Any Special Procedure for Bleeding ABS?
Thread Starter
Le Mans Master
Joined: Feb 2000
Posts: 9,715
Likes: 27
From: Kempner Texas
Any Special Procedure for Bleeding ABS?
I've had an Anti-Lock dash light on my 86 for quite a while now, so I just finsihed installed another Control Module and Modulator Valve hoping to cure the problem.
Yes, I did all the trouble shooting procedures first. All the relays were checked as well as the wiring asnd ground. One of the tests let me know that my Modulator Valve (pump) was dead since 12V didn't activate it. I could no longer hear it come on when I first started the car and began to drive away.
I haven't reconnected the battery yet, because I wanted to ask if there's any special bleeding procedure that needs to be followed.
The GM Shop Manual for the 86 Vette doens't make any mention of a special procedure. All it does is refer me to the bleeding section which give the bleeding instructions that are no different than if I'd have changed pads.
The bleeding sequence is different though. For the 86 it's LEFT REAR, RIGHT REAR, LEFT FRONT and RIGHT FRONT, not starting at the brake fartherest from the master cylinder as I have been use to.
If anyone knows of anything "special" about bleeding the brakes/ABS I'd like to know about it before I begin later this evening. I plan to use the pump the pedal, hold the pedal, open the bleeder, etc., procedure.
Thanks,
Jake
Yes, I did all the trouble shooting procedures first. All the relays were checked as well as the wiring asnd ground. One of the tests let me know that my Modulator Valve (pump) was dead since 12V didn't activate it. I could no longer hear it come on when I first started the car and began to drive away.
I haven't reconnected the battery yet, because I wanted to ask if there's any special bleeding procedure that needs to be followed.
The GM Shop Manual for the 86 Vette doens't make any mention of a special procedure. All it does is refer me to the bleeding section which give the bleeding instructions that are no different than if I'd have changed pads.
The bleeding sequence is different though. For the 86 it's LEFT REAR, RIGHT REAR, LEFT FRONT and RIGHT FRONT, not starting at the brake fartherest from the master cylinder as I have been use to.
If anyone knows of anything "special" about bleeding the brakes/ABS I'd like to know about it before I begin later this evening. I plan to use the pump the pedal, hold the pedal, open the bleeder, etc., procedure.
Thanks,
Jake
Thread Starter
Le Mans Master
Joined: Feb 2000
Posts: 9,715
Likes: 27
From: Kempner Texas
Originally Posted by Hooked on Vettes
According to my 89 manual you fill the master cylinder and bleed the brakes just like you do with a non ABS system.
Thanks for that.
Guess I'll head out to the garage and have at it.
Jake
Drifting
Joined: May 2003
Posts: 1,979
Likes: 48
From: Lakeport CA
Std bleed process is fine, just don't put the pedal all the way to the floor & bottom out your master cyl.
2 things I learned at a one day ABS class a few years ago.
1) 90% of the pumps are the same (Bosch). You can buy the pump for any chevy (or other cheaper car) w/ ABS, swap the brackets from your stock pump & take your old one back in for the core charge. Most parts houses have a few in stock so you can check first.
2) Find a nice gravel or grass parking lot, get it to 7 MPH, hit the brakes hard enough to engage the pump. Guess what, the pump will pump out air for you!!
Repeat as necessary for the fun, the experience of feeling the pedal shudder & bleed any lingering trapped air. Who could ask for more??
2 things I learned at a one day ABS class a few years ago.
1) 90% of the pumps are the same (Bosch). You can buy the pump for any chevy (or other cheaper car) w/ ABS, swap the brackets from your stock pump & take your old one back in for the core charge. Most parts houses have a few in stock so you can check first.
2) Find a nice gravel or grass parking lot, get it to 7 MPH, hit the brakes hard enough to engage the pump. Guess what, the pump will pump out air for you!!
Repeat as necessary for the fun, the experience of feeling the pedal shudder & bleed any lingering trapped air. Who could ask for more??
Last edited by Trog; Mar 24, 2005 at 02:06 AM.
Le Mans Master
Joined: Apr 2000
Posts: 6,294
Likes: 0
From: Amateur driver on open course.
I bled mine from furthest away first (RR) and so on. LR,RF then LF. I posted a response to another post awhile back, and then someone posted from a repair manual, a different procedure. Maybe they'll see this and post the order again.
Thread Starter
Le Mans Master
Joined: Feb 2000
Posts: 9,715
Likes: 27
From: Kempner Texas
Originally Posted by 95AquaC4
I bled mine from furthest away first (RR) and so on. LR,RF then LF. I posted a response to another post awhile back, and then someone posted from a repair manual, a different procedure. Maybe they'll see this and post the order again.
heads.I'd become accustomed to starting at the caliper fartherest from the MC, but my GM Shop Manual says to start with the driver's side rear, then psngr rear, then driver's front and then psngr front.
But, like you, I saw another post where a different year - mine's an 86 -uses a different sequence.
Anyway, I just finfished bleeding them doing it the Manual way and works like a charm.
Thanks to the great deal with VetteNoob my ABS is back up and running again; no more Anti-Lock light.
Jake
Last edited by JAKE; Mar 24, 2005 at 05:21 PM.
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Thread Starter
Le Mans Master
Joined: Feb 2000
Posts: 9,715
Likes: 27
From: Kempner Texas
[SNIP=Trog]
2) Find a nice gravel or grass parking lot, get it to 7 MPH, hit the brakes hard enough to engage the pump. Guess what, the pump will pump out air for you!!
Repeat as necessary for the fun, the experience of feeling the pedal shudder & bleed any lingering trapped air. Who could ask for more??[/SNIP]
That's really interesting. Where does the air go? I mean how does the ABS vent it?
Jake
2) Find a nice gravel or grass parking lot, get it to 7 MPH, hit the brakes hard enough to engage the pump. Guess what, the pump will pump out air for you!!
Repeat as necessary for the fun, the experience of feeling the pedal shudder & bleed any lingering trapped air. Who could ask for more??[/SNIP]
That's really interesting. Where does the air go? I mean how does the ABS vent it?
Jake
Safety Car
Joined: Jul 2001
Posts: 3,886
Likes: 0
From: Northern California
Originally Posted by JAKE
Apparently the sequence differs by year. GM loves to play games with out heads.
I'd become accustomed to starting at the caliper fartherest from the MC, but my GM Shop Manual says to start with the driver's side rear, then psngr rear, then driver's front and then psngr front.
But, like you, I saw another post where a different year - mine's an 86 -use a different sequence.
I'd become accustomed to starting at the caliper fartherest from the MC, but my GM Shop Manual says to start with the driver's side rear, then psngr rear, then driver's front and then psngr front.
But, like you, I saw another post where a different year - mine's an 86 -use a different sequence.
I think the sequence mattered more on 1966 and earlier cars where all 4 wheels got fluid from the same source. Front and rear have been on separate hydraulic systems since 67, and then the ABS came along and split the two front wheels into 2 channels. I now worry about the sequence only on the two rear wheels, since they are still fed from the same source (assuming the Vette ABS is 3-channel).
