FastAl

I'm starting to get annonyed now. Long story short I had to replace my front drivers side caliper. That went well and I bled it real quick using the 2 man method.. Had a soft pedal and the car would barely stop on a quick spin around the block. I've now bled through an entire small bottle of brake fluid and still a soft pedal.

I've tried bleeding with the car off and running. Seems to do more with it off, but then as soon as I go it is soft again. I've done both pumping the pedal several times and then holding it and cracking open the bleeder and opening the bleeder and having the pedal pushed down to the floor and neither seems to work. I can't find any leaks. What does sound odd is I hear air moving in the engine compartment?

Any suggestions what I should do from here? I've got another buddy coming over later this evening and we are going to try again under a halogen but I really need this done tonight so I can make the dyno day I setup and have my new tires put on!

VIP1

There may be air in the ABS unit. The only way to get that fixed is to take it the dealer and have them hook it up to their machine (I think its called a Tech II).

--VIP1

mitchntx

iTrader: (14)

Clarification please.

When you pump the pedal, hold pressure and crack the bleeder screw, the pedal is supposed to go to the floor.

It should be held there until the bleeder screw is closed and then released.

Then begin pumping once again and repeat the process.

A soft pedal is indicative of air in the system.

When you flush a solid system, you start at the furthest point from the MC and work your way to the closest.

When chasing an air bubble, you work just opposite ... bleed from the closest and chase the air to the farthest.

And a small can of brake fuid is not very much. I have flushed litres of fluid chasing an air bubble.

wrencher

iTrader: (2)

Now that you drove it bleed it again.
Once you go 15 mph the ABS will do a dump valve cycle in the hydraulic control unit, as long as no ABS faults/codes are present.
If any air was in the hydro unit it was passed to the wheel & you can now purge it.

mitchntx

iTrader: (14)

I've never had good luck with that methodology.

I'm not sure that isn't urban legend.

I've even done the above 15, have an ABS event, and rebleed the system without shutting the car off.

FastAl

Got it bled, a friend of mine who works on cars came over last night and we just did the standard 2 man bleeding some more. I can only assume either my helper was not pushing the pedal all the way down or was letting it up a bit, or that it just needed to be bled a lot more in order to work.

SDB

iTrader: (7)

get SS brake lines and use Ford HD brake fluid which will firm things up a lot! Obviousl you have some air in their now, but since your spending so much time and effort, get the Earls Hyperfirm SS lines and a couple of cans of FOrd fluid and bleed away. I just did mine and they feel great, very firm pedal.

mitchntx

iTrader: (14)

SDB ... you have a firm pedal from fresh fluid because of the flush you did BECAUSE you changed the lines.

The SS braided lines are for heat resistance.

wrencher

iTrader: (2)

It's not a "urban legend" it's a fact on all GM ABS IV systems.
If there is air in the HCU & you do not have a tech-II this is how you get it out.