the self employed, individual mechanic I went to did not have that program at all ).

Of course, if you are going to do open track sessions you actually want all of the nannies as disabled as possible (yes, many of us even on the street want the same as well, it seems), so if the more viscous fluid somehow helps accomplish that by either defeating, or lessening them, all the better for that scenario.

Did you use the (factory manual suggested) reverse bleed flush method for the clutch, or a reservoir down flush method?

Did you use OEM windshield trim or aftermarket? The aftermarket ones say they are made of ABS, which is a hard plastic usually, not rubbery.

I did take the car out and give it a good run on Friday dropping my daughter off at a camp, and have not gotten the brakes to fade. However, I do *always* drive with the ESC off, (but with the Cobb TC in the tune that just pulls timing). On the street I’m usually barely tickling the ABS, and you don’t brake that hard if you’re at all in proximity to the speed limit, especially on good tires. The torque vectoring hasn’t been a problem thus far.

I did finally book a trackday at Laguna Seca for April. So we’ll see how the brakes do then.

Low viscosity fluid may be easier on the ABS unit at very cold temperatures. That said, brake fluid loses viscosity at temperature just like motor oil, so if you’re actually pushing hard (like on the track), LV fluid might actually get too thin.

The difference between “normal” and LV fluid is 1400 vs 700 mm^2/s at -40C. But by -20C, normal viscosity fluid will have already dropped below 700. Room temp viscosity is in the 5-10mm^2/sec range. Min at 100C is 1.5. Fancy “race” fluids maintain 3+ viscosity at 100C.

So unless it gets shockingly cold where you are, it’s not a big deal. If you’re worried about it, you can use any DOT4 SL6 fluid, or even a DOT 5.1 fluid (cold viscosity 900, or 750 for “5.1 ESP”). In California, I’d say it pretty much doesn’t matter.

Its hard to find viscosity plots vs temp, but I found one to illustrate how sharply viscosity drops.

Source: https://tanikawayuka.co.jp/eng/advance/brakefluid/

Also - specs for various DOT fluids: https://wiki.anton-paar.com/us-en/automotive-brake-fluids/