Castrol SRF brake fluid

Les · Feb 9, 2003

Would ya'll say that Castrol SRF brake fluid at close to $70 a liter is a little bit of overkill or is it worth it?
DOT 4 motor vehicle brake fluid suitable for use in all disc and
drum brake systems - wet boiling point of 270 deg. C (518 deg. F)

I looked in my 2002 Pontiac WS6 owners manual and it says to use Dot 3.

Thanks,
Les

tomq · Feb 9, 2003

ttt
i'm interested too
I bought it for my 2k1 trans am

RobZ71LM7 · Feb 9, 2003

Definately worth it! This fluid has the highest wet boiling point of any brake fluid and is servicible for one year under race conditions. In a daily driven car it'll last years. The extended life will actuaally make it cheaper than ATE and Motul in the long run. And yes it does provide good corrosion protection for street-driven cars. There is nothing wrong with using it in your trans am. I know of people using it in daily driven f-bodies and gm trucks.

[ February 09, 2003, 11:02 PM: Message edited by: RobZ71LM7 ]

OneQuartLow · Feb 9, 2003

Sounds like good stuff but how much do you really race? I'll vote overkill unless you do serious laps. If you haven't already upgraded rotors & pads those will be the weak points.

Any fluid can last for years unless parked with the reservoir open or with similar points of contamination.

David

RobZ71LM7 · Feb 9, 2003

quote:

Originally posted by OneQuartLow:

Any fluid can last for years unless parked with the reservoir open or with similar points of contamination.

Two years is typically the maximum time for any brake fluid-by then it's black. After a few months regular brake fluid is typically at or very close to it's wet boiling point which is below 300*F for a Dot 3. Today's systems are very porous due to polymer reservoirs and all the rubber lines which allow moisture to enter the system. That is why better brake fluids are sold in metal cans. Under normal conditions SRF can almost be considered a lifetime fluid.

OneQuartLow · Feb 9, 2003

Rob, sorry to differ but that isn't reality here in rainy Oregon. I've run hundreds of road laps with OTC DOT 4 and it was never a weak point. I've worked on dozens of 10 year old 100K+ street vehicles with factory brake fluid, perhaps with top-ups for service, and they stop like new with a good brake job using non-junk parts. (though I will change out fluid if doing it right)

I'm not saying old fluid is optimal, but adequate service life depends on the environment, the vehicle's purpose, and (honest) driving severity. I might use it with a NASCAR budget, but then Castrol would give it to me with mandatory stickers. For others that see track time, certainly with stock or mildly upgraded braking components, a better choice than $70/l and no maintenance is at least annual maintenance and any good DOT4 fluid. If running laps, there's no business leaving the system bottled up for a lifetime or even a few years with one fill of fluid. Water content will still hurt the components, especially when it settles during the off-season. I'd have it out at least yearly anyway for prep, upgrades & inspections.

IMO, the marketers are having a ball with this one. Remember, this is the company that brought us non-synthetic syntec, and made it stick.

Bror Jace · Feb 9, 2003

I used to use Castrol LMA ... which was their typical high performance brake fluid (DOT 4, I believe) but available everywhere for just a little more than the Prestone, etc ... (common brands).

Then Valvoline came out with Synpower which advertised slightly higher boiling points and I switched to that. They also had a 2-for-1 special going on at the time so I picked up a couple quarts for about $4 U.S. I still have one unopened (foil seal intact).

Anyway, I replaced my Civic's fluid in the fall of 1998 and the stuff is still fairly clear. I'm pretty amazed, but that's the way it's turned out. It is probably the color of Bass ale after 4+ years. If I was keeping the car, I'd do it again this coming spring and use up that remaining quart.

--- Bror Jace

John R · Feb 9, 2003

Les,

Castrol SRF is overkill for your application. Are you autocrossing? Do you do track events?Listen to OneQuartLow. He has actually done some track time.

From another forum:

"As I'm sure you must be aware, all conventional brake fluids are hygroscopic, that is, they absorb water from their surroundings.

However, being a silicon ester based fluid, Castrol SRF is actually less hygroscopic than conventional glycol ether borate ester brake fluids - it absorbs less water in a given period of time.

Additionally, unlike conventional fluids, Castrol SRF actually reacts chemically (through a patent-protected process) with the absorbed water to reduce its adverse effects, preventing the high-temperature wet performance from deteriorating as rapidly as it would otherwise."

SFR is good stuff no doubt, but no, Rob, Castrol SRF cannot be almost considered a "lifetime" fluid. Nor any fluid for that matter.

Ken2 · Feb 10, 2003

quote:

Originally posted by OneQuartLow:

....
I've worked on dozens of 10 year old 100K+ street vehicles with factory brake fluid, perhaps with top-ups for service, and they stop like new with a good brake job using non-junk parts. (though I will change out fluid if doing it right)

I'm not saying old fluid is optimal, but adequate service life depends on the environment, the vehicle's purpose, and (honest) driving severity.
....

