How much brake fluid is necessary to buy when switching to Castrol SRF?

[RSXDC5]

Hey everyone, I am preparing for my first trackday in my F80 and was curious how many bottles of Castrol SRF I will need. 1? 2? 3?

Only asking since it is pretty expensive per bottle, thanks in advance!

[M3 Number 86]

Buy 2 then you can do a full flush and have some left over in case you spill, mess up, and bleed.

[stranger]

I was wondering this.

How often would you need to change it?

[coolmody]

I used 2 bottles of Motul RBF660 (500mL) to do a flush. Couldn't really tell if it was a full flush as the color of the fluid was very similar to the stock fluid.

[MasterC17]

I used one.

[Groundpilot]

You will need two bottles. I recommend pressure bleeder and you need to do it once a year. No need to bleed brakes in between. SRF fluid is that good.

[afadeev]

Originally Posted by RSXDC5

Hey everyone, I am preparing for my first trackday in my F80 and was curious how many bottles of Castrol SRF I will need. 1? 2? 3?

Only asking since it is pretty expensive per bottle, thanks in advance!

If you buy 1, you will need 2.
I always buy 2, and need only 1 quart
You can store the other bottle until the next time.

Like other mentioned, using a pressure bleeder is of great help. Something like this:
http://www.turnermotorsport.com/p-28...pean-cars.aspx

If price point is a concern, you can always go with ATE TYP 200 fluid instead (marginally lower dry boiling point, significantly lower wet boiling point).

a

[CanAutM3]

Originally Posted by stranger

I was wondering this.

How often would you need to change it?

I would recommend flushing once a year at the beginning of the season.

Fresh fluid is more important that than the fluid itself. I have been using the OE fluid on all my ///Ms for the last 15 years with 16~20 track days per season without any issues. Going with SRF is an excellent precaution, but even with SRF, you still need to flush once a year as a minimum.

[CanAutM3]

Originally Posted by afadeev

You can store the other bottle until the next time.

Only if you don't open it.

If you do open it, it needs to go in the garbage.

[Gearhead999s]

Originally Posted by CanAutM3

I would recommend flushing once a year at the beginning of the season.

Fresh fluid is more important that than the fluid itself. I have been using the OE fluid on all my ///Ms for the last 15 years with 16~20 track days per season without any issues. Going with SRF is an excellent precaution, but even with SRF, you still need to flush once a year as a minimum.

I am also using the stock BMW fluid with no issues and I am known to be hard on brakes.The biggest thing is to make sure you do a proper cooldown of your brake system before stopping in the pits.I have found that usually when you have fluid issues if you do not do this or get forced by an on track red flag to sit with hot brakes.

[CanAutM3]

Originally Posted by Gearhead999s

I am also using the stock BMW fluid with no issues and I am known to be hard on brakes.The biggest thing is to make sure you do a proper cooldown of your brake system before stopping in the pits.I have found that usually when you have fluid issues if you do not do this or get forced by an on track red flag to sit with hot brakes.

Excellent point .

A proper cooldown is so fundamental to good brake management and helps all of the brake system's components.

[MaynardZed]

Yep, once a year or after anytime you boil your brake fluid. I boiled mine at a summer session earlier this year because I kept pushing when I was chasing / playing with my buddy. I "won" the DE session , but had to flush after that.

[stranger]

Originally Posted by CanAutM3

I would recommend flushing once a year at the beginning of the season.

Fresh fluid is more important that than the fluid itself. I have been using the OE fluid on all my ///Ms for the last 15 years with 16~20 track days per season without any issues. Going with SRF is an excellent precaution, but even with SRF, you still need to flush once a year as a minimum.

Thanks

How much fluid is required for a flush through?

I've been told I would need 2 litres as I plan to change to stainless steel brake hoses at the same time as Upgrading my fluid

[CanAutM3]

Originally Posted by stranger

Thanks

How much fluid is required for a flush through?

I've been told I would need 2 litres as I plan to change to stainless steel brake hoses at the same time as Upgrading my fluid

I have no clue how much fluid is needed as I have always had the dealer do it, so you will have to rely on others for that input.

Don't bother with the SS braided line, it is a waste of money. Both my E46 and E92 had no brake line issues after 100+ track day over 6~7 seasons each.

