Thread: ABS Issue

You have to "bench bleed" the master cylinder/abs pump unit first. Put it in a benchvise. Fill the reservoir with brake fluid. I used a phillipshead screw driver with the tip ground flat to push in the piston. The same spot the brake pedal pushrod goes. Keep pumping away until all the nasty fluid squirts out of all four brakeline ports and the clean fluid starts coming out. Then install the unit, bolt up all the lines, then proceed to bleed all the brakes, starting with the right rear, then the left rear, front right, then front left. Remember to keep checking and filling the master reservoir. This is the proper way to do it. All the air must be out of the master before you can bleed the rest of the system. I recently went ahead and replaced mine as well with a unit from Ed Morad (great people!). I followed the exact same procedure and now all four calipers are working perfectly Any time air is introduced into the system it MUST be bled. Whenever you change the master cylinder the entire system needs to be bled. If you change just the rear calipers then just the rear needs to be bled and so on.

Originally Posted by thirdgenfcarnut

You have to "bench bleed" the master cylinder/abs pump unit first. Put it in a benchvise. Fill the reservoir with brake fluid. I used a phillipshead screw driver with the tip ground flat to push in the piston. The same spot the brake pedal pushrod goes. Keep pumping away until all the nasty fluid squirts out of all four brakeline ports and the clean fluid starts coming out. Then install the unit, bolt up all the lines, then proceed to bleed all the brakes, starting with the right rear, then the left rear, front right, then front left. Remember to keep checking and filling the master reservoir. This is the proper way to do it. All the air must be out of the master before you can bleed the rest of the system. I recently went ahead and replaced mine as well with a unit from Ed Morad (great people!). I followed the exact same procedure and now all four calipers are working perfectly Any time air is introduced into the system it MUST be bled. Whenever you change the master cylinder the entire system needs to be bled. If you change just the rear calipers then just the rear needs to be bled and so on.

Wow, this is great info, I may take it back out and do that with it. the breaks are feeling a tad bit mushy. Thank you very much, this is very helpful!