Hey all - I have a '97 Caravan, 3.3 L motor, 160k miles. Runs great, but I gotta have brakes...back in July, I changed the front pads & had rotors resurfaced. After 3-4 days, the brake pedal was 'spongy' & would go to the floor. OK, gotta bleed the brakes. Bled air off of them, everything was kosher..for 3-4 days again. Bled them again, ran it OK, lost driver front wheel @ 70 MPH due to inadequate torque on rim remount on most recent bleed job. OOPS. Didn't roll it. Replaced factory rim & tire, rebalanced & aligned front end & bled brakes. OK for 3-4 days, then sponge city. Got fed up, had REAR wheel cylinders replaced, rear hardware kits, new shoes & resurface on drums. Also had to replace rear steel lines to wheel cylinders - they were rusted into cylinders & broke when trying to remove from cylinders. Still taking on air, so I replaced the master cylinder. Still taking on air, so I replaced the front flex lines to the calipers. Still taking on air - just replaced Frnt. Drvr caliper Sat. AM & didn't change problem.

I have now replaced EVERYTHING in the brake system EXCEPT the Pass. caliper, the booster, and the lines from the master cylinder to the mid-frame & down to the start of the flex hoses. It still takes on air, there is no visible leakage anywhere, and I've now been fighting this one for 3 months. Maybe power assist booster, but builds & holds pressure @ pedal when engine off; once started, the brake pedal falls completely to the floor, and will not hold pressure....no amount of bleeding seems to rectify the situation. Once it sits for 3-4 hours after bleeding, the air is in the lines again.

Any suggestions? I don't see how air could be leaking into the lines from a faulty booster - it shouldn't happen - but I'm willing to replace the booster myself if it'll finally fix the problem. Any suggestions would be appreciated much.

Thanks -

James Ricks

 

Do you have ABS?If so you could have air in the system that can't be removed using regular bleeding techniques.I've been lucky and have never gotten air into an ABS system so I don't know what the symptoms might be.

 

GAWD - I hope it isn't that - sounds like an absolute joy to rectify....James

 

...finally got to the bottom of the problem - the ABS cylinder was FULL of air, necessitating a software tweak to open up the ABS solenoids & bleed &n refill the COMPLETE system. Pro'bly happened by letting the fluid level drop too low when bleeding the mains, then having to stomp on the pedal to actuate the ABS when the main bleed job didn't get all the air out.

Moral of the Story: If you do a mains bleed job on a system with ABS, make damn sure you're topped off at all times. I wound up taking it to a garage that had the diagnostic handheld & the software to insure that ALL air was out of the WHOLE system, not just the mains. after all I replaced on it & after paying roughly $100 to have the ABS refilled & bled, I'm not gonna need brake work for a while now...

Thanks all for your input - you guys rock!

--J

 

When you serviced the brakes assuming its equipped with ABS, you must bleed the brakes in the proper sequence otherwise you will always have problems. This is due to the proportioning valve(s) and the ABS system. Bleed the brakes in the proper sequence as per a Haynes or Chilton manual.

 

What is the proper order to bleed ABS Brakes ?