Sounds like I need a new MC. A big THANKYOU, to all of you! I will repost with the results in a few days.

 

Do not overlook your rear brake shoe adjustment

 

I had the rear shoes adjusted right after the brake job. I could tell by applying the parking brake there was to much slack. One other question I have....if there is still air in the brake lines, shouldn`t the pedal still offer some resistance. I don`t feel much pressure against my foot? Thanks for the advise, you and everyone else have been a tremendous help.

 

With just a little air left in the brake lines of my 96, I could put my foot on the pedal and it would slowly go to the floor. It doesn't take much air to really screw up the system.

I use a vacuum pump and clear hose that I can see the air bubbles in as I bleed the system, I don't stop until NO air bubbles are present.

 

Larry, what kind of a vacuum pump do you use?

 

It is similar to this one, they do make a kit that is a little less than that one as well. http://www.nationaltoolwarehouse.com...qx/product.htm

 

Air in the system doesn't cause the the pedal to creep to the floor if you pump the brakes several times to build up pressure.
Easy way to tell if you have a mechanical problem or just need to bleed some more.

 

[QUOTE=Lary Ellis (Top);2909117]It is similar to this one, they do make a kit that is a little less than that one as well. [URL="http://www.nationaltoolwarehouse.com/xq/asp/N.Silverline-Elite-Automotive-Test-Kit/PID.MTY-MV8500

The test kit shown on the "NTW" website, provides both vacuum or pressure. Can you recharge a new MC ( reverse bleed ) through the brake cylinder bleeder valve? If this is possible, it would be quicker and require a lot less fluid. My brake pedal does creep to the floor, so I picked up a new MC today. Sorry I spelled your name wrong.....LARY

 

reverse filling is a bad idea, as you force used dirty fluid back thru the brake system, most all the dirty fluid is in the calipers/wheel cyls, as this is where the majority of heat occurs, best case is to flush from the MC out to the calipers, this gets rid of the old fluid.
brake fluid should be flushed periodically, this ensures maximum like and effeciency of the brake components.

alway bench bleed the MC before installing it.

best bleeding set up is a one man bleeding kit, a piece of rubber hose and a clean bottle, works perfectly every time

 

Installed new BMC.....NO change!! Pedal still creeps to the floor,with motor running (it is not spongy). Pedal hard as a rock with motor off. What else could be causing this problem??

 

Just forget it and drive, I went through the same issue 4 years ago, did a brake job, got the sinking pedal, I changed several master cylinders and always got the same thing. 4 years now , stops great, no leaks , pedal will still sink slowly with the engine running, every 12v I have been in did the same thing.

 

Normal driving would be fine, BUT.....if I have to make a panic stop, and can`t......which is what I had to do comming into Colorado Springs. Lady luck was smilling on me that time. I have not driven the truck since I changed the BMC, and maybe it is a little better, even though the pedal acts the same. Did you look at any other options, like changing the booster??

 

diesel 96, do you have 2wheel ABS or 4?

At least on the 2WABS the diverter valve can cause what you describe.

 

I would entertain thoughts of changing the booster, if someone can explain to me how a brake booster could cause a brake pedal to slowly sink to the floor. The ONLY thing that can cause that other than a leak, is some sort of issue with the master cylinder. I have tried several different ones all with the same issue. Air in the system will cause a spongy pedal. I have no trouble with panic stops , or stopping my 40' gooseneck.

 

I would bleed them again,I liketo gravity bleed,just open a bleeder and the cover on the master and let it flow,takes a little longer but I feel good about refilling the master a couple times, always good to change the fluid.