Brake Flush Problems ... Need Help

[96sc]

My first attempt at flushing the brakes did not go well. I am not sure, but I may have air in the system from letting the fluid in front part of reservoir get too low. I have two problems: 1) I have no brake pedal (I can mash it to the brake pedal stop with engine off and ignition on). 2) Slight buzzing noise coming from engine compartment (?ABS Modulator?) when the brake pedal is released.

Here is a description of what I did:

1) Removed old fluid from reservoir. Filled with new fluid. With helper, flushed the right rear using bleed valve, clear tube, and catch bottle. I added fluid to the reservoir 3 times. When I added on the 2nd time, I noticed the front part of the reservoir was empty. Finished flushing right rear and pumped pedal several times to build up pressure ... the pedal never did build pressure ... I could mash it to the pedal stop.

2) Guessing that I had allowed air into the system, I read the factory service manual bleed procedure. Following the bleed procedure, I bled the rear and forward ABS modulator bleed valves. After bleeding forward valve, I began to hear the "buzz" when pedal was released. Then I once again bled the right rear (no air bubbles were released). Then I bled the left rear (air bubbles were initially present) until air bubbles disappeared. I maintained the correct reservoir fluid level this time! But still not firm brake pedal ... and now I have the annoying (but very quiet) "buzz".

Any ideas on what is the problem and how to fix? I will continue tomorrow (with bleeding the front brakes) and finally another bleed of the ABS modulator. Maybe that will fix it.

[zlexiss]

I'd try bleeding again, this time with either a vacuum (mity-vac) or pressure (motive) bleeding system. They might work much better on getting all the bubbles out of the system.

[grayman]

just throwing this out....those syptoms could occur if one of the bleed valves was left open.

[96sc]

Called lots of different parts stores trying to find a pressure bleeder ... nobody has one. I was advised by a couple of parts store employees to try a "gravity bleed". I'll give this a try and see what happens.

[zlexiss]

I got my vacuum bleeder kit at Sears (they sell a cheap one and a craftsman one). Try there.

[Red]

...Filled with new fluid. With helper, flushed the right rear using bleed valve, clear tube, and catch bottle...

this catch bottle had fluid in it to not allow air right? Not saying you dont know more than me, just had friends catch in cup and didnt have fluid to stop air from being sucked in.