Bleeding Brakes?
Le Mans Master
Joined: Aug 2010
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according to the book I have , the only issue is that you raise the front of the car so that air wont be trapped in the rear calipers, with one of the vacum or preasure bleeders you probably wont need to do that. other wise seems pretty straight foward, I used to preasure bleed from rear foward, but any method that gets the air out is good. The reason I started doing the preasure bleed foward was due to the early versions of ABS. they've probably improved them by now.
Last edited by oldalaskaman; Feb 4, 2011 at 11:08 PM.
Le Mans Master
Joined: Feb 2005
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From: Clearwater Florida
........... The '87 FSM recommends starting at right front to right rear then left rear and finally left front ... the old school way is to start at the wheel furthest from the master cyl ... this is still the case except that the ABS is behind the drivers seat so the fluid passes through there before going out to the wheels ...
Le Mans Master
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From: Life is just one big track event. Everything before and after is prep and warm-up and cool-down laps
Cruise-In III Veteran
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St. Jude Donor '12
IIRC it depends on the year. The FSM has the proper order.
On my 92 I've been using passenger rear, driver rear, passenger front, driver front.
Don't even know if that is correct, but it works. One day I'll look in the FSM
On my 92 I've been using passenger rear, driver rear, passenger front, driver front.
Don't even know if that is correct, but it works. One day I'll look in the FSM
Team Owner
Joined: Dec 1999
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From: Lacey WA RVN 68-69
NCM Sinkhole Donor
Some people say that with ABS cars, there is no real need to use a specific sequence when bleeding. I have watched techs in our shop simply start bleeding at the point where they are standing. Some guys still use a gravity bleed method and some will use a pressure bleeder.
"Old school" procedures (pre-ABS) were to simply start with the wheel furthest from the master cylinder and move closer in turn. With ABS systems, the lines from the master go to the ABS pump and then the individual lines go from there to each wheel.
With 86 and later C4's, the ABS pump is behind the driver's seat so the "distance" for bleeding is determined from that point. Bleeding the ABS system itself is another issue. Later C4 ABS systems require a GM Tech-2 with the brake module or a similar scan tool to allow the ABS pump to operate. Same with the C5 system. And bleeding the C4 pump is a PITA because the bleed port is on the side of the pump down in the compartment. Gets real messy
But the ABS system does a self-test every time the car moves forward so a small amount of fluid passes thru the pump from the M/C.
"Old school" procedures (pre-ABS) were to simply start with the wheel furthest from the master cylinder and move closer in turn. With ABS systems, the lines from the master go to the ABS pump and then the individual lines go from there to each wheel.
With 86 and later C4's, the ABS pump is behind the driver's seat so the "distance" for bleeding is determined from that point. Bleeding the ABS system itself is another issue. Later C4 ABS systems require a GM Tech-2 with the brake module or a similar scan tool to allow the ABS pump to operate. Same with the C5 system. And bleeding the C4 pump is a PITA because the bleed port is on the side of the pump down in the compartment. Gets real messy
But the ABS system does a self-test every time the car moves forward so a small amount of fluid passes thru the pump from the M/C.
Le Mans Master
Joined: Aug 2010
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I used to pressure bleed from the wheels 'to' the abs, and then pressure from the abs 'to' or actually thru the master cylinder, pushing the fluid out the top . it was a little messy and probaly not nessessary, but I didnt have the scan tools and it eliminated 'air left in the system' comebacks.
