The Continuing Brake Saga
Thread Starter
Melting Slicks
Joined: Nov 2002
Posts: 2,471
Likes: 2
From: 1993 Quasar Blue 'vert Scottsdale AZ
The Continuing Brake Saga
I've made a couple of posts about my brake problems in the last couple of weeks, and thanks to all of you that offered suggestions. At the advice of Merle at EM, the first thing I did was have a power flush at Midas(flame). They did a good job except when I asked about flushing the ABS, they said that no fluid goes through it, it is just bunch of dang sensors. Well, the brakes worked great for about a week, no more dragging. Trevor asked if the ABS worked, and truthfully, in 4 years, I have never felt it activate. He told me to go out, run at about 40 to 50 mph and slam on the brakes. I did this, and it was the first time I actually had the system kick in. I did it about a dozen times. Drove down to EM today and the brakes started dragging again. Trevor drove it, the ABS worked, but the brakes felt funny. Checked the new fluid and it was filthy already! Merle came up with the theory that if the ABS hadn't been activated in years, it was probably full of crud, and activating it sent that crap into the lines. So I turkey basted it out and plan on activating the crap out of it this weekend to clear it out and do another flush. Does this make sense to you?
Drifting
Joined: Jan 2001
Posts: 1,408
Likes: 13
From: Dayton, Ohio
Please keep us posted on how it works out. I'm getting ready to
put on braided hoses, and maybe a new master cylinder.
By the way, how do you activate the ABS while bleeding ?
It would be helpful if anyone knows as this would save a bunch
of time instead of flushing, hard braking , re-flushing...
put on braided hoses, and maybe a new master cylinder.
By the way, how do you activate the ABS while bleeding ?
It would be helpful if anyone knows as this would save a bunch
of time instead of flushing, hard braking , re-flushing...
Team Owner
Joined: Dec 1999
Posts: 34,873
Likes: 487
From: Lacey WA RVN 68-69
NCM Sinkhole Donor
The ABS pump does a self-test everytime the car is started, put into any gear and you move thru 2-4MPH. You should hear a short (2-3 seconds) buzzing noise directly behind the driver's seat. This test circulates a small amount of fluid between the ABS pump and the M/C.
The only realy way to "flush" the ABS pump is with a GM Tech-1 or II Scan Tool with the brake module installed. That will run the pump continuously. To flush the pump, the fluid is let out at a port on the side of the pump. Messy job to do as there is no bleeder like the calipers have and the storage compartment is sealed.
Most all GM techs will tell you that the only time the ABS pump is flushed is when a new pump is installed.
The comment from the guy at Midas is bull-poopie. The ABS does move fluid thru lines back to the M/C but it only applies and releases pressure at the lines that go to the calipers when the ABS system activates during braking. Bleeding fluid at the calipers pulls fluid from the master cylinder reservoir and that process bypasses the ABS pump.
If you sense a "dragging" brake, you may have a caliper piston that is sticking. Are the calipers original? If they are, it may be time to have new calipers installed (atsome place other than Midas
) .
The only realy way to "flush" the ABS pump is with a GM Tech-1 or II Scan Tool with the brake module installed. That will run the pump continuously. To flush the pump, the fluid is let out at a port on the side of the pump. Messy job to do as there is no bleeder like the calipers have and the storage compartment is sealed.
Most all GM techs will tell you that the only time the ABS pump is flushed is when a new pump is installed.
The comment from the guy at Midas is bull-poopie. The ABS does move fluid thru lines back to the M/C but it only applies and releases pressure at the lines that go to the calipers when the ABS system activates during braking. Bleeding fluid at the calipers pulls fluid from the master cylinder reservoir and that process bypasses the ABS pump.
If you sense a "dragging" brake, you may have a caliper piston that is sticking. Are the calipers original? If they are, it may be time to have new calipers installed (atsome place other than Midas
) .
Team Owner
Joined: Jun 2005
Posts: 46,295
Likes: 2,596
From: Northern, VA
St. Jude Donor '15
"In honor of jpee"
In the distant past, I spoke with several brake techs re ABS and the consensus of opinions was: you need to activate your ABS every once in awhile just for the reasons that c4 has pointed out above. Another very good reason is so you know what it feels like when it activates in an emergency situation. Not unlike throwing your car around a bit in a safe parking lot (read: empty) when you first get new tires to see how they work compared to the old pair. Or just for the heck of it.
The other thing I learned from them is, again like c4 says, fluid def flows through the ABS system/sensors, and if the brake fluid gets contaminated or dirty, it will affect the sensors. Sometimes it ruins them and requires that they be replaced. There are some new car mfrs that now require the brake system to be flushed on a specific period of time, regardless of miles, or the warranty is voided on that componentry.
Great question and hope your situation turns out ok.
The other thing I learned from them is, again like c4 says, fluid def flows through the ABS system/sensors, and if the brake fluid gets contaminated or dirty, it will affect the sensors. Sometimes it ruins them and requires that they be replaced. There are some new car mfrs that now require the brake system to be flushed on a specific period of time, regardless of miles, or the warranty is voided on that componentry.
Great question and hope your situation turns out ok.
Safety Car
Joined: Jan 2006
Posts: 3,566
Likes: 4
From: Mt Laurel NJ
St. Jude Donor '06-'07
Originally Posted by corvette_bob
Please keep us posted on how it works out. I'm getting ready to
put on braided hoses, and maybe a new master cylinder.
By the way, how do you activate the ABS while bleeding ?
It would be helpful if anyone knows as this would save a bunch
of time instead of flushing, hard braking , re-flushing...
put on braided hoses, and maybe a new master cylinder.
By the way, how do you activate the ABS while bleeding ?
It would be helpful if anyone knows as this would save a bunch
of time instead of flushing, hard braking , re-flushing...
I am suprised the brake fuild does not always go thur the ABS. I would love to find out how to bleed the ABS.Thanks
Thread Starter
Melting Slicks
Joined: Nov 2002
Posts: 2,471
Likes: 2
From: 1993 Quasar Blue 'vert Scottsdale AZ
Well, I've been driving around all weekend, stomping on the brakes to activate the ABS, then siphoning the fluid out of the MC and repeating. I'm having a brake upgrade next week, so I'm just trying to get some of the crap out of the ABS unit, then will do a complete flush. Like mentioned earlier, you need to activate the unit occasionally so crud doesn't build up in it.
