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Thread: JK ABS Bleeding W/O Scan Tool?
September 16th, 2010, 05:03 PM #1
JK ABS Bleeding W/O Scan Tool?
Before I submit my poor JK to the same dealer whose tech left the oil filter loose last time they serviced it, does anyone know how to bleed the ABS system without Chrysler's DRBIII Scan Tool?
September 16th, 2010, 06:12 PM #2
You can not do it with a DRBIII anyways,you need the StarScan for the JK.Otherwise there is not alot that can be done,you can try going out and slamming on the brakes hard enough to engage the ABS(need to do about 5-10 times) and then re-bleed on the spot as air will enter the ABS pump again if you drive back home.This has worked a few times on older ABS systems but never got it to work on newer ABS systems though.'02 KJ,SkyJacker lift,ARB in rear,Detroit TT up front,and a custom paint job.:P
September 16th, 2010, 06:15 PM #3
What exactly does the DRBII tool do during its routine? Is it possible to pressurize the MC and bleed the 6 lines right at the ABS unit?
September 16th, 2010, 08:34 PM #4
September 16th, 2010, 08:47 PM #5
Why ??????????2 OF THE VOICES IN MY HEAD SAY THE WORLD IS A BEAUTIFUL PLACE. THE THIRD KEEPS YELLING PULL THE TRIGGER.
EVERY TIME YOU KEEP YOURE MOUTH SHUT SO YOU DONT OFFEND SOMEONE YOU LOSE A LITTLE PEACE OF YOURE 1ST AMENDMENT RIGHTS !!!!!
September 16th, 2010, 08:49 PM #6
Unless you replaced the ECU/HCU its a sealed system
Just a normal bleed
Nornal bleed is with a vacuumm bleeder
September 16th, 2010, 09:21 PM #7
September 16th, 2010, 10:20 PM #8
September 16th, 2010, 10:37 PM #9
Per the JK FSM official factory bleed procedure for the service brakes is via pressure, not vacuum, but the latter would probably work ok. That has no effect on the ABS section, which unfortunately it appears has to be manually cycled by the scan tool to burp the solenoids and pump unit. I pressure bled about a gallon of fluid through the bloody thing and it had no effect on the mushy pedal. Crap...back to the dreaded dealer flat rate moneys.
September 16th, 2010, 10:40 PM #10
September 17th, 2010, 02:15 AM #11
Again, there is no need to pay the dealer to bleed the ABS. It's difficult at best to get air in the ABS, and it's not going to cause a soft pedal.
If you ran the reservoir low, bleed the master. You can bleed all day at the wheels and still have air trapped at the master.
Also, good independent repair shops have a bi-directional scanner than will run the bleed function of the ABS unit too. It's not all smoke and mirrors
Last edited by Digger; September 17th, 2010 at 02:19 AM.
September 17th, 2010, 07:24 AM #12
Good tip on the master cyl Diger. We'll try bleeding at the lines & see what happens.
Re: bleeding the ABS and bleeding in general, here's the official procedure 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 MoparŪ DOT 3 brake fluid as required.
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.
September 17th, 2010, 08:20 AM #13
The bleed function of the HCU simply consists of it cycling its pistons to purge air from itself. It does this while the hydraulic system is closed so, any air that is in the HCU enters the base system. That's what requires the second bleeding of the base system.
The only way air is able to get into the HCU is by being new/rebuilt, or, activation of the ABS with a lot of air in the base system. This is hard to do in itself as you would not have enough pedal pressure to be able to activate the ABS in the first place.
September 17th, 2010, 09:38 AM #14
Thanks, Digger, great explanation. After I put the lines on last year the ABS light came on momentarily, then went out and has never come back on. ABS seems to work fine, so I think your idea about the MC is the best place to look at this point.
September 17th, 2010, 10:31 PM #15
TRAIL HUGGER - Enuf said.
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September 18th, 2010, 05:57 AM #16
September 18th, 2010, 07:15 AM #17
September 18th, 2010, 08:55 AM #18
September 18th, 2010, 09:39 PM #19
Jerry, something to look into, does the ABS on the JK have a relay? If your taking it to Lance, maybe he could take the relay out and jump the terminals to activate and cycle the pump. Or if it is just a 12V motor on the pump, disconnect it and cycle it. I have been able to do this on my '05 Dodge before to check the fuel pump. Maybe also if you burn that thing to the ground you could start over AGAIN
Also, since you changed out the brakelines when this started, maybe there is one that is not sealing right and sucking tiny amounts of air in. I had a fuel injection system kick my butt one time because of this scenario. The stupid filter would not leak fuel, but it would suck massive amounts of air causing me a bunch of problems. Remember that Scout Buggy I had? I sold that sucker on the spot to a guy because the POS would not run. He took out the filter and bingo! It ran fine for him.My name is Daniel. I pretty much do what I want.
September 18th, 2010, 10:41 PM #20
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September 19th, 2010, 07:49 AM #21
Short of torching this SOB I'm just going to bite the proverbial bullet and let the dealer run the Starscan ABS routine on it. We'll see what happens. Other than when I changed the lines out it has never had any air come out when I've bled them and there's no sign of seepage anywhere. I was going to try pressurizing the system with the pressure bleeder and then cracking open the lines on the ABS unit but decided the thing would probably go into some kind of electro-seizure and need a tow truck.
September 24th, 2010, 07:25 PM #22
Had the local dealer run the Starscan ABS bleed routine on Wednesday. (The same one who always overfilled the oil on my Grand Cherokee, and left the filter loose on the JK last time I had them service it. I do it myself now.) I got it back and NO CHANGE. Yesterday I put the pressure bleeder back on for one more burp before I throw up my hands and shoot this SOB. Hmmmm...bubbles came out of the left rear...hmmm, bubbles came out of the right front...hmmm, pedal now seems fine.
D'ya suppose after the tech ran the Starscan ABS bleed routine he then bled the main system again like the book says to do, huh, like the procedure in the book THAT I PRINTED OUT FOR HIM SAYS TO DO?????!!!!! SHIT, NO!!!!!
Oh, well, I did what I could. At least I now have some brakes.