Terrible Juan

Well, I believe that air somehow got introduced into the master cylinder, either by running it too low when I was bleeding it, or air getting sucked back into it when I was doing the front-driverside caliper.

I'm wondering how I would go about bleeding the entire system properly on this car. In the past, I've done it by pressing the brake down and cracking open each of the hard lines on the master cylinder until the air gets out, and then doing a complete bleed at each caliper. This car has ABS and I'm wondering at which point during the bleed will I need to bleed the ABS unit in the rear storage compartment?

Any help?

For a 93, by the way.

QuikZilver

Not sure completely, as I always had a shop do the brake flush for me on my old 93. But, I do remember that once you introduce air into the system (running the mc dry), you will have pulled air into the ABS module. Apparently, the ABS module is not something fun to bleed. I had a shop flush the brakes and did not raise the rear of the car high enough and the ABS module took in some air. I had to take it to the dealership to be re-flushed to correct what the other shop had done. Hopefully, some that have done this themselves will chime in. Driving with no brakes, sucks!

Terrible Juan

Yea, I know that the ABS unit could cause some problems. I'm just wondering in which order I should bleed? Hopefully it won't give me too much of a hassle. If worst comes to worst, I will take it to the dealer and have it done properly.

So, should I be cracking open the master cylinder hard lines first or the ABS unit?

Terrible Juan

? ? ?

Kevin Woods

1. Call in a buddy to help.

2. Disconnect all brake lines at the caliper.

3. Pump brake peddle and add brake fluid, keeping the reservoir as full as possible.

4. With each brake compression, check the fluid coming out.......look for fresh fluid (NOTE: Keep peddle compressed while buddy checks the lines).

5. When fresh fluid comes out of a line, reconnect that line.

6. Continue until all lines are reconnected.

7. Top off reservoir to spec and close the lid .

NOTE: If you do not keep the brake peddle compressed while re-attaching the brake line, air will get into the line!!!!!!


KW

Harryscarlot

the order in which they should be bled is right rear, left rear, right front, left front. I've been doing this for over 23 years and have always bled one caliper at a time. I'm not understanding the disconnect ALL brake lines and pumping the brake pedal procedure (unless you have a person at each caliper), maybe I'm not just reading it right. Unless all the brake lines are immersed in brake fluid, you're going to suck air back in if you pump the brake pedal.
You pump the brake pedal,hold the pressure on it, and have someone loosen the bleeder screw. tighten up the screw, pump the pedal til firm, bleed it again while holding pressure. tighten up. continue doing this until you don't see any bubbles coming out of the bleeder screw. **make sure you only loosen the bleeder screw a 1/4 to 1/2 a turn **. If you loosen too much, you can let air in past the threads. move on to the next caliper in the order at the top all the while keeping an eye on the level of fluid in your reservoir. that is the way they taught us in school and that order is right out of an ASE tech book. always the farthest caliper from the booster to the closest (for you right hand drive car owners). go to your auto parts store and get a one man bleeder kit for a coupla bucks.it'll give you the instructions right on it. it'll make your job a lot easier if you don't have any help around. I use a power vacuum bleeder, but the manual version will work too. hope this helps somewhat. -Harry

rockken_vette

The above procedure does not address the ABS unit in the rear compartment. The Chevy manual did say something about it that had to be done special (but I don't have it here). Do keep lots of towels around and a plastic hose and/or little jar to catch fluid inside the car.

You should only have to do the 5 bleeder screws once the master cylinder is properly primed.

c4cruiser

The procedure in the FSM for bleeding the ABS punp is to use a Tech-1 with the brake module to run the pump in order to pass fluid thru the system.

There is no bleed screw on the pump, only a plug. Bleeding the ABS can get real messy as there is no real way to attach a hose and collect the fluid as it's pumped thru. Dealers (or shops) may have a way to attach tubing to collect the fluid.

In any event, if the M/C reservoir went dry, you may also have to bench bleed the master cylinder to get any air out of it.

Removing any air from the M/C and bleeding of the calipers should get the service brakes working. You can remove the fuse for the ABS and the brakes should still work.

In any event, the ABS self-test that is performed each time the engine is startred and the car moves thru 3-4 MPH, should disable the ABS if there is air in the pump unit. You could then get a shop that has a Tech-1 to bleed the ABS side.

Kinkajou

I am not sure this applies to a 93 but the procedure is for a 94.
First drive a little the car until you reach about 6 to 10mph, park.
THis will unblock some valves at the ABS, you could also do it with a Tech 1.

2. Fill the master cylinder reservoir with fresh brake fluid.
3. Behind the drivers side, in the compartment , the ABS unit can be reached. You have to bleed the prime pipe first, using only gravity. Conect a clear tubing so you can see how the fluid moves , then close.
4. Start by bleeding each caliper starting: right rear, then left rear, right front and finally left front.

I installed powerbleeders and they are just great, but you can have a friend help, use a powerbleeder or vaacuum bleeder.

And you are done, not difficult but time consuming if you do not have Speedbleeders.
Just remember to keep the reservoir with fluid, otherwise you will have to start again.

Good Luck