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  • CJ-7 Brake Problem

    I'm doing a complete restoration of a 78 CJ-7. I've run into a real problem with the brakes. I have no pedal even after power bleeding the brakes. The pedal goes about half way to the floor, then stops solid. The rear drums seem to be working, but the front discs won't work at all. When I open the rear bleeders, the pedal goes to the floor. When I open the front bleeders, the pedal stops half way down.
    I've been through 3 master cylinders and 2 proportioning valves. I even installed a YJ power brake booster and Master cylinder. All lines are new. All new brake parts. I am at a loss for any other things I can do. Any help would be greatly appreciated.

  • #2
    Did you check the lines to see if they were clear first?

    Since you already replaced most of the stuff and get the same problem then maybe something in your system is messed up. Do you have the MC connected to the Combination valve correctly?
    I'm gonna have to think what might happen if you reverse the front and rear lines.

    What I'm thinking is that there is a safety valve in the combination valve that probably slides over and cuts off the pressure to the front brakes when you try to belled your brakes. I'm not sure how you bleed your brakes but I like to pump up slowly and make sure the pads and shoes contact their respective surface, that way it seems to help keep the safety valve centered. Is your brake warning light on? Are the wires connected?

    http://www.dana60.com/76cj5/provalve.jpg

    Technically there is a special screw that is inserted in place of the brake warning switch. This keeps the safety valve centered when bleeding the brakes. You might need one of these. Have to do a search or call Vanco Brakes and see if Van has one.
    Last edited by John Strenk; 05-15-2006, 06:49 AM.

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    • #3
      Same here dude on a cj7 '78

      John Strenk, you mentioned the brake lines being reversed. when I replaced my MC, thinking it was a problem because it was leaking anyways. I noticed that the small section and large section were reversed from my original '82 brake system MC.

      That was bugger, because I had to re-bend my brake lines to fit. I've got the back brake lines going to the small section, and my front going to the big section.

      Is that correct from what you know?

      I've having the same problem as described here. I can bleed my brakes in the back. everything fine. from the front, when i try, i just get a little bit out, then it stops.

      I don't have the 'special' tool that the manual says to somehow either pull or push in the 'metering valve stem', so is what I decribe here similar?

      Is the key to bleeding the front brakes getting that tool and somehow either pushing in or pulling out on the metering valve stem?

      I'm really getting ticked that a simple bleeding of the brakes for pressure, ends up with a lot of extra work. O' for the simplier days when everything was unsafe and one set of lines back and forth.

      Any suggestions or comments, would also be appreciated.

      Thanks o' knowledgeable ones out there.

      Comment


      • #4
        CJ Brakes

        I've tried and checked everything you guys have suggested. I even tried all YJ stuff (Proportioning valve, booster, and Master cylinder). I'm at a total loss.

        Comment


        • #5
          6 bolt calipers or two? 6 bolts carry more fluid than the 2 bolts and the brakes are and inch bigger than any other CJ both front and back. I could not do the YJ conversion with mine. The master return spring was not stong enough to return the fluid to the reservior. I ended up putting a master power brakes setup which really works well.

          http://www.mpbrakes.com/products/pro...product_id=144

          Then some kind soul researched it one better and found this.....which looks like the same thing to me, with a much better price.

          http://piratejack.net/power_brake_unit_text.html

          I used the proportioning valve from www.inlinetube.com which seems to work well to. There is another brake thread on here that gives the exact link if you need it.

          Check and see if you are have a 6 bolt configuration. Disks up front, drums rear.

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          • #6
            Thanks gnarly.

            I have the 6 bolt caliper on mine. That must be it. Have you ever tried non-power brakes? That's what was originally on mine, but it was undriveable when I got it, so I never got to see if they were adequate.

