Bleeding Brakes?

[LouG]

I am thinking along the same lines. I don’t see how you could possibly get air bubbles in the fluid at the calipers, which is the most likely place for them, out by actuating the ABS module. The brake system is not a loop where fluid cycles through it; that is the whole reason the brakes work. You push the fluid and it has nowhere to go but to compress the caliper piston. Without opening a bleeder screw and forcing fluid (or air) in or out, I don’t get how the fluid in the caliper is going to get back to the ABS module.

Getting air out of the lines between the reservoir and the ABS module I could see working by actuating the ABS, but I don’t see that working for forcing air in the lines out of the entire system, which is the whole point of a brake bleed.

I agree. I've seen bleeding done by forcing fluid back into the reservoir. But never heard of circulating air bubbles around the system.

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[Neggytive]

The new caliper should already be retracted, so you can pop the existing one off without going into service mode as you don't need to retract the caliper to put new pads in

BUT that is the wrong way to do it as you should be installing new pads on the other side at the same time IMHO so you need to get the other side into service mode.

When you are ready to remove the hydraulic line have a tire valve stem ready and when the hose comes off jam the valve stem in the hose end to seal the line. That will keep you from having to bleed the ABS pump IMHO

When you put the new caliper on and get the hose on with new washers and torqued, put a pan under the caliper and crack the bleeder and let gravity bleed them. It is easier than pumping the crap out of the pedal and and it works. Let is drip while you are doing the other side, just watch the fluid level in the master.

I rarely ever have to do a 2 man bleed operation or get the Mit-Y-Vac out, Gravity bleeding is how we do it on our shop

 

[rustedrotors]

I'd also put as much fluid as you can in the reservior and close the cap. Have the new caliper ready and swap quickly.

ABS purge procedure is common in new cars/trucks. Really only an issue if you run out of fluid, or get air back in the line. Like pushing the caliper piston in without it being bled out.

IF you do get air into the ABS, you will need to run the bleed / purge sequence. And you might have some air back at the calipers to bleed out after that too.

 

[timd38]

I put Baer rotors on my DH and if you remove any of the rear calipers without putting the brakes in service mode, the dash lights up like a Christmas tree. I learned from someone else’s mistake.

 

[thornclaw]

not to plug third party software, but the iphone app store has an app called forscan lite. it is 8 dollars. with that and the obd mx adapter, it is quite easy to put it into service mode

 

[thornclaw]

also,
i suggest using bosch esi6 brake fluid. it is a low viscosity fluid that outperforms motorcraft/pentosin dot4 lv.
esi6 dry/wet boiling point 520/360

motorcraft dry/wet bp 509/338

it is $18 on amazon for a quart

 

[WhitePonyRTR]

I’ve flushed the brake fluid in mine once and then bled them a couple more times between track events. I put the car in brake service mode and use a Motive power bleeder. Start at passenger rear, then driver rear, passenger front, driver front. Bleed the inside of the caliper first then the outside on each wheel. Pretty much like any other vehicle except for entering brake service mode. I’ve done it without being in brake service mode as well without any issues, but after removing a caliper without being in brake service mode, I learned my lesson. Better safe than sorry, so I always use brake service mode now.

Krisk and others........ A few quick questions. I want to track my 2024 GT for the first time in October and want to swap out to high-temp brake fluid to be safe.

1) What brand of brake fluid did you go with? Pros/Cons? I see Castrol SRF is rated as the top one, but I don't want to pay $65 a bottle; I see others with a high boiling point at ~$25 a bottle. I am curious to what you ran and if it was Low Viscosity like the Motorcraft DOT4 performance LV, so that it doesn't interfere with the ABS module.
2) I have a Motive bleeder, I planned to use this to pressurize the system and do complete replacement of factory fluid with race fluid..... I am glad I read this post, I did not know "brake service mode" existed. I want to clarify, I can place the car in break service mode and then do the fluid exchange and not have a bunch of codes pop up? Thanks for sending the procedure in previous threads. I want to avoid going to the Stealership for the brake fluid replacement if I can.
3) What camera did you use to shoot that track footage and sync up with the rpm,speed etc? That video was sweet on your other post.

