96 Stratus Brake Problem

Dimished brake performance. New Pad/Rotor, Rear shoes. Lot of pressure required to stop, getting worse over time. Car has ABS. Brake system bled,
no leaks at calipers or rear wheel cyls.
With engine off, I can press the brake pedal and it will feel firm and stop several inches from the floor board.
With engine running (in park, not moving), the pedal goes to the floor.
Is it the master cyl, power brake assist, ABS ??
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

From your description of the problem it sounds like none of the above. Have you checked the calipers for stuck pistons or sticking calipers slides ? Are the wheel cylinder pistons frozen in their bores ? Are the rear brakes adjusted properly ? Is the parking brake adjusted properly ? Are you sure there is no air in the brake system ?
If the master cylinder was bad the pedal should go to the floor whether the engine is running or not. If the brake booster was bad it should cause a hard pedal. The ABS should not have any affect on the brake system while sitting in park.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Thanks for your input on diagnosing the Master Cyl / Booster.
I'm curious as to why the pedal goes to the floor when the engine is running ? Is the booster creating that much more force than my leg pushing on the pedal as hard as I can while engine off?
The rears were worn pretty bad, only had about 24K miles on them, original shoes lasted about 45 K Do you think the rears are more braking than the fronts?
Since the pads / rotors were replace a few months ago; also worn, and suspect for pedal travel. The pedal travel did get a bit better with the new pads/rotors, but still required more brake pressure than normal (normal is what I compare with my '96 sebring...same brake system). The pistons did move back freely into the caliper (note, had the bleed screw open when I pushed them in).
"air in system".....how much fluid should I bleed off? I let the fronts gravity bleed; replace at least 12 oz. Finished off the bleeding with somebody assisting; pumping the brake pedal (only 1/2 way down,never to the floor). Have had success with this process on my chrys and ford cars.
================================================================================================ Mike wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
If you did not open the bleeders when the job was done then there would be no reason for air to get into the system. If the rotors were machined and not to a fine cut you will get that feeling when trying to stop. You dont state the mileage and keep in mind that if you have alot of build up around the inside bore of the master cylinder (because the piston never went that far) and you pushed the brake pedal to the floor (possibly tearing the seal) now when you press the pedal the fluid is going passed the seals and causing the fluid to not compress thus making the pedal go down. The other thing is when a brake job is done on a vehicle it has a tendency to feel different then before they were replaced and the owner will acually think the pedal goes to the floor. If the pedal really went to the floor the Brake lite would have turned on when this happens and I see no mention of that happening. Did the brake lite turn on or is it just a matter of seating the pads to the rotors? Just a thought!!!
Glenn Beasley Chrysler Tech
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
No Brake Light ever came on.
I did open the bleeders to do a gravity feed on the front calipers.
Re: rotor fine cut and pedal pressure, pedal travel, are you saying that an improperly cut rotor, may require excessive pedal pressure, and then I'm pushing harder on the pedal, causing it to travel further? Shouldn't the pedal feel firm when the depressed?
damnnickname wrote:

--
Message posted via CarKB.com
http://www.carkb.com/Uwe/Forums.aspx/dodge/200608/1
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

What I am saying is, if the rotors were not cut fine the pad to rotor contact will not be sufficient untill the pads seat to them.As far as brake pedal feel you should know how it is supposed to feel

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.