Birdie2000
Club Member
Just got done doing the brakes on my 2000 Cavalier. It's a front disc/rear drum setup. Decided since it was so cheap just to go ahead and replace the rear wheel cylinders while we were rebuilding the drums. This of course meant bleeding the brakes, and I figured this would be a good idea since it would give me an opportunity to get some clean fluid in there.
I followed the GM service instructions for manually bleeding the brakes without a scan tool. Here is the exact procedure I followed:
1.) Start car twice to verify no ABS light and to open cylinders in ABS module.
2.) Crack open each of the 4 lines on the ABS unit one at a time, going from left to right. Cracked it open, waited for fluid to flow naturally, pressed brake pedal 75% of travel, closed fitting while fluid was steadily coming out if there was no noticeable bubbles. This is the part I was nervous about, the only other time I've bled an ABS module it had it's own bleeders and the process was exactly the same as bleeding a caliper. I'm unsure how you'd see bubbles when just cracking a line and letting it drip, but that's what it said to do.
3.) Bled the brakes in the following order: right rear, left front, left rear, right front. This is the order the factory service instructions specified so that's what we did.
Now the two rear drums where we replaced the wheel cylinders bled just fine, steady stream of clean fluid with no bubbles whatsoever.
The front calipers are another story. On neither one of them could we completely remove all the bubbles. No matter what, there would be a stream of tiny bubbles coming out that almost would look like carbonation. We bled each one for about 15-20 minutes a piece, and we can bleed pretty quickly. There was no sign of this getting any better. The funny thing was that when it was the old dirty fluid coming out, there were no bubbles whatsoever, but when the clean fluid started coming through they started.
So we say fuck it, let's leave it and see what happens. The pedal was firm and it wasn't sinking. So we start up the car, and the pedal is relatively soft and just barely travels all the way to the floor. At this point is was getting late so we called it a night.
Any ideas or suggestions? The only thing I can think of is that the ABS unit wasn't properly bled, but it would be nice to not have to take it to a dealer just to get the brakes bled with a scan tool and pressure bleeder. I have a friend with a Tech2 that I'm going to call later and see if he feels like helping, but I'd like to have some idea of what I'm up against and why the bubbles would be constant like that with no sign of improvement. We didn't loosen any fittings at the caliper and the abs fittings are tight.
I followed the GM service instructions for manually bleeding the brakes without a scan tool. Here is the exact procedure I followed:
1.) Start car twice to verify no ABS light and to open cylinders in ABS module.
2.) Crack open each of the 4 lines on the ABS unit one at a time, going from left to right. Cracked it open, waited for fluid to flow naturally, pressed brake pedal 75% of travel, closed fitting while fluid was steadily coming out if there was no noticeable bubbles. This is the part I was nervous about, the only other time I've bled an ABS module it had it's own bleeders and the process was exactly the same as bleeding a caliper. I'm unsure how you'd see bubbles when just cracking a line and letting it drip, but that's what it said to do.
3.) Bled the brakes in the following order: right rear, left front, left rear, right front. This is the order the factory service instructions specified so that's what we did.
Now the two rear drums where we replaced the wheel cylinders bled just fine, steady stream of clean fluid with no bubbles whatsoever.
The front calipers are another story. On neither one of them could we completely remove all the bubbles. No matter what, there would be a stream of tiny bubbles coming out that almost would look like carbonation. We bled each one for about 15-20 minutes a piece, and we can bleed pretty quickly. There was no sign of this getting any better. The funny thing was that when it was the old dirty fluid coming out, there were no bubbles whatsoever, but when the clean fluid started coming through they started.
So we say fuck it, let's leave it and see what happens. The pedal was firm and it wasn't sinking. So we start up the car, and the pedal is relatively soft and just barely travels all the way to the floor. At this point is was getting late so we called it a night.
Any ideas or suggestions? The only thing I can think of is that the ABS unit wasn't properly bled, but it would be nice to not have to take it to a dealer just to get the brakes bled with a scan tool and pressure bleeder. I have a friend with a Tech2 that I'm going to call later and see if he feels like helping, but I'd like to have some idea of what I'm up against and why the bubbles would be constant like that with no sign of improvement. We didn't loosen any fittings at the caliper and the abs fittings are tight.