I changed my brake pads and brake fluid 4 months ago. When I changed the fluid, I let the fluid get too low in the master cylinder. I bleed the system for about 2 hours trying to remove all the air. I thought that I had but I have to bleed the system every week just to get the brakes to not go all the way to the floor. I only need to bleed the front drivers side and the rear passenger side. There are no noticeable leaks.
This week, I took the van to my mechanic who bleed the brakes again and said they were good. I picked it up a couple hours later and the brakes had to be pushed all the way to the floor again. He said contact Chrysler and check for any ABS recalls. He said it could be the Master cylinder but he said these don’t fail often.
Do you think that there is somehow still air in the line from 4 months ago? Would a bench bleed help at this point? Do you think the Master cylinder is bad or brake caliper?
Thanks
Sometimes when you’re bleeding the brakes with an old master cylinder, and you let the pedal travel farther than it usually does, the seals in the master cylinder pick up gunk that’s built up on the inside wall of the cylinder. That gunk then prevents the seals from sealing properly. The only solution is to rebuild the master cylinder, or replace it.
Bleeding brakes on cars with ABS and stability controls just isn’t that easy. The process can differ car by car. I think your cheapest option at this point is to replace the master cylinder yourself. Then take the car to a Chrysler dealer to have the brakes bled properly.
I’m assuming you and the mechanic have ruled out all leaks and defective caliper(s). Replacing the master cylinder should do it, but I’d have Chrysler bleed the brakes just to be sure. You don’t want to mess with brakes that could be below par.
how many miles on this van?
although i would completely bleed them again, it does sound like the MC has been letting air get sucked in.
have you in the past replaced the MC? my method of bleeding brakes involves using a long piece of plastic hose (buy at any hardware store) get it to just fit over the bleed screw. then crack the screw and pump the fluid all the way up to the reservoir (no more empty reservoirs!) right rear, left rear, front right, front left. using a clear hose you can actually see the air bubbles and know when you have finished bleeding that particular caliper. i don’t think you can properly bleed a whole system by just doing one or two calipers. you have to do all 4.
if this keeps getting air in it, then you have another problem. have you noticed any leaks around any brake cylinders? if you dont see ANY leaks out, then there is likely NO leaks of air in either. Then i would suspect the MC.
Basides air in the line that could cause a weak brake peddle, so too could a out of adjustment parking brake. Does the parking brake work properly?
Thanks to you all for your replies. I replaced the replaced the front drivers caliper at the recommendation of an autoparts store. It was cheaper and easier than the MC replacement and hoped that it would work but was disappointed. Strong pedal for about a day and then started getting air. Over the next few days, the pedal is now at the floor.
There were/are no noticeable leaks. The fluid in the reservoir never drops at all. I assume that I did as shadowfox said and pump gunk into the seals by pushing the pedal too far.
to cappy208- 110k miles, no noticeable leaks out
americar- the parking brake seems like it could be stronger but does that matter since the car has rear disc brakes?
Thanks again,
Shawn
If air got into the M/Cyl you may have to “bench bleed” it…
Update…
Replaced the Master Cylinder last night (after bench bleeding). When attempting to bleed the brakes, I was unable to get any fluid or air from the driver’s front and passenger rear. The other two move a little fluid but not much. The other problem is that the new master cylinder seems to not recoil after pressing down. If I try to press the pedal down again within 10 seconds, the peddle drops half way or more before engaging the MC. The brakes are not at all functional and this is much much worse than before.
It seems the only thing left to replace is the ABS module. I was hoping this was not the case due to cost. Is this something I can do myself? What about purchasing a used module? Any other ideas?
Thanks
If the master cylinder lines are removed and the outlets plugged, several pumps on the pedal should get the air out and the pedal should be rock hard and at the top. Try that. If the pedal is low and soft remove one of the plugs and try the pedal. If no change reinstall that plug and open the other outlet. Pump the pedal again to get the air out of that circuit and try the pedal. One end of the master cylinder may be bypassing. You must isolate the problem.
The brakes on an ABS equipped Town and Country with air in the lines have to be bled by someone who has the right equipment to input the right codes to the ABS to keep the valves in the ABS open during the process. Usually it is the dealer and they charge $200 to bleed the brakes in my area.
