Question: front brakes dragging

[morespeed69]

I have a 2000 convertible c-5 and i noticed that my front wheels were dragging. So I bled the brakes There was air in the lines ,but after air was removed the front wheels were close to being locked up. I also notice a groaning noise while depressing the pedal. Not sure what was causing the noise.The car only has 29,000 miles on her. Has anyone else had a similar issue and how did you solve it

 

[dadaroo]

I would think a caliper is not retracting if it were only on one wheel but you say the issue affects both front wheels. I wonder if the issue is in the master cylinder.

Is the groaning sound happen when you are not moving?

 

[dadaroo]

I just remembered in the C5 the left front and right rear share a common line as do the right front and left rear. This is to prevent losing all brakes on the front and rear. This adds a little twist on having both front brakes that are dragging.

I wonder if the EBCM is somehow activating the front brakes.

I would like you to start the car and ensure you are having this issue. BEFORE you turn the engine OFF pull your DIC codes and let's see if anything shows up. Some EBCM and PCM codes do not show once you turn the engine off.

 

[morespeed69]

Its not putting out any codes When I drive the car the active handling is taking time to warn up which is new.I'm thinking its the master cylinder or the power booster

I just remembered in the C5 the left front and right rear share a common line as do the right front and left rear. This is to prevent losing all brakes on the front and rear. This adds a little twist on having both front brakes that are dragging.

I wonder if the EBCM is somehow activating the front brakes.

I would like you to start the car and ensure you are having this issue. BEFORE you turn the engine OFF pull your DIC codes and let's see if anything shows up. Some EBCM and PCM codes do not show once you turn the engine off.

 

[dadaroo]

Try pulling the Engine Fuse Box fuses 5 and 52 to disable the EBCM and see if it has any affect.

 

[morespeed69]

ill try pulling fuses. Will I be able to drive the car if the ebtcm is disabled?

 

[dadaroo]

Yes, no problem to drive, you will have normal braking but no ABS,AH, or TC.

 

[morespeed69]

I did notice that while bleading the brakes I didn't get much fluid from front as I did the rear

 

[dadaroo]

In order to help diagnosis what your issue is I looked into the FSM. It DOES NOT show the design as I described. I had stated that from another Forum post. It didn't sound right but I took it as true.

The FSM shows the front brake hydraulics are separate from the rear brakes.

The EBCM (using the BPMV internal valves) does regulate the pressure between the fronts and the backs like purely mechanical pressure regulators have done in the past. It could be that this might be a source of your issue. For this to be the cause it would require 2 of the internal valves (in parallel) to close, one for each wheel.

I would also like to know if you have the wheels off the ground and you replicate the problem and wait does the pressure bleed off so you can easily rotate the wheel?

 

[morespeed69]

In order to help diagnosis what your issue is I looked into the FSM. It DOES NOT show the design as I described. I had stated that from another Forum post. It didn't sound right but I took it as true.

The FSM shows the front brake hydraulics are separate from the rear brakes.

The EBCM (using the BPMV internal valves) does regulate the pressure between the fronts and the backs like purely mechanical pressure regulators have done in the past. It could be that this might be a source of your issue. For this to be the cause it would require 2 of the internal valves (in parallel) to close, one for each wheel.

I would also like to know if you have the wheels off the ground and you replicate the problem and wait does the pressure bleed off so you can easily rotate the wheel?

Lots to tell since last post. Removing fuse no difference in the braking.. Got to thinking that maybe I hit debris on freeway. I put car in the air and front wheels spinning free and now rear is binding up What do you think??

 

[dadaroo]

Did you remove both fuses?

Are both back brakes binding?

Try braking several times and see if the issue returns to the front.

 

[Hib Halverson]

Been watching this thread develop for a week or so and you're getting nowhere fast.

Do you have the Factory Service Manual for your 2000?

If so, have you reviewed the information in Vol. 1, pg 5-26 and 5-27 which is the diagnostic info for brakes dragging?