[MaynardZed]

Originally Posted by stranger

Thanks

How much fluid is required for a flush through?

I've been told I would need 2 litres as I plan to change to stainless steel brake hoses at the same time as Upgrading my fluid

Best to have 1.5-2 liters on hand but likely will only need 1 liter. SRF comes in 1 liter bottles, whereas many others come in 0.5 liter bottles BTW.

Stainless steel lines are generally used to improve pedal feel, not necessarily for reliability reasons. I usually add them as a matter of course, but agree on a new car like our F8X's probably not required.

[MaX PL]

I bought two .5L bottles of Endless RF650 in July and my mechanic had half a bottle left after a full flush.

I don't see why you'd need more than 1L of SRF.

[M3 Number 86]

Originally Posted by stranger

Thanks

How much fluid is required for a flush through?

I've been told I would need 2 litres as I plan to change to stainless steel brake hoses at the same time as Upgrading my fluid

Everyone said the same thing as the first response in this post. lol

After you use however much to flush (could be 1L could a little more than 1L to make sure sure), you can use that to bleed out bubbles.

This is the best fluid available but if you are chasing a ghost on the track they eventually will need a bleed as necessary.

[cays]

1L is plenty to thoroughly flush the system and to have a little left over to add as necessary. (Go to a store with camping supplies and get a small bottle for airtight storage). I've measured a few times and it takes less than 6oz for fresh fluid to reach the RR caliper so you can take it from there. If you replace the brake lines I'd suggest a gravity bleed first for the full fluid exchange and you'll want to have a rubber mallet around to tap the calipers to dislodge air bubbles as you go. That's about 3-4 hrs to do the four corners so it's a good weekend project while watching football games. Once that is done and buttoned up you can use a Motiv or equivalent for a second bleeding session if you have changed lines. That would make it an relatively more expensive (1.5L of fluid) procedure. Either way, pumping a little extra fluid through is well worth it to know the job was *perfect*.

[robbo mcs]

Originally Posted by CanAutM3

Only if you don't open it.

If you do open it, it needs to go in the garbage.

Not necessarily.

The reason castrol SRF is so good, and can last so long without bleeding etc is because the wet boiling point is so much higher than everything else on the market.

Most of the top end "race" products have pretty good dry boiling points. What separates SRF from others is that it's wet boiling point is much higher than anything else.

Once you open a bottle, or put fluid in your car, it immediately starts absorbing water from the environment, gradually becoming "wet". This will happen both in the sealed brake system of the car as well as an opened and resealed bottle. For most products this dramatically decreases the boiling point, meaning the fluid is much more prone to boiling.

So an opened bottle of SRF is not as good as new one, but is probably still not too bad.

[CanAutM3]

Originally Posted by robbo mcs

Not necessarily.

The reason castrol SRF is so good, and can last so long without bleeding etc is because the wet boiling point is so much higher than everything else on the market.

Most of the top end "race" products have pretty good dry boiling points. What separates SRF from others is that it's wet boiling point is much higher than anything else.

Once you open a bottle, or put fluid in your car, it immediately starts absorbing water from the environment, gradually becoming "wet". This will happen both in the sealed brake system of the car as well as an opened and resealed bottle. For most products this dramatically decreases the boiling point, meaning the fluid is much more prone to boiling.

So an opened bottle of SRF is not as good as new one, but is probably still not too bad.

I agree than you can keep the bottle for top-offs during the season. What I meant is that it is not a good idea to keep an open bottle to do a flush a year later.

[robbo mcs]

Originally Posted by CanAutM3

I agree than you can keep the bottle for top-offs during the season. What I meant is that it is not a good idea to keep an open bottle to do a flush a year later.

Yes, a new bottle is always required for a complete flush, not much point starting with aged fluid.

[Ghostriderf80]

Originally Posted by CanAutM3

I would recommend flushing once a year at the beginning of the season.

Fresh fluid is more important that than the fluid itself. I have been using the OE fluid on all my ///Ms for the last 15 years with 16~20 track days per season without any issues. Going with SRF is an excellent precaution, but even with SRF, you still need to flush once a year as a minimum.

M fluid boiled at the end of a straight, I thought I was going over the edge into the bush. Really OEM brake fluid?