Need to change my brake fluid for an event, anyone have links to a how-to?

[Cobra4B]

Thanks!

[gmblack3]

If this is your first bleed you may want to think about having a dealer do it with the Tech II, which activates the ABS when they do the bleed. You may not get any of the fluid out of the ABS system doing it yourself. When you engage the ABS at the track you will mix your old fluid that is still in the ABS system in with the new. Some say that you can do the bleed yourself then go out and engage the ABS then rebleed.

There also has been an article in some recent vette magazine that claims you need to bleed with the key in the off position then the on position. They claim that will get the fluid out of the ABS system. I don't understand how this would work as your ABS in not engaged when you turn the key on.

Get some speedbleeders from ***edited***

First try and get all the fluid you can out of the reservoir with a turkey baster or syringe. You will see that you can't get all of the fluid out of the fwd part of the reservoir.

You will need at least 2 quarts of fluid, having the 3rd quart will not hurt.

Note the bleed order is RR, LF, LR and RF on 01 and newer vettes.

Steps 1-3 are for bleeding the master cylinder, so skip them if this does not apply to you.


1. Place a clean shop cloth beneath the brake master cylinder to prevent brake fluid spills.

2. With the ignition OFF and the brakes cool, apply the brakes 3-5 times, or until the brake pedal effort increases significantly, in order to deplete the brake booster power reserve.

3. If you have performed a brake master cylinder bench bleeding on this vehicle, or if you disconnected the brake pipes from the master cylinder, you must perform the following steps:

A. Ensure that the brake master cylinder reservoir is full to the maximum-fill level. If necessary, add Delco Supreme 11®, GM P/N 12377967 (Canadian P/N 992667), or equivalent DOT-3 brake fluid from a clean, sealed brake fluid container. If removal of the reservoir cap and diaphragm is necessary, clean the outside of the reservoir on and around the cap prior to removal.

B.With the rear brake pipe installed securely to the master cylinder, loosen and separate the front brake pipe from the front port of the brake master cylinder.

C. Allow a small amount of brake fluid to gravity bleed from the open port of the master cylinder.

D. Reconnect the brake pipe to the master cylinder port and tighten securely.

E. Have an assistant slowly depress the brake pedal fully and maintain steady pressure on the pedal.

F.Loosen the same brake pipe to purge air from the open port of the master cylinder.

G.Tighten the brake pipe, then have the assistant slowly release the brake pedal.

H. Wait 15 seconds, then repeat steps 3.3-3.7 until all air is purged from the same port of the master cylinder.

I. With the front brake pipe installed securely to the master cylinder, after all air has been purged from the front port of the master cylinder, loosen and separate the rear brake pipe from the master cylinder, then repeat steps 3.3-3.8.

J. After completing the final master cylinder port bleeding procedure, ensure that both of the brake pipe-to-master cylinder fittings are properly tightened.

4. Fill the brake master cylinder reservoir with Delco Supreme 11®, GM P/N 12377967 (Canadian P/N 992667), or equivalent DOT-3 brake fluid from a clean, sealed brake fluid container. Ensure that the brake master cylinder reservoir remains at least half-full during this bleeding procedure. Add fluid as needed to maintain the proper level. Clean the outside of the reservoir on and around the reservoir cap prior to removing the cap and diaphragm.

5. Install a proper box-end wrench onto the RIGHT REAR wheel hydraulic circuit bleeder valve.

6. Install a transparent hose over the end of the bleeder valve.

7.Submerge the open end of the transparent hose into a transparent container partially filled with Delco Supreme 11®, GM P/N 12377967 (Canadian P/N 992667), or equivalent DOT-3 brake fluid from a clean, sealed brake fluid container.

8.Have an assistant slowly depress the brake pedal fully and maintain steady pressure on the pedal.

9.Loosen the bleeder valve to purge air from the wheel hydraulic circuit.

10.Tighten the bleeder valve, then have the assistant slowly release the brake pedal.

11.Wait 15 seconds, then repeat steps 8-10 until all air is purged from the same wheel hydraulic circuit.

12. With the right rear wheel hydraulic circuit bleeder valve tightened securely, after all air has been purged from the right rear hydraulic circuit, install a proper box-end wrench onto the LEFT FRONT wheel hydraulic circuit bleeder valve.

13. Install a transparent hose over the end of the bleeder valve, then repeat steps 7-11.

14. With the left front wheel hydraulic circuit bleeder valve tightened securely, after all air has been purged from the left front hydraulic circuit, install a proper box-end wrench onto the LEFT REAR wheel hydraulic circuit bleeder valve.

15. Install a transparent hose over the end of the bleeder valve, then repeat steps 7-11.

16. With the left rear wheel hydraulic circuit bleeder valve tightened securely, after all air has been purged from the left rear hydraulic circuit, install a proper box-end wrench onto the RIGHT FRONT wheel hydraulic circuit bleeder valve.