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            • #7
              Mine originally had manual brakes, and I have driven one with "good" manual brakes (NOT MINE) and they are OK. The master pwr brakes setup gives you "new car" confidence braking. My opinion anyway. I went through a similar....very long....drug out.....expensive.....humbling.....experience with my brakes and it sounds like you may be equaling it. I replaced every part on it, except the steel lines themselves, most of them two or three times. I did the YJ booster too, and messed with that adjustment between the booster and the master for HOURS. I feel your pain. FYI, I have heard if you drain fluid from one side of the proportioning valve and attempt to work the brakes with the bleeder open, it will do what its supposed to and cut off pressure to which ever side you drained. Slamming your foot on pedal really hard a few times often free's the proportioning valve if you get no pressure on the front or the back. This is really obvious when it happens....you'll get just a trickle from the bleeder when you open it. Just something to concider after you figure out the master issue.

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              • #8
                what about a one bolt caliper?

                Good information here, 'cept I have a one bolt caliper. It's a retaining screw to a slide bar, which when you take out the screw, tap out the slide bar and the calipers in the front just tip on out. really easy once I read how to get the part apart.

                On my 78 & 82 buildout. I took the 78 front end disk brakes, and rear 11 inch rear brakes (all new parts), and kept the proportionate valve that came with it, and switched out the manual MC with the Power Booster/MC from the 82.

                I can bleed the back fine, but again the front just gives me a trickle. What does anyone know about the 'special tool' that is mentioned on the two types of proportionate valves. in the '82 manual i have it mentioned that on the metering valve on one, you pull out while bleeding, and the other you push in while bleeding.

                I'm not sure which I have, or what type of tool is needed.

                Anyone messed with this 'metering valve' that can share their experiences/guidance?

                Thanks.

                Comment


                • #9
                  Originally posted by bigdaddy
                  Good information here, 'cept I have a one bolt caliper.
                  He means the caliper bracket, the CJ's had two different ones. The bracket is held to the outer knuckle by either 6 bolts or 2 bolts.


                  Scrambler

                  Comment


                  • #10
                    Good information here, 'cept I have a one bolt caliper. It's a retaining screw to a slide bar, which when you take out the screw, tap out the slide bar and the calipers in the front just tip on out. really easy once I read how to get the part apart.
                    you have the 6 bolt caliper like this
                    http://img.photobucket.com/albums/v1...1/302e0b8d.jpg
                    http://img.photobucket.com/albums/v1...1/102_0222.jpg

                    Comment


                    • #11
                      I can bleed the back fine, but again the front just gives me a trickle. What does anyone know about the 'special tool' that is mentioned on the two types of proportionate valves. in the '82 manual i have it mentioned that on the metering valve on one, you pull out while bleeding, and the other you push in while bleeding.

                      I'm not sure which I have, or what type of tool is needed.

                      Anyone messed with this 'metering valve' that can share their experiences/guidance?

                      Thanks.[/QUOTE]


                      I have not been able to locate the tool you are talking about, however, as I mentioned in the previous post to 14/88 you can free the "metering valve" by slamming the pedal really hard several times with quick releases. As the master recovers the fluid it often free's the valve. What you are describing is definately a proportioning valve issue and you will know when you've freed the metering valve. Mine did it on the rear.

                      Comment


                      • #12
                        Thanks again gnarly. Lots of great info. I'll be in the garage all nite now...

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                        • #13
                          Originally posted by 14/88
                          Thanks again gnarly. Lots of great info. I'll be in the garage all nite now...

                          Let us know how it goes. I'd love to hear if your 6bolts work with the YJ booster (as mine did not). Sounds like your first thing is to free the proportioning valve.

                          Comment


                          • #14
                            Two bolt calipers are simular.
                            THese are '79 disk brakes. You can see one of the two screws in the picture.
                            http://www.luanjp.com/strenk/images/...perTopView.jpg

                            You could probably make a valve stop pretty easy.
                            Just get a brass plug with a straight taper and drill and tap a hole for a screw. THen just remove the switch and screw in the plug and run the screw down into the notch in the valve. Use a strong screw. You would not want to shear off the end.
                            http://www.luanjp.com/strenk/images/.../ValveStop.jpg

                            Unfortunatly the valve has to be centered to begin with.

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                            • #15
                              Gnarly
                              Empty your private message mailbox. Sheeeeesh.

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