sperkins

I used the ole turkey baster to suck out the old fluid from the brake master before bleeding with my Motive power bleeder. I've done this before with no problems, but I guess I went a little too far this time because when I got back in the car (before bleeding at the wheels) the pedal is mushy. I've read in cases like this that the dealer may have to purge the ABS pump with the Tech2 tool. I'm not going to have time tonight to bleed the system, but I'm wondering now if I should even bother. Is it possible to cycle the ABS pump on the street enough to fix this problem or should I just cut my losses and head for GM?

2003 ZO6

fatbillybob

I have a C5Z never had this problem but I have bleed zillions of ABS cars. What you need to do is active the ABS pump which is what the tec2 does. Use the two man method skip the motive. Yes they work but not as well as 2 man dispite what everyone says.

Bleed in this order RR, LR, RF, LF 1/2pt in each rear to get a air out from the master, 1/4 pt from each front should be about right.

I'm not sure how to active the ABS in C5's. Some cars will active the ABS pump if the key is in position 2, i.e. car in the run position but does not need to run. Some cars only run the ABS pump if the engine is on...more dangerous to work on.

Once the ABS is active say with engine on you can bleed like normal 2 man method. If engine is on be careful and your driver needs to be careful so you guys don't kill each other. I've seen pretty dumb things in my day. If you know you got air but it does not seem to come doing the trick of driver pressing brake and you suddenly opening bleeder quickly moves the air with a jolt through the lines. If the abs pump starts running that good. stop bleeding until the abs pump pressures up and stops then bleed again until you have no more air in the lines.

If you lack experience and really need to know you got the fluid traveling the full car length you can use ATE super blue fluid. You suck out the gold in the master and add in blue. When you bleed and see blue you know you got a clean system. Next time you suck out the blue and add in the gold and bleed until you see gold. This works great for rookies.

If you still have problems sometimes you got so much air you have to reprime the master. You can read on the web about that but basically you run fluid from the master output right back into the master filler a bunch of strokes until you get good air free fluid to come from the output side of the master. Then you reconnect brake lines and bleed each line to each caliper. You would need to screw up pretty bad to need this.

Hope that helps.

flink

(note: assumes that GTO ABS = vette ABS)

yeah, I got air in my ABS when installing stainless lines (tried to save time
when bleeding ).

I must have put half a gallon through the system trying to get it out, no dice.

I went out and found some roadway with sprinkler runoff and skidded around
for a while, triggering the ABS, no dice.

Ended up getting it fixed via two trips to the dealer for a tech2 bleed, $400.

However one GTO owner recently said that he did fix it by going out and
triggering the ABS a lot of times on wet roads (he got lucky - it was raining).
I don't know why this could work - the fluid in the brake system stays put, so
even if you did move the bubbles a bit, what could cause them to be pushed
out of the ABS unit?

From your description, it is possible that the air is in the master cylinder and
not in the ABS. There should be an on-car master cylinder bleeding process.
On the GTO that simply involves loosening the front brake line on the M/C
and letting it dribble fluid for a few minutes.

mousecatcher

sounds like you would like my ABS brake bleeder tool!

looks like my thread got deleted, strange. i was considering building a tool to bleed the ABS. I would sell it for $250.

96CollectorSport

If you don't want to go the tech2 method the only way is to bleed the car, then drive in and activate the ABS, re-bleed hoping that you got the air out. You could do this once and get lucky or you could end up doing it 100 times and still not get the air. You may just have to bite the bullet and go to the dealer.
Oh and the tech2 bleed the series goes LF RF RR LR.

BEZ06

I'm no expert on the system, but I think one of the problems people have when flushing the system is that they can't flush the ABS circuit without a Tech 2, and they still have old fluid such as DOT 3 in the ABS circuit when trying to flush the system when switching over to DOT 4.

So....I think that your ABS circuit is still isolated from the rest of your brake lines unless you activated it somehow while bleeding, and although you might have gotten some air into the regular lines, you probably didn't get any into the ABS circuit.

I bet you can bleed the system to get the air out of the lines and you'll be okay.

Butt....like I say, I'm no expert and may have a misunderstanding of what happened when you got air in the lines.

Bob

Z06Fix

I was going to suggest getting as much pedal as you can by bleeding then taking it out for a drive. Find some way to trickle the ABS several times. Repeat process till you get our full pedal feel back. I had to do this in my 03 cobra after installing the Brembo's.

I thought the correct bleed sequence on a C5 and C6 was: RR LF LR RF. Is it different when using the Tech 2?

mousecatcher

The tech2 bleed series is diagonal, because each of the two ABS circuits controls a diagonal pair of wheels.

It is RR LF LR RF. When bleeding manually it doesn't matter what order you bleed in. At home I do the fronts than the rears, just because it's convenient to have 1 end of the car off the ground at a time. At the track where I only can jack one side of the car at a time, I do one side at a time.

exracer28

I have my own Tech II and when I see you at the track we can do a bleed. When is your next event?

John

Aardwolf

I'm not familiar with the '03 ZO6 ABS unit since I don't have one but it may have a bleeder on the ABS unit. I'd think there would be a way to apply 12 volt to the ABS to make it run without having to drive around.

sperkins

Man you guys are spot on here.

That's exactly what I was thinking and hoping Bob.

That's what I plan on doing after I bleed it the best I can.

I'm glad someone finally cleared this up. There have been numerous threads arguing this point. Thanks!!

Wow John - your generosity never ends. I'll be at Road Atlanta in a few weeks with NASA so if you make it please look for me. Hope all is well with you.
Thanks again,
Scott

Bill Dearborn

Just to be clear its not just the ABS that is controlling a diagonal set of wheels the 01 and up cars use a dual diagonal base brake system. There is no connection between the rear brakes and there is no connection between the front brakes. This way if one of the circuits fails you always have one front brake and one rear brake.

Bill

varkwso

You taking notes from Falcon? Do not take a pistol drill anywhere near your radiator

trackboss

If there were a stand alone tool to activate the abs for bleeding I'd buy one. All it needs to do is hold the circuit open.

davidfarmer

I've always wondered it bleeding, followed by going out and activating the ABS, followed by more bleeding, rinse repeat etc, would eventually get the air out?

Anyway, unless you pumped WHILE the resevoir was empty, any air should have floated back up when fluid was added. I do this all the time

RC45

I noticed that as well. I guess you have to be a fully paid up vendor just to discuss a possble product launch.

fatbillybob

on my c5z I changed to ss lines and just bleed the car with either the car running or key in position2. It worked fine. I bleed regularly and if you are trying to bleed a buble you need to bleed the farthest lines first. If you are just bleeding trackside for a spongy pedal then it does not matter which wheel you do. In all the abs cars I have had I have never had to use a dealer tool to trigger the abs. I have replaced calipers, lines, masters too.

Jason

Or Khoi with a jack.

Z06cool

You can't count that. My plan failed. His radiator was untouched...

Umrswimr

Tried multiple gallons of brake fluid. No dice.

Took it to the dealer who bled them and blamed the brake pads. $100.

Took it to a shop and explained exactly what I needed- $250 and it's fixed. Wrote a letter to the dealer and got my $100 back.

Take it in. You won't get far on your own with this one.