Ask The Expert- Bleeding the Brake Lines after Lift Install

Brian

Jeep Fanatic
We have a Jeep in our shop that a local gentleman tried to install his MetalCloak lift on in his driveway. He did everything correct, except the brake bleeding. He let the lines sit and drip for a week, allowing air into the master cylender. Then he did a normal brake bleeding prodedure with two people trying to get the air out.

At this point, he has very spongy brakes. We believe that air might be in the ABS system. We are using our motive power bleeder to correct this situation with no luck. This is not our first rodeo..... Is the Jeep system similar to Ford's where one can leave the key on doing brake bleeding and the ABS will cycle as fluid moves through the system with a power bleeder or so we have to have a computer to cycle the ABS?
 

Cloaked Willys

Jeep Fanatic

Brian

Jeep Fanatic
I alway use a pressure bleeder. It makes it easy to bleed the brakes if you can't find someone to help you and with ABS systems you don't have to worry about the system engaging. I included the link to the one I use. Best tool I ever bought. Saves time and frustration. I also bleed the system every couple years like I am supposed to now that it only takes 10-15 min.

https://www.motiveproducts.com/collections/domestic-bleeder-kits/products/chrysler-dodge-mopar-bleeder
We have the full premium Motive Power Bleeder with the aluminum connectors in our shop. The issue we have now, after using the Motive power bleeder is that we still have a soft pedal after bleeding 3 times. We have run 8 quarts of fluid through the Jeep trying to get out the air..... Our only guess is that we have air in the ABS since air was introduced well past the Master Cylinder.

So when you say do not worry about it, does that mean Jeep allowed you to bleed the ABS system without doing anything? With Ford, one has to either use a computer to cycle the solenoids or leave the key on to allow the car to do it as you bleed.
 

Cloaked Willys

Jeep Fanatic
I have always bleed the system with the key off using the pressure bleeder without any issue. Thankfully I have not had to deal with air in the ABS block.

Doing a little digging I did find this.

Here you go, straight from the JK FSM:


ANTILOCK BRAKE SYSTEM BLEEDING
The base brake's hydraulic system must be bled anytime air enters the hydraulic system. The ABS must always be bled anytime it is suspected that the HCU has ingested air.

Brake systems with 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.

NOTE: 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 Mopar® DOT 3 brake fluid as required.

BLEEDING
When bleeding the ABS system, the following bleeding sequence must be followed to insure complete and adequate bleeding.

1. Make sure all hydraulic fluid lines are installed and properly torqued.
2. Connect the scan tool to the diagnostics connector. The diagnostic connector is located under the lower steering column cover to the left of the steering column.
3. Using the scan tool, check to make sure the ABM does not have any fault codes stored. If it does, clear them.

WARNING: When bleeding the brake system wear safety glasses. A clear bleed tube (1) must be attached to the bleeder screws and submerged in a clear container filled part way with clean brake fluid (2). 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.

NOTE: Pressure bleeding is recommended to bleed the base brake system to ensure all air is removed from system. Manual bleeding may also be used, but additional time is needed to remove all air from system.
4. Bleed the base brake system. (Refer to 05 - Brakes - Standard Procedure)
5. Using the scan tool, select ECU VIEW, followed by ABS MISCELLANEOUS FUNCTIONS to access bleeding. Follow the instructions displayed. When finished, disconnect the scan tool and proceed.
6. 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.
7. Fill the master cylinder fluid reservoir to the FULL level.
8. Test drive the vehicle to be sure the brakes are operating correctly and that the brake pedal does not feel spongy.
 

Brian

Jeep Fanatic
Thanks! I was hoping it could be easier, like the Fords.

I would slap this guy if I could. Thanks for the help, we will have to get a scan tool for the Jeeps.
 

Pthorpe84

Moderator
Staff member
Good read. Thanks for the question and answers. This will be a great reference for future builds.


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