Brake Fluid Queston
Safety Car
Joined: Apr 2004
Posts: 4,813
Likes: 2
From: We cant stop here... this is bat country
Drifting
Joined: May 2005
Posts: 1,590
Likes: 1
From: Littleton Colorado
Can't say 100% on the cap, is there another GM cap or just that one? I'd asusem its that cap though.
If you do get speed bleeders you could still do a one man bleed without the motive.
From everything I've read on the subject, synthetic silicone based brake fluid is absolutely not recommended for cars with ABS systems. The reasons stated are that the pulsing of the ABS can introduce air pockets into the system and cause all sorts of problems getting the air out again. And the pedal will be hard and require more pressure. LMA dot 4 is a good choice. Dot 3 is OEM and for most street driving is also a good choice. The silicone based synthetics are great for restored antiques, and classics, preventing rust in the lines and wheel and master cylinders, but not for modern ABS systems. So unless there is new knowledge out there, that is what I've read on the subject.
Drifting
Joined: May 2005
Posts: 1,590
Likes: 1
From: Littleton Colorado
Since your doing the rotors as well I though I would add some more hints. I'd also advise getting a LONG breaker bar to break the caliper bracket bolts loose, mine is 18 inch and I'd like it longer. Or use a smallish impact wrench to remove them, may need an impact swivle to get the impact wrench on the bolt. The rears are the hardest, with the fronts you can move the steering knuckle around to get good leverage on the bolts. Get some penitrating oil, like wd40, and soak the bolts overnight. It may help.
You may have problems getting the rear rotors off. After making sure the parking brake is off, don't be afraid to use a small sledge on them.
The bolts and the rear rotors are the hardest parts about the process.
Lastly, don't forget to pick up some blue and red loctite. And some good brake grease. Grease the pads where they contact the caliper and bracket, and grease the caliper slide pins.
You may have problems getting the rear rotors off. After making sure the parking brake is off, don't be afraid to use a small sledge on them.
The bolts and the rear rotors are the hardest parts about the process.
Lastly, don't forget to pick up some blue and red loctite. And some good brake grease. Grease the pads where they contact the caliper and bracket, and grease the caliper slide pins.
Instructor
Joined: Feb 2007
Posts: 115
Likes: 9
From: Tampa FL
Thanks
Kudos. It is AMAZING how much some of these contributors know - and all of us appreciate your willingness to pitch in. Also, I really appreciate that forum members are quick to correct mis-information in a kind way.
I've been using Valvoline Synpower for 3+ years (with ABS) and have never had a problem. Thanks for clearing up the difference between Dot 5 (Silicone) and Synthetic.
I've been using Valvoline Synpower for 3+ years (with ABS) and have never had a problem. Thanks for clearing up the difference between Dot 5 (Silicone) and Synthetic.
Le Mans Master
Joined: Sep 2003
Posts: 8,847
Likes: 795
From: Longview Texas
I replaced the master cylinder on my Z06 and I was able to fill the master cylinder and bleed all the lines until I got clean fluid out with just one quart of fluid. I just stayed with Prestone DOT3 that is available at Walmart.
If you leave the cap on the master cylinder, you will no lose much brake fluid at the calipers when you change them. We take them loose all the time to paint them, and lose only a few drops.
Once the new calipers are in place, then you can remove as much old fluid for the master cylinder reservoir as possible, fill with clean fluid, and bleed the brakes until you get clean fluid out. The ABS and Active Handling circuits are normally closed, so you should not have any problem getting air into those circuits.
If you leave the cap on the master cylinder, you will no lose much brake fluid at the calipers when you change them. We take them loose all the time to paint them, and lose only a few drops.
Once the new calipers are in place, then you can remove as much old fluid for the master cylinder reservoir as possible, fill with clean fluid, and bleed the brakes until you get clean fluid out. The ABS and Active Handling circuits are normally closed, so you should not have any problem getting air into those circuits.
Last edited by TEXHAWK0; Oct 15, 2008 at 11:16 PM.
