I have been told that you have to "flush" the brake fluid on our cars periodically.

So when I do my brakes, I thought I'd go ahead and do this.

Does someone have a GM shop manual and explain to me the proper way to bleed the ABS unit.

 

Lee,
You don't have to bleed the ABS unit since the fluid runs through it anyway to get to the brakes. (GM mechanic told me that tip a few years ago)

Make sure you haven't tripped the ABS light in the past few days before starting the bleeding process or else you'll have to get the ABS unit re-cylced.

Start with the farthest away from the master cylinder and work towards the closest to the MC. Rear right, rear left, front right, then front left.

One person will be inside the car pumping the brakes while another will be doing the actual bleeding at the calipers. A third person would be very helpful to make sure the master cylinder doesn't run out of fluid. But thats not needed if you check it periodically.

Pour the fresh fluid into the MC until its to the very top. Put the cap back on. Have the person inside the car start pumping the brake. Then you loosen the bleeder screw in the caliper until fluid starts to come out. NOTE..you should connect a small clear hose about 18" long to that bleeder screw and run it to a catch pan. Don't get that brake fluid in your eye!!! The person in the car will get a good leg workout cause they'll be pumping alot!! Watch the fluid. It'll be dirty at first then turn into the clean new fluid. When that happens, tighten the bleeder screw in the middle of a brake pump to make sure air doesn't get sucked back into the caliper.

If you don't have that third person handy to watch the MC then after about 5-7 brake pumps (rear) you'll need to check the fluid level. It'll only take about 2-4 pumps to drain the MC dry when doing the front. So watch it carefully. If it goes dry, you need to start all over again.

 

or, the person in the car pumps about 3 times, holds it on the 4rd, open the bleeder screw, let foot/pedal hit the floor, tighten bleeder back up, take foot off pedal

 

Either that or you could go buy some self bleeder screws and make it a one man job.

 

Where do you get self bleeder screws? I need some

 

I you are going to replace all the fluid, or it has drained because you removed and rebuilt or powder coated the calipers, you should bleed the master cylinder(s) prior to bleeding the calipers or you may be chasing more air thru the system.

Loosen the output fitting on the front MC, and pump until clear fluid and no bubbles come out. Retighten and repeat with the rear cylinder. This is right out of the shop manual.

We just did all this to a C5 Vette, and flushed the system with about 24 oz. of brake fluid. By then only clear fluid was coming out. Bleeding the MCs and then the calipers in the correct order (farthest to nearest the MC) gave excellent results.

My $.02

 

This is some good info.

My question is: Do I pump with the car running?

 

Nope, car doesnt need to be running. Don't think I have ever seen it done that way but I guess it could.

 

http://www.thunderracing.com/index.c...ategoryid=1006

Click on brake bleeders. Usuall your local auto parts store will have them. Just make sure you get the correct thread and pitch. HTH

Joe

 

Thanks for the responses everybody.


I looked in my Haynes manual this morning and it said that if the car has traction control (TCS), and I do, that you can't do this without a special tool of some sort. The book said take it to a dealer.

Anybody ever do this on a car with traction control?

 

I have traction control and, since I didn't know any better, flushed the brakes as per first post. Worked fine. Done it twice now.

 

Ok cool... Thanks for the info!

 

Just my opinion, but I don't care for those so called speed bleeders. Why? Well, I've tried them and I found they they don't work as well. With the oem bleeder screws I can "crack" them open just enough to use my Mity-Vac manual power bleed ($35) and vacuum the old fuid out and with one twist close them up air tight. I can't seem to do it that easily with speed bleeder jobs. To get those speed bleeder screws to work one needs to make several rotations of the wrench. Unless you have vacuum applied you may get air back into the caliper when you have to remove the wrench and make another tightening rotation of the bleeder screw. No thanks. I like using a simple and easy to use power bleeder like the Mity-Vac. They are other more expensive power bleeders on the market and I can use the same tool for other shop purposes (i.e. bench bleed a master cylinder, test an EGR diaphram's vacuum, etc)

 

Where can I get info about the Mity-Vac?

 

Teflon Tape!!


I do my brakes Solo.... I wrapped two or three turns of teflon tape on the bleeder screws threads.. I plug a long clear hose in the bleeder screw... I opened it.. I route the long clear hose up where I can see it from inside the drivers side... and hang it up with the other end hanging into a container.... I pump the brakes slowly till no more bubles come up ....and I dont have to worry about sucking any air back in... cause its sealed around the thread and in will only suck fluid from the hose back in... but only a little....

Its so easy, I am very surprised people havent figured out the air is getting sucked in through the bleeder screws threads and calipers... I have teflon taped wraped on all the OEM bleeder screws up and including the ABS Unit. I have seen the bleeder screws at the auto parts store but how the hell do in get the right thread and right pitch without removing a bleeder screw from my car???

Try it... one or two times around the screws thread is all it takes for a snug fit that wont let the air in...


Marvin