[artey34]

I swapped to Castrol SRF last year. I have 3 full track days and about 4k miles on it. I believe I read somewhere that it needs to be changed yearly due to water absorbtion? Do I just need to bleed them and flush 1 new bottle in? Or do a full flush and fill?

This is what I use
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

[TRZ06]

I'm no expert by any means, but unless you feel a difference in the pedal feel, I would leave it alone.

As the fluid collects moisture it will increase the spongy feel, if it feels as solid as when you added it, I would call it good.

On the other hand, if you are tracking, it's relatively cheap insurance to know the brakes will be there when you are going over 100.

[TrackClub]

I would give SRF a full year with one bleed mid year.

[TheRealJA105]

I switched to SRF before the beginning of this season and I don't plan on doing a full flush ever again. I just do small bleeds every couple of track days or if it feels spongy. The wet boiling point of SRF is only 90F below its dry boiling point, which brake fluid is only at before it is opened the first time.

[TrackClub]

ya but the issue is that high po fluids absorb moisture MUCH faster than regular OEM fluids which frankly folks don't change ever So as much as a high po fluid will resist boiling at much higher temps, its life span is much shorter and usually not recommended beyond 12 months after it has been poured from a sealed bottle. i have a good write up about this somewhere...lets see if i can find it...

[TRZ06]

Originally Posted by TrackClub

ya but the issue is that high po fluids absorb moisture MUCH faster than regular OEM fluids which frankly folks don't change ever So as much as a high po fluid will resist boiling at much higher temps, its life span is much shorter and usually not recommended beyond 12 months after it has been poured from a sealed bottle. i have a good write up about this somewhere...lets see if i can find it...

In general, you are correct. HOWEVER I think it has been proven that Castrol SRF does a much better job of not absorbing moisture as much as cheaper Dot 4 fluid.

I changed mine out 2 mths ago (about 10 mths total time with SRF) because the reservoir was showing less full and I honestly think I wasted my money on a full SRF flush instead of just topping it off. My pedal feel did not change one bit and is still as solid as the day I first swapped out the stock stuff.

[TrackClub]

Originally Posted by TRZ06

In general, you are correct. HOWEVER I think it has been proven that Castrol SRF does a much better job of not absorbing moisture as much as cheaper Dot 4 fluid.

I changed mine out 2 mths ago (about 10 mths total time with SRF) because the reservoir was showing less full and I honestly think I wasted my money on a full SRF flush instead of just topping it off. My pedal feel did not change one bit and is still as solid as the day I first swapped out the stock stuff.

You may be completely correct. But from my experience of having boiled (non SRF) fluid a few times, there is no prior warning, as the fluid is either boiled and the pedal goes to the floor, or it isnt and the pedal feels fine (even if it about to boil).

$100 bucks is about 0.5% of my track budget for the season and I'd seriously kick my own ass if i wrecked because i wanted to save such minimal amount on a key safety component. But that's me

PS what may also make a difference is what weather we run our cars in, humidity wise.