HELP MY 2002 Dodge Grand Caravan SE with a 3.3L auto ABS the master cylinder was replaced 3 times also the system was bleed several times the brakes peddle keep going all the way to the floor after about 2 days of driving.

 

Did you bench bleed the master cylinder before installing it? If not, you'll NEVER get the air out. Also, you may have air in the ABS system. Only two ways to get it out:

Read this:

http://www.ricksfreeautorepairadvice...-an-abs-system

 

A few weeks ago, the brakes went to the floor with slow stopping. The shop said that I needed front pads and master cylinder. $500. the brakes felt fine. For a few days. Problem came back.

Shop replaces master cylinder again. Things are fine - for a few days.

Shop bleeds front drivers wheel only. Things are fine - for a few days.

Shop declares that I need to replace the ABS controller.

Any other thoughts? I really appreciate the help. School is starting and we really need this van to be operational!

 

not the controller the ABS HCU (the hydraulic control unit).

 

Any resolution to this? We are having the same problem on our 2002 GC. LF caliper was replaced, Master Cylinder was replaced. (This was before I started work on it, so I don't know the details)

Sometimes the pedal will stay firm for a few months, sometimes for a couple of days. I have bled it with a Snap-on Solus Pro and when I went to manually bleed the LF, the first two strokes was nothing but air. After that it has never been a perfectly clear stream. I have a clear hose hooked to the bleed screw and can see very fine air bubbles in there like the fluid is frothy. Is this a normal consequence of the scanner bleeding?

I need to try this again without the driver waiting for me so I can go through all four corners. I am thinking to start with the scanner, do all four corners, do the scanner again, then do all four corners again.

I have inspected the system and have found no leaks, but can the HCU have an internal leak allowing air in but not fluid out?

 

When you bleed the base brakes, bleed as normal. But when using a scanner, you don't open the lines. The HCU will force bleed the air out of the system.

 

There are some problem with the HCU creating Air pocket in the Front calipers on the minivan. If after driving a while, pedal sink to floor and found air in the Front caliper, replace the HCU.

Case Number999926969 Vehicle IssueLow Brake Pedal. Has Air In Left Front Caliper.;97 - 2000 NS, 2001 - 2005 RS vehicle equipped with ABS. Not equipped with traction control. Air only in left front caliper.System or ComponentLow / Spongy Pedal;Customer Concern (No DTCs);Base BrakesRecommendationReplace the hydraulic control unit.
Modification Date09/20/04 7:35 AM



Pesonally, I seen this twice and fixed with an HCU.

 

Right. Unfortunate wording of mine.

Steak59 seems to be onto something though.

 

Steak, thank you for the info, but I'm not sure what it is that you quoted. It looks like a service bulletin or something, but I'm unsure.

 

I have never replaced an HCU before, are there any gotchas on this? I know that the Master Cylinder will want to drain, but I think I may be able minimize this by removing the lines and installing them so the ends are higher than the level, (I'll have to look) but is there a procedure to prefill the HCU or is that just done with a scanner? Maybe get everything hooked up except the outlet side and let it gravity bleed for awhile, then do the Scanner bleed?