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Brake Flush Question 1L or 2L using Castrol SRF

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What's up guys, quick question.

I just did a brake flush using Castrol SRF. I only used 1L of fluid, but purchased a second bottle to be safe. I know the capacity in our cars is 750ML, but I keep feeling like I should just suck it up and run the second bottle through. Any input on whether or not it's really necessary? Those that have done a flush what did you do?

My old OEM fluid was dirty, so it was easy to tell when the new fluid was in. I spent the majority of the time flushing the rear right until it was clear and then moved around the car and had enough to go around a second time.

BTW: What is the deal with Castrol SRF being out of stock everywhere the past several months? I picked mine up six months ago, otherwise I would've had to use Motul.

Thanks in advance,

Jeff
 
Which car do you have?
 
741
1,075
TX
I cooked RB600F at Thunderhill. Was pretty bummed about it. SRF has been solid and is definitely preferred.

In the same boat. Still trying to hunt down SRF.
 
I cooked RB600F at Thunderhill. Was pretty bummed about it. SRF has been solid and is definitely preferred.

In the same boat. Still trying to hunt down SRF.
How much fluid are you using on a flush? I just took the car out after my initial flush/pad swap. Pedal felt a little soft, but brakes were working fine on the bed in procedure. I’m not sure if the feel had to do with the pads being cold since they obviously require more heat to bite than a street pad. I had enough to go around the car twice with the initial 1L of fluid and had no bubbles, but again I’m second guessing myself.
 

Bill Pemberton

0ld Ford Automotive Racing Terror
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One question I always ask is how often do you change fluid? Over the years I have seen alot of guys running SRF change their fluid somewhat infrequently. It is great , but it is not the panacea for a ton fewer brake flushes. Had a friend complain about the Motul in his car earlier this year, and found he was on his third event since flushing and the previous one was towards the end of 2018. Guys, if you are aggressive. fluid needs to be changed quite frequently, and SRF is the best around , but don't rely on thinking it won't need changed hardly ever.

Just a comment in case you are relying on it and changing it infrequently.

Another note to the individual wondering about pedal feel, even with new pads after an active session it is likely your pedal feel will become different. Softer is not unusual , but when the pedal travel and pressure become markedly different , that is the time to be aware that your braking distances will likely increase and the system is heating up.
 

steveespo

Lord knows I'm a Voodoo Child
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One question I always ask is how often do you change fluid? Over the years I have seen alot of guys running SRF change their fluid somewhat infrequently. It is great , but it is not the panacea for a ton fewer brake flushes. Had a friend complain about the Motul in his car earlier this year, and found he was on his third event since flushing and the previous one was towards the end of 2018. Guys, if you are aggressive. fluid needs to be changed quite frequently, and SRF is the best around , but don't rely on thinking it won't need changed hardly ever.

Just a comment in case you are relying on it and changing it infrequently.

Another note to the individual wondering about pedal feel, even with new pads after an active session it is likely your pedal feel will become different. Softer is not unusual , but when the pedal travel and pressure become markedly different , that is the time to be aware that your braking distances will likely increase and the system is heating up.
Bill in reply to this, Castrol SRF can go a full season with just bleeds between events. It is much less hygroscopic than the other race or street DOT4 fluids, which is why the wet boiling point remains so high. My definition of a season is 19 HPDE/TT days over 11 events. Bleeds after each event, using maybe .25L. We run Pagid RST-3/RSL-29 pads and push the cars very hard on Hoosiers or take off slicks. The cost of SRF is well worth it. One bit of advice for those using it, Ford engineers have cautioned that it attacks the seals in the clutch system, therefore separating the clutch reservoir from the brake system and using the Ford DOT4 LV fluid specified for 2015-20 Mustangs is a good precaution.
 

TMSBOSS

Spending my pension on car parts and track fees.
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So, I am doing the right thinks.
I bleed between events. I used a catch bottle with a hose. This allows me to see the color of the fluid coming out of the bleeders. I am surprised by the darkened color, a light tea color, after a day or two on track
I separated the clutch and brakes a few years back because of the “Dust” in the clutch system. Now I run SRF in the brakes and a cheaper dot 4 in the clutch system.
As an added bonus. My wife is just so “Overjoyed” to come out to the shop and help bleed the brakes. That look on her face while walking to the shop is priceless. Lol
 

Bill Pemberton

0ld Ford Automotive Racing Terror
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Not disagreeing that SRF lasts longer, but I never made it anywhere near a full season , and I would caution folks against that long a time. Too many different tracks around the US and varying degrees of heat cycles. It is great stuff and I have used it, but I politely believe your time frame on usage is way too long.
 
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