Marshall Mosty
AI/SI Texas Regional Director
2011 NASA-TX American Iron Champ
AI #67 "Mosty Brothers' Racing" (RIP)
ST6 #21 Toyota Corolla (being revived)...
You flush the brake system every other round? Like, 3 or so times per season?? Are you having pedal problems? Typically, I flush the system at the start of the season, and don't flush it again unless I open it up (change a line, change a caliper, etc).
After PST did a moisture test on the ATE stuff at MSR-C in mid-2006, I realized I was over-flushing the system. The fluid they tested had been in the car a full year, possibly longer, and AJ was shocked that it was in such good condition. That told me everything I needed to know.
Other than moisture, what can happen to brake fluid? Does it wear out like motor oil? Does it get too dirty?
When I bought a set of Carbotech pads for my Mustang they talked me into Castrol SRF. The wet boiling point is so high that I don't really worry about moisture. Is there something else?
-Wayne
-CMC #85
Two seperate points:Point 1: Some mfrs have started to drop brake fluid change from their maintenance schedules, presumably because the fluids today far exceed what will be needed during the warranty period (and they better be right because the damages awarded in law suits involving brakes have been huge!).Point 2:Even well constructed brake systems running poly ether fluids will get contaminated (ambient atmosphere just as often as running in the rain, or abuse) and DOT 4 (including many high performance fluids) actually drop their wet boiling point faster than DOT 3 (sometimes twice as fast) so that with only 1% contamination the boling point can drop as much as a quarter and by half with 3% contamination. So the question IMO is how fast is the contamination occuring.I worked for a company that specialized in extreme use fluids, particularly lubricants (motor and gear oils, etc.) and I spent many a lunch time conversation with the head chemist and VP of R&D...can't remember half of what they told me, but I do remember the conversations about unavoidable contamination of systems using hydroscopic fluids (seals, lines, etc) and that systems should be bled after each extreme use cycle (e.g. after every race weekend) and generally flushed once a year for even well maintained equipment and every time the system is "opened".We did work for the large industrials (Herman the German ring a bell?), DoD, the Bodine's and a Baha race team as well as others so they knew their stuff.Moral to the story...I bleed after every race weekend and flush once a year - I stand on my brakes pretty hard.
I used the same SRF in my CMC car from the start of the 2005 season thru the April 2010 TWS event. I had to replace a master there on Friday and I flushed the system then. Before that, I would just bleed about 4" of fluid up a 1/4" clear hose to check the color and look for air bubbles.
Water is the enemy. Any oxygen in the system will boil out causing air pockets. H2O .........
Just another data point....
I use the Wilwood 570...( I have been told this is the same fluid as the old Ford HD that I used to use).
I change it twice a year also. At the first of the year and before Hallett. Then just a good bleed before ECR.
This stuff has been rock solid...never a soft pedal, not even after 40 minutes at Hallett.
Based on past brake performance, my new flushing schedule is once before Hallett and once before ECR. I'm also going to try running some ducts to the rear brakes, since it feels like that's where most of the brake fade is coming from.
I like Marshall's idea of switching between amber and blue, makes it easier to know when you're done
Eddie Rock
#21 AI '96 GT
Price points were higher than what I would expect to pay but the results seem to be what I'd expect - except the EBC blue did not do as well as I'd expected though
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