4) Any other tips for my first track day? I saw you were new to it as well. My tires are 90% Nittos, brembo PP up front with 95% pads, brake fluid change out planned, Snell2020 helment purchased......

 

[krisk]

Krisk and others........ A few quick questions. I want to track my 2024 GT for the first time in October and want to swap out to high-temp brake fluid to be safe.

1) What brand of brake fluid did you go with? Pros/Cons? I see Castrol SRF is rated as the top one, but I don't want to pay $65 a bottle; I see others with a high boiling point at ~$25 a bottle. I am curious to what you ran and if it was Low Viscosity like the Motorcraft DOT4 performance LV, so that it doesn't interfere with the ABS module.
2) I have a Motive bleeder, I planned to use this to pressurize the system and do complete replacement of factory fluid with race fluid..... I am glad I read this post, I did not know "brake service mode" existed. I want to clarify, I can place the car in break service mode and then do the fluid exchange and not have a bunch of codes pop up? Thanks for sending the procedure in previous threads. I want to avoid going to the Stealership for the brake fluid replacement if I can.
3) What camera did you use to shoot that track footage and sync up with the rpm,speed etc? That video was sweet on your other post.

4) Any other tips for my first track day? I saw you were new to it as well. My tires are 90% Nittos, brembo PP up front with 95% pads, brake fluid change out planned, Snell2020 helment purchased......

I run Castrol SRF, and yes, it is expensive. I go through about 3/4 of a liter doing a bleed after each track day. I think most people run something a little less expensive such as Motul 660. As far as a ULV brake fluid, it’s really not necessary in a track environment. Where the low viscosity matters is when it is very cold outside and the car is actuating ABS, stability control, etc. Unless you are doing track days in the snow, Castrol SRF or Motul 660 will be significantly less viscous at track temps than a ULV fluid in freezing temps as you would encounter with daily driving. Now, if you’re still going to daily drive it and you drive is freezing temps, you may want to consider sticking with a ULV fluid.

FYI, I’ve stopped putting the car in brake service mode only for bleeding. It’s not necessary as far as I can tell. I’ve bled it with and without service mode, and have encountered no difference. Warning, if you’re removing brake components or changing pads, I would certainly put it in brake service mode. Not doing so is where you can run into problems.

I’m not sure which videos you’ve seen. Initially I was using the Dragy Lap app on my phone with the external Dragy gps. Earlier this year I switched to the Garmin Catalyst because it just works. There’s too much to worry with at a track event, so having a simple device that just works is nice. Plus it provides feedback during and after track sessions.

First track day, the stock PP pads will be fine. You likely won’t have any issues with brake fade. As you progress you will want to switch to a track pad, but you’re fine for now. Just be sure to check your pads regularly. Track use eats them up quickly. I’m getting around 5-6 track days out of a set of front pads. Rears last a little longer. Not sure which Nittos you are running, but be prepared to burn through street tires very quickly on the track. I put a new set of Continental ExtremeContact Sport 02, which are advertised as a “trackable” street tire, on my car and the front tires were gone in either 4 or 5 track days (can’t remember exactly). I’m now running the Continental ExtremeContact Force, which is a DOT legal 200TW track tire. I have 6 track days on them and they have plenty of tread. I’ve heard they are likely to heat cycle out and begin losing grip before they will actually wear out the tread. I’m doing at least 12 more track days this year, but I’ll be happy if these tires make it another 6-8 days. I still carry a set of the Sport 02s for rain use. So far that hasn’t been necessary because all my track days have been dry, but this weekend at Roebling is shaping up to be a wet one, so they’ll likely see some use.

With your tires check the pressures after every session while the tires are hot and inspect them to see how far down you are seeing wear. Adjust the hot pressures up or down to get a good wear pattern. It you run the pressures too low the tires will roll and you’ll get wear down into the sidewall. Try to find info from people who have run your tire on the track to see what pressures they are running.

Enjoy your track day! Warning: It is addictive, and becomes very expensive if you want to do it regularly.

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