Instructor
Joined: Jan 2009
Posts: 149
Likes: 1
From: Houston Texas
If you are going to open a line to replace a caliper, here is a trick that works well: Place a piece of Saran Wrap over the mouth of the MC reservoir and replace the cap. The cap is vented to allow the fluid to move into the lines and the Saran Wrap will effectively prevent this while you are replacing the calipers and/or flexible lines. Don't forget to remove the Saran Wrap when you are done 
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Burning Brakes
Joined: Nov 2008
Posts: 764
Likes: 0
From: Arden NC
Gary
I thought Castrol LMA was a synthtic.
Get a turkey baster or 50 cc surynge for mixing gas and oil for a 2 cycle motor. Putt 4" of Tygon tubing on the tip. 1/4" ID
Car should be on four jack stands and all four wheels off
Suck out the old brake fluid from the MC.
Fill the MC with new brake fluid.
Start with right rear.
10 mm wrench.
attach bleed bottle, Old clear soda bottle Coke or Pepsi with hole though top and 12" of tygon tubbing though.
attach end of tygon tube to bleed screw.
Pump up Power bleeder 15-20 psi 25 is fine too. No less then 12 psi.
OPen bleed screw and watch the brake fluid drain out. 1/2 turn until brake fluid is flowing.
Make sure tygon tubing is tight on the bleed screw
When clear brake fluid is coming though the tubing. tighten bleed screw, check pressure in Power bleeder tank.
May have to put more new fluid into MC tank. Dont let MC run dry.
( NOTE: DO NOT PUT BRAKE FLUID INTO POWER BLEEDER TANK. That gets very messy and wastes brake fluid )
Do rear two calipers. PUT CAP BACK ON MC
Then pump brake peddle 3,4, 5 times too assure brake peddle is firm.
Put more brake fluid in MC, put on power bleeder, pump up to 15-20 psi and do front two calipers.
Remove Powerbleeder cap, put up to 3/4 full of MC
NOTE: FOR ANY TRACK USE DO NOT FILL MC. PUT NO MORE THEN 3/4 FULL OF MC. Hot brake fluid expands. If the MC is full, where will that HOT brake fluid go?
Bake fluid is costic and WILL eat paint. Keep lots of rags around.
Put wheels on and go for short drive to check brakes.
If peddle is not firm, put the car back on four jack stands and re bleed the brakes.
Good Luck
I thought Castrol LMA was a synthtic.
Get a turkey baster or 50 cc surynge for mixing gas and oil for a 2 cycle motor. Putt 4" of Tygon tubing on the tip. 1/4" ID
Car should be on four jack stands and all four wheels off
Suck out the old brake fluid from the MC.
Fill the MC with new brake fluid.
Start with right rear.
10 mm wrench.
attach bleed bottle, Old clear soda bottle Coke or Pepsi with hole though top and 12" of tygon tubbing though.
attach end of tygon tube to bleed screw.
Pump up Power bleeder 15-20 psi 25 is fine too. No less then 12 psi.
OPen bleed screw and watch the brake fluid drain out. 1/2 turn until brake fluid is flowing.
Make sure tygon tubing is tight on the bleed screw
When clear brake fluid is coming though the tubing. tighten bleed screw, check pressure in Power bleeder tank.
May have to put more new fluid into MC tank. Dont let MC run dry.
( NOTE: DO NOT PUT BRAKE FLUID INTO POWER BLEEDER TANK. That gets very messy and wastes brake fluid )
Do rear two calipers. PUT CAP BACK ON MC
Then pump brake peddle 3,4, 5 times too assure brake peddle is firm.
Put more brake fluid in MC, put on power bleeder, pump up to 15-20 psi and do front two calipers.
Remove Powerbleeder cap, put up to 3/4 full of MC
NOTE: FOR ANY TRACK USE DO NOT FILL MC. PUT NO MORE THEN 3/4 FULL OF MC. Hot brake fluid expands. If the MC is full, where will that HOT brake fluid go?
Bake fluid is costic and WILL eat paint. Keep lots of rags around.
Put wheels on and go for short drive to check brakes.
If peddle is not firm, put the car back on four jack stands and re bleed the brakes.
Good Luck
This is great information!