Two occasions I know about when the brake fluid boiled--
All the papers had articles a couple of years back about a driver at Deception Pass St. Park who had his brakes fail while driving down a very steep park road. He hit a child at the bottom and killed him. It was reported that he'd recently had brake work done, the shop had installed steel pistons instead of the OEM plastic pistons, so much heat transferred to the fluid that it boiled. (I guess this guy didn't know to drive down hill in 1st. The Goodyear shop that did his brakes used parts spec'ed for his car from a good aftermarket source.)

A friend was towing his horse trailer down Mt. Adams. He's a careful driver, but his brake pedal went to the floor. He managed to stop using his trailer brakes and his parking brake, pulled over, changed his shorts, and looked his truck over. No broken brake hoses, no sign of leakage, brake fluid level was OK. By this time he tried again, and his brakes were OK. He came home very carefully, took his F150 to his mechanic, and the diagnosis was boiled brake fluid.

I change the brake fluid biennially or every two years, which ever comes first. I use Castrol LM GTA.

Ken

[ February 10, 2003, 10:18 PM: Message edited by: Ken2 ]

RobZ71LM7 · Feb 10, 2003

quote:

Originally posted by John R:
Les,

Castrol SRF is overkill for your application. Are you autocrossing? Do you do track events?Listen to OneQuartLow. He has actually done some track time.

From another forum:

"As I'm sure you must be aware, all conventional brake fluids are hygroscopic, that is, they absorb water from their surroundings.

However, being a silicon ester based fluid, Castrol SRF is actually less hygroscopic than conventional glycol ether borate ester brake fluids - it absorbs less water in a given period of time.

Additionally, unlike conventional fluids, Castrol SRF actually reacts chemically (through a patent-protected process) with the absorbed water to reduce its adverse effects, preventing the high-temperature wet performance from deteriorating as rapidly as it would otherwise."

SFR is good stuff no doubt, but no, Rob, Castrol SRF cannot be almost considered a "lifetime" fluid. Nor any fluid for that matter.

It certainly can be if you think 10 years is ok for plain off the shelf fluid.

When I said lifetime I meant several years-sorry for using bad terminology. If you don't value your brake system or your life then by all means run brake fluid for 10 years. I change regular fluid every two years minimum and SRF can go at least twice as long.

Castrol SRF is an exotic synthetic brake fluid (a silicon ester derivative) used in racinf conditions where brake take a beating. It has also been found to perform well in heavy duty applications (i.e., large trucks and tow vehicles) because it maintains it composition, wet/dry boiling points, and won't lead to brake fade under continuous hard braking. In fact, SRF is nothing like conventional fluids when it comes to moisture entering the system, which occurs no matter how good the system is maintained due to permeable rubber brake lines and gasket. SRF absorbs MUCH less water than other fluids out there, performance or not, and unlike ANY other fluid, the water it does absorb reacts chemically with SRF in a matter that does not degrade the fluid or lower the wet boiling point (the real factor for street brakes). On top of this, SRF has the absolute highest wet and dry boiling points out there at 518 degrees F and 590 degrees F, respectively. SRF is also compatiable with all brake systems and it exceeds DOT 3 and 4 standards.

What we really want to talk about are saturation points (quantity of water the fluid can absorb til it reaches it's limit). For example Valvoline Synpower Dot 4 fluid has nice BP's for it's price but it's saturation point is much lower than other off the shelf fluids-according to engineers I know. I've been told SRF has a saturation point of ~22%-can anyone confirm? Wet boiling points are tested after the brake fluid has absorbed 3.5% moisture.

[ February 10, 2003, 11:47 PM: Message edited by: RobZ71LM7 ]

outrun · Feb 11, 2003

I concur with those that differ.

Molekule can cite the chemical term for those things that tend to "suck" out atmospheric water and hydrate themselves.

This characteristic is the downfall of Brake fluids (DOT III and DOT 4) DOT 5 is a different stuff from silicone not intended for ABS Systems!

As far as the Castrol SRF excellent stuff...especially for your 1998+ Camaro's Firebirds with their MIGHTY stock PBR 2-piston/caliper front, 1piston/caliper rear Australian made calipers. If you have driven them GM did a good jobs on putting those fast stopping brakes on this car.

I would recommend changing the fluid every 1-2 years..2 being the absolute latest! Skank and crud do build up in the system as does atmospheric water...I am sorry but the brake resovoir/master cylinder is not "air-proof."

Changing your brake fluid at specific intervals with our with out brake service is good maintenence and cheap insurance.

My habit is if the brake linings get changed so does the fluid. Last year I switched to the Hawk HP Street Ferro-Carbon pads...they are much quieter, better stopping, and less dusting than the OEM pads. Plus, they are lasting much longer

Castrol SRF brake fluid

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