This is the bleeding procedure for your vehicle. Bleeding the base hydraulic system does not require any special tools for the ABS system.
STANDARD PROCEDURE - ANTILOCK BRAKE SYSTEM BLEEDING
The base brake’s hydraulic system must be bled anytime air enters the hydraulic system. The ABS though, particularly the ICU (HCU), should only be bled when the HCU is replaced or removed from the vehicle. The ABS must always be bled anytime it is suspected that the HCU has ingested air. Under most circumstances that require the bleeding of the brakes hydraulic system, only the base brake hydraulic system needs to be bled.
It is important to note that excessive air in the brake system will cause a soft or spongy feeling brake pedal.
During the brake bleeding procedure, be sure the brake fluid level remains close to the FULL level in the master cylinder fluid reservoir. Check the fluid level periodically during the bleeding procedure and add DOT 3 brake fluid as required.
The ABS must be bled as two independent braking systems. The non-ABS portion of the brake system with ABS is to be bled the same as any non-ABS system.
The ABS portion of the brake system must be bled separately. Use the following procedure to properly bleed the brake hydraulic system including the ABS.
BLEEDING
When bleeding the ABS system, the following bleeding sequence must be followed to insure complete and adequate bleeding.
Make sure all hydraulic fluid lines are installed and properly torqued.
Connect the DRB III scan tool to the diagnostics connector. The diagnostic connector is located under the lower steering column cover to the left of the steering column.
Using the DRB, check to make sure the CAB does not have any fault codes stored. If it does, clear them using the DRB. WARNING: WHEN BLEEDING THE BRAKE SYSTEM WEAR SAFETY GLASSES. A CLEAR BLEED TUBE MUST BE ATTACHED TO THE BLEEDER SCREWS AND SUBMERGED IN A CLEAR CONTAINER FILLED PART WAY WITH CLEAN BRAKE FLUID. DIRECT THE FLOW OF BRAKE FLUID AWAY FROM YOURSELF AND THE PAINTED SURFACES OF THE VEHICLE. BRAKE FLUID AT HIGH PRESSURE MAY COME OUT OF THE BLEEDER SCREWS WHEN OPENED.
Bleed the base brake system using the standard pressure or manual bleeding procedure.
Using the DRB, select ANTILOCK BRAKES, followed by MISCELLANEOUS, then BLEED BRAKES. Follow the instructions displayed. When the scan tool displays TEST COMPLETED, disconnect the scan tool and proceed.
Bleed the base brake system a second time. Check brake fluid level in the reservoir periodically to prevent emptying, causing air to enter the hydraulic system.
Fill the master cylinder reservoir to the full level.
Test drive the vehicle to be sure the brakes are operating correctly and that the brake pedal does not feel spongy.
Update. Decided that the new MC had to be malfunctioning. Replaced it and the new, new MC at least springs back with the pedal.
Now, I am having new problems. The pedal is very firm at the top but requires a lot of pressure to push down to get the van to stop… but at least it stops. I am not sure if this MC is good. When I swapped the other MC out, this new one was opened and didn’t include manuals or the rubber boot. I was told to take the boot from the other MC. This one might be a customer return for some reason. Figure I will try replace the MC once more (lifetime AZ warranty) and then thoroughly bleed. If this fails, off to the dealer.
Again, remove the brake lines from the master cylinder and plug the outlets. After several pumps to displace the air, the pedal should be HIGH and HARD and remains high for a minute of sustained pressure the master cylinder is OK. Once you are certain that the master cylinder is working properly check the booster, thusly; wrap the vacuum line to the booster with a shop rag and pinch it with locking pliers to stop all vacuum flow. Start the engine and pump the brake pedal several times and hold the pedal hard while an assistant releases the pliers. The pedal should move somewhat lower and when pumped have less resistance.
Update. Finally took my van into the Chrysler dealer. They tried to rebleed the entire system. They keep getting air from the driver’s front caliper. Look it up in their database and diagnosed as a bad ABS actuator. They want $702 for parts and labor.
I found several used ABS actuators at junkyards for $90. Of course the dealer said that I would be responsible for the labor if the used part were bad. I am thinking about replacing it myself and taking it to a shop to be bled since I don’t have the scan tool and don’t have $6,000 for buying one. Any thoughts?