17. Install a transparent hose over the end of the bleeder valve, then repeat steps 7-11.

18. After completing the final wheel hydraulic circuit bleeding procedure, ensure that each of the 4 wheel hydraulic circuit bleeder valves are properly tightened.

19. Fill the brake master cylinder reservoir to the maximum-fill level with Delco Supreme 11®, GM P/N 12377967 (Canadian P/N 992667), or equivalent DOT-3 brake fluid from a clean, sealed brake fluid container.

20. Slowly depress and release the brake pedal. Observe the feel of the brake pedal.

Important
If it is determined that air was induced into the system upstream of the ABS modulator prior to servicing, the ABS Automated Bleed Procedure must be performed.


21. If the brake pedal feels spongy, repeat the bleeding procedure again. If the brake pedal still feels spongy after repeating the bleeding procedure, perform the following steps:

A. Inspect the brake system for external leaks. Refer to Brake System External Leak Inspection .

B. Pressure bleed the hydraulic brake system in order to purge any air that may still be trapped in the system.

22. Turn the ignition key ON, with the engine OFF. Check to see if the brake system warning lamp remains illuminated.

Important
DO NOT allow the vehicle to be driven until it is diagnosed and repaired.

23. If the brake system warning lamp remains illuminated, refer to Symptoms - Hydraulic Brakes .

[Cobra4B]

Thanks for the info... I'm going to have fun this next weekend doing all this stuff! Looks easy enough to do, and I'll have my dad helping me so I don't need the speed bleeders just yet (great product though)

I heard that the fluid in the ABS unit never gets close to the heat etc of the brakes so it's ok to just leave it and let it mix w/ the new stuff.

[No Doubt]

I heard that the fluid in the ABS unit never gets close to the heat etc of the brakes so it's ok to just leave it and let it mix w/ the new stuff.

When the new fluid which has a higher boiling point, assuming you use a DOT4, comes in contact with the older DOT3 (lower boiling point) the old DOT3 fluid instantly boils.

Now, over time and after a few ABS engagements and bleeds the old fluid will be purged, but in the meantime you're mixing the two whenever you engage ABS.

[Cobra4B]

That would only happen if the fluid was up to that higher temp. so if I had a few abs engagements, before getting the fluid super hot, the lower temp fluid would disperse into the other fluid.

[Subdriver]

That would only happen if the fluid was up to that higher temp. so if I had a few abs engagements, before getting the fluid super hot, the lower temp fluid would disperse into the other fluid.

Correct, meaning you have diluted the new good fluid with the old not so good DOT 3 fluid. How much of a negative impact will this have? Who knows.

DJ and others will say to use the Tech II mentioned above. I will say this is the best way, but not the only way, especially for a novice on the track.

I did what you are doing two years ago. I did not do the tech II flush. My method was a feed and bleed approach.
- Replace fluid in reservoir with new Motul fluid.
- Bleed all four corners until only new fluid comes out.
- Drive car active ABS several times.
- Rebleed all four corners until only new fluid comes out.
- Drive in first track day activating ABS several times (to say the least).
- Rebleed all four corners at the end of the day until only new fluid comes out.

At that point, I think it is fair to say you have almost completely flushed the old stuff out.

If you have the time and money, tech II is best. If not, the above is fair alternative.

[DJWorm]

The only problem with bleeding and activating the ABS yourself rather than with a Tech II is you never know which ABS circuits were activated and the old fluid may in fact still be present in the system even after a couple of street ABS activations.

What invariably happens is on a new track or with a new driver or both, the brakes are used sparingly at first until familiarization has occured. Now the brakes and fluid are hot. Sooner or later as confidence is increased a braking point is missed and a corner is over cooked!....and the ABS is activated.....and it works!! Now as the driver is hurtling down the back stretch he is thinking,

"Hey these brakes are fantastic and I can really hold speed and dive in to the corner much deeper. The ABS will save my ass!"

All the while the crappy fluid he has just dumped into the system from the first Racing type full ABS activation...which involved all the wheels and circuits, has already vaporized. Now with the new found confidence he takes the corner close to the usual course lapping speed and finds the pedal mush all the way to the floor....while Pucker factor and the ARMCO gets closer.... and closer..... and closer.

Why risk a $50,000 car and possibly your life for something that's so simple. Hey, I like you guys. Let's just buy the best fluid, pads, lines and use the Tech II the first time correctly. It's simple and insignificant cost wise. Don't cut corners on the simple stuff....that's what will kill you.

[Cobra4B]

hmm.. I just didn't want to pay the dealer $70 on something I could do myself. How much fluid is held in the ABS components that wouldn't come out. I'm just doing one track even, not begining a full season of racing. I figure if I flush then do some ABS stops then bleed again I shoud be just fine for my needs. I dunno you know a lot more about tracking these cars than I do...