NoOne

Mike,

That does make sense and I guess I never thought of that. Your not flowing air(well an incredibly small amount), just pressurizing the MC.

I am waiting for an answer on the ABS unit from the supplier that makes the unit for GM if pressure bleeding will take care of the unit or not.

Dicecal

I was reading the 2006 Service manual last night, and it states to flush the system...just do a pressure or manual bleed procedure with the fluid tank full. It also stated in another section that the ABS would be bypassed duing a normal pressure or manual bleed. The only way to get the old fluid out of the ABS unit is with a tech II.

COBrien

For those doing a pressure bleed, are you finding that it alone is enough to get the brakes solid, or do you then do a manual bleed once you've finished with the pressure bleed? Also, any opinions on pressure bleeder vs. vacuum bleeder (like the MityVac)? I've been trying to decide between the approaches...both seem like they should work, though in theory I think the vacuum bleed could potentially let some air back into the system through the threads of the bleed screw.

Also, AU N EGL, you commented that you only add fluid to the master cylinder, not to the reservoir in the pressure bleeder. Just curious why?

daveydc5

Some feel that the pressure bleeder 'aerates' the fluid while you pump it up to pressure. I put the fluid in the pressure bleeder and go to town. Always got a rock hard pedal.

yellow01

Because it's alot of fluid, can make a mess, you end up wasting some, and brake fluid is one of the more unfriendly things to clean up/spill. (both cost and corrsive nature)

It is much easier/cleaner to just use the motive for pressurization and detach/reattach a few times.

COBrien

I'd wondered about that, but it seems if you don't have fluid in the pressure bleeder, bringing up the pressure would then just have the same effect on the fluid in the MC reservoir...

Thanks for the info, glad to hear the Motive is working out for you. Right now I'm about 90% sure that's what I'm going to go with.

COBrien

OK, thanks. I agree it seems easier just to keep adding fluid to the MC reservoir; that way you ensure you have the right amount in there, waste less fluid, and have less chance of a spill. I'd assume using the pressure bleeder reservoir would basically overfill the MC reservoir, and at the end of the bleed procedure you'd have to open a bleeder valve and drain the MC down to the max fill line.

yellow01

Not exactly.

The pressure bleeder has a pickup tube that goes down one side of the resevoir. As long as the M/c is at a decent level, it stays at that level as the pressure pushes more fluid into the master as you bleed. The air at the top of the M/C resevoir has no where to go (it doesn't go back into the bleeder) so the level in the M/C never changes.

When you are done bleeding (assuming you've put fluid in the pressure bleeder) simply turn or tilt the pressure bleeder so the pickup is no longer in fluid for the last bit of bleeding. The pressure will force the fuild already in the pickup and tube through as you finish bleeding, then you simply disconnect the lid. Voila!

the problem with that method is you will almost always have a little fluid in the bottom of the pressure bleeder that must be disposed of. Additionally, if you don't clean the tube you will get crud built up in there (I know personally) and then you risk contamination.

It is far easier/cleaner IMHO to just use the bleeder for pressure. A compressor/lid like many describe above will work, but I didn't want to have to worry about overpressurizing or getting moisture in (compressors will capture alot of water vapor).

Hope this helps!


Jon

COBrien

OK, understood, thanks!

I think I'll probably not bother putting fluid in the pressure bleeder reservoir unless I'm fully flushing the system. For a simple bleed, it's not a big deal if I need to remove the pressure bleeder once or twice in order to add fluid to the MC.

Thanks again for all the help!!

Falcon

Even if you flush the complete system, it isn't a big deal to fill the reservoir each time it gets low until completely flushed. I do it every couple of weekends and there's never a mess to clean up and I'm finished in no time.

z060ntrack

Originally I was going to post that at least on the C5 every time you turn the key to inignition the ABS controller automatically cycles. I used to do one complete bleed (all 4 corners) with the ignition on and then one with it off.

I now have a C6 and hey there aint no key!!!! I suppose you could bleed with the engine running