Thread: 1994 ZJ ABS brake bleeding issues

Results 1 to 9 of 9
  1. #1 1994 ZJ ABS brake bleeding issues 
    Junior Member dragordie's Avatar
    Join Date
    Sep 2010
    Location
    North west Indiana
    Posts
    16
    Rep Power
    0
    Replaced rotors calipers brake lines fresh fluid. I have Bleed my brakes 5 times now 3 with my Vac and twice old conventional way 2 people. Still The driver side rear and driver side front will not bleed. Any ideas?? What is this about DBR tool. I don't have OBD data link connecter. That is its not on the pass side at or around the overflow tank.
    Reply With Quote  
     

  2. #2 Re: 1994 ZJ ABS brake bleeding issues 
    Senior Member Ken L's Avatar
    Join Date
    Jun 2004
    Location
    Arvada, CO
    Posts
    841
    Rep Power
    69
    "Will not bleed" meaning the air won't stop coming out or you're not able to crack open the bleeders? I've never needed a special tool to bleed the brakes on my '96, but after replacing lines I've had to bleed them a crap load of times to get all the air out. If I remember right, I had to leave it sit overnight to get all the air to settle to a couple of spots and then bleed it. Then I pumped the brakes like crazy until they were rock hard and cracked the bleeders, doing it the two-person method.

    Not meaning to be a Dick, but you're bleeding it passenger rear-driver rear-passenger front-driver front, right? There really shouldn't be a connection between the driver's front and driver's rear, two separate circuits.

    I'd also try unplugging the electrics to the ABS pump and starting again.
    Ken L
    '96 ZJ with stuff
    Reply With Quote  
     

  3. #3 Re: 1994 ZJ ABS brake bleeding issues 
    Senior Member Ken L's Avatar
    Join Date
    Jun 2004
    Location
    Arvada, CO
    Posts
    841
    Rep Power
    69
    Oh, one other thing I just thought of. If you replaced the fluid, did you bench bleed the master? Still shouldn't be a connection between the driver's front and rear, but if all the fluid came out the master needs to be bled first, before the rest of the circuit can be filled.
    Ken L
    '96 ZJ with stuff
    Reply With Quote  
     

  4. #4 Re: 1994 ZJ ABS brake bleeding issues 
    Junior Member dragordie's Avatar
    Join Date
    Sep 2010
    Location
    North west Indiana
    Posts
    16
    Rep Power
    0
    bench bled M/C broke open all bleeders gravity bleed. capped every bleeder off. started with the rear pass and drivers rear to front pass than driver. I get fluid from front and rear pass bleeders nothing but air from driver front and rear. even when power bleeding. Anyone just removed their ABS. I have 4 wheel disc brakes it is my DD / rock rig.
    Reply With Quote  
     

  5. #5 Re: 1994 ZJ ABS brake bleeding issues 
    Senior Member Ken L's Avatar
    Join Date
    Jun 2004
    Location
    Arvada, CO
    Posts
    841
    Rep Power
    69
    I haven't removed the ABS, all I did was unplug everything and took out the relay in the underhood power center. I haven't needed the room under the hood yet, but it's and option to remove the ABS mechanics in the future if I need to.

    Don't know what else to tell you. As I'm sure you're thinking, this shouldn't be that difficult.
    Ken L
    '96 ZJ with stuff
    Reply With Quote  
     

  6. #6 Re: 1994 ZJ ABS brake bleeding issues 
    Senior Member Grand Slam West Planner K2's Avatar
    Join Date
    Jun 2004
    Posts
    919
    Rep Power
    74
    I pulled my abs stuff. You will need to bend new brake lines to attach to the old lines.
    95 ZJ, Lift, dents, and noise.
    Reply With Quote  
     

  7. #7 Re: 1994 ZJ ABS brake bleeding issues 
    Junior Member dragordie's Avatar
    Join Date
    Sep 2010
    Location
    North west Indiana
    Posts
    16
    Rep Power
    0
    So if I remove all the ABS components I will also need to replace the M/C do to the fact I has 2 large like fuel lines from the M/C to the ABS pump. maybe 96 or newer M/C? and than add a T to the front lines to single to the M/C? and should be able to keep the original proportioning Valve do to have 4 wheel disc brakes
    Reply With Quote  
     

  8. #8 Re: 1994 ZJ ABS brake bleeding issues 
    Senior Member Grand Slam West Planner K2's Avatar
    Join Date
    Jun 2004
    Posts
    919
    Rep Power
    74
    On my 95 I think I got adapters for the master cylinder and used same size lines.
    95 ZJ, Lift, dents, and noise.
    Reply With Quote  
     

  9. #9 Re: 1994 ZJ ABS brake bleeding issues 
    Senior Member Lifetime Supporter
    GSSW Planner
    FearTheDentist's Avatar
    Join Date
    Jun 2005
    Location
    Chapel Hill, NC
    Posts
    405
    Rep Power
    62
    I ran into something very similar on my WJ, I imagine it’ll apply to a ZJ.

    First though- nothing but air from driver front and rear? If I understand what you meancorrectly then air must be getting in somewhere?

    In my case, my WJ sat for >1 year until I got around to swapping the motor. Once it was running again, the brakes were really really spongy. No matter how much I bled them it didn’t help, finally had a shop do it and they had no better luck. Replacing MC , booster, and calipers didn’t help. I finally removed the ABS module entirely (it’s been disconnected for 14 years anyway. It still was a pain to bleed fully, but it finally came around. I also swapped in a MC from a ‘79 grand marquis to better handle the larger callers I have (D60 and 14b), but assuming you have stock calipers you shouldn’t have to worry about anything like that.

    My best guess what was happening? If you get air in your abs module, you have to cycle it using a scanner like a shop will have- your home scanner can’t do it. If it’s not cycled, air can get trapped in the little pistons that normal bleeding won’t remove. I suspect that, after sitting so long, one of the pistons in the ABS module was seized with air trapped in it, so even though the shop did cycle it, it still has air in it. Side note- if one was stuck, wouldn’t shop computer pick that up? Dunno, but this was the best explanation I could come up with.

    As far as bypassing the ABS module- 2 lines out from MC to ABS, the rear line is for the front brakes, front line is for rear brakes- really important not to mix that up! The ABS module has 5 lines- 2 in, 1 out to each front wheel, and 1 out for the rear. Just disconnect all the lines, use a tee to connect your 2 front lines, then run a new line from the rear port on the MC to the tee. Cut the fitting off the rear line and replace with whatever size the front port on the MC is.

    I had to leave the ABS module connected or my speedo didn’t work. You could probably trace and splice the wiring to bypass it if you really want to take the thing out but it wasn’t worth the trouble to me.

    I got this flaring tool on Amazon- way easier to use than the common type for flaring lines in place on the vehicle (it’s really easy to use, just practice a couple of times first).
    https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1


    Keep in mind that all the other drivers on the road count on you to have working brakes- if you’re not 100% confident in your ability to do this, don’t take a chance on it.


    On a separate note- hey guys, been a while!
    Last edited by FearTheDentist; Today at 04:28 PM.
    2004 WJ 60\14b ARB\lockrite 37" Nitto mud grapplers

    Quote Originally Posted by SuicideTireZJ View Post
    If there's one thing I like more than Moab and Grand Cherokees, it's a little boy on boy action.
    Reply With Quote  
     

Thread Information
Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Posting Permissions
  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •