SinisterC6

while doing a brake job i had my LF line go bad, i let it sit over night and the reservoir went empty. i bled the brakes and used 3 bottles of fluid, the pedal was firm after the bleeding with the car off


today i started the car and the pedal is feeling soft, any advice would be appreciated

breecher_7

Sounds like there is a leak or there is still air in the system. Do you have a pressure bleeder?

SinisterC6

I did It with a vacuum bleeder followed by the old fashion way, I'm going to try bleeding again

Robls6

If the reservoir ran dry you could have pulled air into the system after the seal was broken (when the fluid ran out). I would fill up the reservoir again and bleed it again.

RicK T

Sounds like air may have entered the ABS module. If that happened, AFAIK the only way to bleed the module is with a TechII tool. Please let us know how it goes.

torquetube

With the engine off and no vacuum in the booster, the pedal will feel firm even with a lot of air in the lines.

Anyway, it's very common to have to bleed it again after replacing that much fluid. You'll have an even easier time if you wait until the next morning to let tiny air bubbles rise into the reservoir.

KneeDragr

Ive always like Speed Bleeders for my motorcycles. Id give them a try, cheap and effective.

SinisterC6

I'm not sure how much I should bleed the system, I did the LR caliper until I got new fluid coming through, and did the other calipers until I was see.g new fluid.

should I pass entire reservoir of fluid through each caliper?

Could I bleed with the motor on so that the master cylinder and booster are being used?

How could air enter the ABS? Is them any way to get the air out without using a techII?

torquetube

That's plenty.No.No. The booster just makes the pedal easier to push, which is hardly necessary with a bleed valve open.It's probably fine. There's a thimble of fluid captive in the ABS unit between electronically-actuated valves which are normally closed. This gets mentioned all the time because people want to replace that fluid, too, when doing brake jobs. It'll get mixed in with the rest of the system soon enough.

If your pedal is functional but merely spongy, you're doing okay. Just wait a little bit and bleed it again.

SinisterC6

Will do ill keep you all posted

breecher_7

Im not a fan of the vaccum bleeders, ive had them in the past. The motive products pressure bleeder works awesome though. If you were in the milwaukee area id let you use mine.

SinisterC6

How does conventional bleeding compare to the power bleeder?

breecher_7

the pressure tank screws onto the master resevoir and you build pressure in the system, i usually put about 15psi into it. Then you just crack open the bleed valve and it forces the fluid through the system. In theroy it does the same thing as conventional bleeding but moves fluild much faster and makes it a one man job. Ive read somewhere that it also opens the abs valves above 13psi so it flushes through all the fluid. Unsure if that is actually true though.

pmj341

they are great!!
I got one and I love it
I started on RR then LF, LR then RF per Tech's instructions, drove it a couple of days and did it again and got a great pedal

Bill Dearborn

When you let air get into the upper part of the system it is possible that air can get into the brake pressure modulator valve. Once in there it is difficult to get out without bleeding the brake while operating the valves inside the BPMV. This has happened to a lot of people over the years since ABS systems started being installed in cars. If air is in the unit you need to have a Tech 2 hooked up to the car so it can operate the valves in the BPMV. That means a trip to the dealer or someplace else that has a Tech 2 or equivalent tool.

This is the warning that is in the Service Manual brake bleeding procedure:

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

Bill

SinisterC6

Which model bleeder are you using?

breecher_7

Dont have the model # off hand, its the one designed for late model GM vehicles though... Was $65 shipped to my door.

BEZ06

What did you do? Did you remove the calipers from the car - i.e. disconnect them from the hoses that connect them to the brake lines???

If so, and you got them mixed up, that could be your problem.

The soft pedal you describe after multiple bleedings sounds like the problem many have had after removing and reinstalling the calipers. I've read here on the Forum a number of times that people have had issues getting a firm pedal after getting calipers powdercoated or rebuilt, and it's because they put them on the wrong side of the car.

If the calipers are put on the wrong side of the car and the bleed valves are on the bottom of the caliper you'll never get the pedal firm.

The bleed valves must be on the top of the calipers.

Bob

SinisterC6

just finished bleeding with a friend with the conventional method, since the fluid is new i just recycled what was coming out of the calipers, we bleed out about 1/3 of the reservoir at each caliper and it made a huge difference, the pedal still has about 1 inch of hang. ill be purchasing a power bleeder to make the job faster and to this one more time after driving the car a bit

heres what i upgraded to:

xyz big brake kit

14'' 2 piece slotted rotors all around

6 piston fixed calipers up front with steel pistons

4 piston fixed calipers rear with steel pistons

1 piece ferro carbon pads all around

stainless steel lines

custom cooling ducts up front

BEZ06

Excellent!!! Sounds like you'll have a great system!!!

I use a Motive Power Bleeder with a GM cap adapter like others have mentioned.




It's designed to put fluid into the bottle, but I think many/most of us just use it as a pressure source. You could probably build your own out of a pump-up bug-spray or fertilizer-spray tank, a pressure gauge, a length of tubing, and cap that will fit the brake m/c.

Bob