How much fluid to completely flush entire brake system?

[GJarrett]

As the topic says.... how much brake fluid would I need to completely flush out all the old fluid with new?

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[DougS550]

As the topic says.... how much brake fluid would I need to completely flush out all the old fluid with new?

Since your not doing brake bleeds that often, I got two quarts of the DOT 4 LV fluid and power bled the system using the correct bleed order. Called it a day. Good luck

 

[skinnyb]

I used 2liters to power bleed mine with a Motive bleeder and had a bit leftover..

 

[SnowFox]

Interesting. Somehow in my life I escaped doing a full break bleas flush. I don't need ATM but might do one for the learnz

 

[Skye]

I'm thinking 3-4, 16 oz bottles. As much as 2 quarts., 1.5 liters, as a general guide from comments in threads and product listings.

There's some caveats with ^ that. We don't all have the same calipers, the same overall volume. Others might be replacing or upgrading calipers with their flush. The former, with more of a base system, might use less. The latter, with larger calipers all-around, more.

Attached are two threads I've studied; they each have several comments, tips and experiences.

https://www.mustang6g.com/forums/threads/changing-the-brake-fluid.193321/

https://www.mustang6g.com/forums/threads/brake-fluid-replacement-with-motive-system.148353/

 

[WItoTX]

Without knowing how much pad life you have left, 2 liters is a good rough estimate. Could be more if your pads are almost shot, or as little as a liter if they are new.

 

[TonyT930]

Without knowing how much pad life you have left, 2 liters is a good rough estimate. Could be more if your pads are almost shot, or as little as a liter if they are new.

Just remember not to fill it to full if you have worn pads. When you replace your pads and push the pistons back, you may over flow your brake fluid reservoir and cause a mess. And brake fluid is very corrosive. Sorry, I didn't mean to reference your specific post.

 

[GJarrett]

Thanks for the replies. I'm using Motul 600 which is already pretty good, but felt my brake pedal get a little spongy at the very end of my last session at Barber last weekend which is as hard as I've pushed the car on the track so far. Gonna upgrade to Castrol SRF for its superior wet boiling point and want to make sure it gets all the way to all the pads.

 

[Dana Pants]

Thanks for the replies. I'm using Motul 600 which is already pretty good, but felt my brake pedal get a little spongy at the very end of my last session at Barber last weekend which is as hard as I've pushed the car on the track so far. Gonna upgrade to Castrol SRF for its superior wet boiling point and want to make sure it gets all the way to all the pads.

I put 1 L of rbf600 through my system every spring. After 1L it’s pretty clearly peeing clean fluid. I let the brakes bleed into a measuring cup so I know how much I’m putting through each corner.

Realistically, hot pedal softness is probably a pad problem, not a fluid problem. I can cook my stop tech sport pads in a couple miles of track driving if I’m going for it. My car is 95% autocross, so I don’t have/use track specific pads.

 

[GJarrett]

I just upgraded from 340tw Firehawks to wider 200tw tires for the first time, and took it to Barber which has a lot of turns and heavy high speed braking.... I stressed my brakes more than ever before, and have GLoc R8 on front..... if it's pads, that will be the problem, I'll need to upgrade to R10 or R12. I've got a slower/lighter Ecoboost compared to a GT and was hoping I could get away with R8s.

 

[Dana Pants]

I just upgraded from 340tw Firehawks to wider 200tw tires for the first time, and took it to Barber which has a lot of turns and heavy high speed braking.... I stressed my brakes more than ever before, and have GLoc R8 on front..... if it's pads, that will be the problem, I'll need to upgrade to R10 or R12. I've got a slower/lighter Ecoboost compared to a GT and was hoping I could get away with R8s.

Which tires are you using? I track the 71rs, which dies just about as fast as my brakes.

 

[GJarrett]

I wanted all the HPDE track sessions I could get before they wear out, so went with an endurance 200, the Hankook R-S4. I nearly went with Conti Extreme Force but got a greal deal on the Hankooks.

 

[Dana Pants]

I wanted all the HPDE track sessions I could get before they wear out, so went with an endurance 200, the Hankook R-S4. I nearly went with Conti Extreme Force but got a greal deal on the Hankooks.

Endurance tires need endurance pads. The story fits.

 

[Garfy]

Just remember not to fill it to full if you have worn pads. When you replace your pads and push the pistons back, you may over flow your brake fluid reservoir and cause a mess. And brake fluid is very corrosive. Sorry, I didn't mean to reference your specific post.

Actually the level is irrelevant because when you replace the pads and push the pistons back into the caliper, you open the bleeder so the fluid is dumped out when you push the pistons back in. You do NOT want the old fluid to be forced back into the master cylinder as any debris and junk in the caliper would return to the master cylinder and possibly cause issues with the primary piston cups in the master. Always open the bleeder when pushing back the pistons so the old fluid in the caliper is not pushed back into the system.

 

[VictorH]

Thanks for the replies. I'm using Motul 600 which is already pretty good, but felt my brake pedal get a little spongy at the very end of my last session at Barber last weekend which is as hard as I've pushed the car on the track so far. Gonna upgrade to Castrol SRF for its superior wet boiling point and want to make sure it gets all the way to all the pads.

If you're having brake system trouble, best not to guess and use some brake temp paint.
https://www.opmustang.com/store/p42...ake_Rotor_Temperature_Indicating_Paint.html#/

I bet your NOT boiling your fluid but rather experiencing brake fade. You probably need better track pads. Also, Barber isn't really notorious for being hard on brakes. Maybe you don't have the Brembo 6-piston set up and running something more like the stock base calipers?

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