Brake Light after Bleeding Brakes

02Sub · February 24, 2014

Hello:

I have a 2002 Suburban 2500 4WD with the 8.1L engine.

Today I replaced both rear calipers (dual-piston), and also put in new pads and rotors. This is the first time I have opened the brake hydraulic system. I followed the instructions in the GM service manual for bleeding manually, which was to not run the truck, pump the pedal 3 times, have a helper press the pedal while you loosen the bleeder, etc. More or less the usual way to bleed brakes manually.

During bleeding, it seemed that there was not as much fluid coming out of the bleeder as I expected. I repeated the pedal-push with bleeder loosening process about 6 or 7 times per caliper. After I started the Suburban, the pedal was spongy and the brake light was flashing on and off (along with the two "international symbols" above the word "brake"). I didn't lose much brake fluid out of the hose when I moved it from the old caliper to the new. I doubt air got all the way back into the ABS system, but I suppose it could have.

Should I just try bleeding the brakes again? Is there a trick to bleeding with the ABS system? Does the ABS need to be activated/bled/reset ?

I have a Motive Products pressure bleeder that I have never used, should I try it?

Thanks in advance for the help.

Steve

pm26 · February 24, 2014

I have not had any problems changing brake fluid on my '06 Silverado. I recommend you try a one man bleeding method I use - get a piece of clear vinyl tubing that fits tightly onto your caliper bleeder. Then insert the other end into a bottle half full of brake fluid and make sure it stays submerged during the bleeding process. Open a bleeder about 3/4 of a turn and then aggressively pump the brake pedal about 15 times. You do not have to close the bleeder after each pump using this method. After about 15 pumps, close the bleeder valve and add brake fluid to the master cylinder.

If you have air in the system (and I think you do) this method is far more likely to get rid of the trapped air.

I have been using this bleeding technique for years with outstanding results. You need to make sure of several things during the bleeding process - that the vinyl tubing fits tightly onto the bleeder valve and does not slip off, that the end of tubing stays submerged in brake fluid, and that you do not open the bleeder too far to start sucking in air.

brucelimerick · February 24, 2014

You for sure have air in your system. The brake light indicates low fluid in the reservoir and that one side is out of fluid. You have let air into the rear system at the master cylinder and now have to push it all the way to the back calipers. There is no trick with the ABS nor did you get air back to it. Duals take a fair bit of fluid to fill them. You have to pay attention to the reservoir at the master and keep it full as you bleed the brakes. It is more important than the rear.

I like the 2 person method, a second person to watch the bubbles. Once they stop you are done if you haven't let air in the front end. I have my pedal person pump the brakes until the pedal firms up and have them hold pressure on the pedal and push it to the floor when I crack the bleed screw. I tighten the bleed screw before they let the pedal come back up. Tube in a bottle in fluid. At the start 10 to 15 pumps is not out of reason, once the air is mostly gone 3 or so. Do the back passenger side first (longest). The brakes should be firm without pumping when the air is gone. PM26's method will work fine if you don't let air in either end. You can use more fluid than required to do get the air out because you can't tell if the system is firming up as you go or see just clear fluid coming out the tube. But if you have no helper it will work just fine. An extra can of fluid is cheaper than 24 beer, lol.

02Sub · February 24, 2014

Thanks for the ideas.

The master cylinder never went dry and the lowest the fluid level dropped to during bleeding was halfway between the min and max fluid level marks.

Should I try pressure bleeding with the Motive pressure bleeder? I bought it about 8 years ago and its still in the box unused. I notice a bunch of people use the Motive pressure bleeder, but some have said not to use it because it doesn't have a diaphragm between the air and the fluid. They claim this could introduce air into the system. Any thoughts?

Steve