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brake problem, what gives? UPDATED 2

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  • brake problem, what gives? UPDATED 2

    I've been having a brake issue ever since switching to 88t rotors up front. The brakes work, but the pedal feel is REALLY Mushy, to the point where, if you really stand on them, you can hit the floor. They really don't pump up. I've replaced the master (with the one off the 88t parts car), thinking this was the likely cause, but even after bench bleeding, breech bleeding, and bleeding a quart of fluid out of the calipers, I'm still leaft with a fat-puppy brake pedal. I bled in the correct order, too. They never used to be this way, what gives?

    I assume there is still air in the system, by the way they feel. Am i missing something here?

    I'm considering having it flushed and powerbled by a local brake shop, but i want to be sure before i spend $55 on it.
    My beloved Z:1987 2+2 NA2T w/30a swap.
    My black sheep: 88ss parts car (pretty much stripped and gone)
    207k miles and counting. Turbo'd since 155k.

  • #2
    what type of fluid are you using? if you have dot 3, 4 or 5.1 fluid and there are no leaks then you still have air in the system somewhere..

    Comment


    • #3
      you could have a ballooning hose...also possibly a second bad master

      1987 Nissan 300ZX Turbo (Budget Supercar)
      1987 Nissan 200SX SE (Old School FR)
      1994 Nissan Sentra SE-R (Balls To The Wall Track Car)
      2000 Nissan Maxima SE (Daily Driver)
      2006 Scion tC (Wife Whip)

      In an ideal world I would have all ten fingers on my left hand, so my right hand could just be a fist for punching.

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      • #4
        Taris Blue wrote: you could have a ballooning hose...also possibly a second bad master
        good point, ill second that.. ive installed rebuilt masters that have been bad..

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        • #5
          I guess I'll check again to make sure no lines are ballooning first. Then tomorrow I'll have them do the power bleed thing to eliminate air as being a problem. If I still have a loaf of crap, new MC it is.

          to answer the question, yes, DOT3

          Edit: change of plans. I just found out my father was nice enough to run this master through the parts wash. No wonder it blows donkeys. Let's hope I can acquire and install a new master by the 7th.
          My beloved Z:1987 2+2 NA2T w/30a swap.
          My black sheep: 88ss parts car (pretty much stripped and gone)
          207k miles and counting. Turbo'd since 155k.

          Comment


          • #6
            How are you bleeding your system?

            Terrible idea putting those wheels on...

            Comment


            • #7
              Az4u2c wrote: I guess I'll check again to make sure no lines are ballooning first. Then tomorrow I'll have them do the power bleed thing to eliminate air as being a problem. If I still have a loaf of crap, new MC it is.

              to answer the question, yes, DOT3

              Edit: change of plans. I just found out my father was nice enough to run this master through the parts wash. No wonder it blows donkeys. Let's hope I can acquire and install a new master by the 7th.
              before you buy a new one take the master apart and clean it out really good.. make sure it is dry, and assemble it with some brake fluid as lube.. then bench bleed it and try it again.. dont let it get to you.. ive done a lot of brake bleeding in my life and for some reason ive always found that it required more effort to get all the air out of a z31..

              Comment


              • #8
                would someone mind explaning to me what exactly bench bleeding is and how it is done? and if it won't already make sense, why do it?

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                • #9
                  casner wrote: would someone mind explaning to me what exactly bench bleeding is and how it is done? and if it won't already make sense, why do it?
                  when you bench bleed a master you just fill it with fluid while its outside the car and manually pump fluid through it. maybe someone else can give a technical explanation as to why it is required, but i can tell you, unless you bench bleed a new master you will have a spongy pedal.

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                  • #10
                    z

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                    • #11
                      zmech wrote: I would replace the MC. I would imagine that it is bad. Not a very good idea to put in used parts into the brake system.
                      This is the conclusion i reached. I know that master wasn't too whoopy lookin' when it was removed, and sitting in a parts washer full of diesel for a week didn't do it any favors. I think if air was my only problem, the pedal would eventually get stiff when pumped repeatedly. It gets firmer breifly, but if you stand on it it slushes slowly to the floor. They have been getting me around okay street driving since I'm never on them hard or for very long. I ordered a new one, I'll throw it in next week or this weekend if it's here in time. Then I'll have them force-flushed at a local place if my own bleed job doesn't inspire confidence.
                      My beloved Z:1987 2+2 NA2T w/30a swap.
                      My black sheep: 88ss parts car (pretty much stripped and gone)
                      207k miles and counting. Turbo'd since 155k.

                      Comment


                      • #12
                        [quote]zmech wrote: [quote=Chris86NA2T]
                        Originally posted by casner
                        would someone mind explaning to me what exactly bench bleeding is and how it is done? and if it won't already make sense, why do it?
                        when you bench bleed a master you just fill it with fluid while its outside the car and manually pump fluid through it. maybe someone else can give a technical explanation as to why it is required, but i can tell you, unless you bench bleed a new master you will have a spongy pedal.
                        This is not the case at all. Bench bleeding simply get fluid into the master cylinder. However, as soon as you remove the fluid from the master to install it, you have just done the same thing as you would have if you just put it in and start to bleed.

                        Put in the master cylinder, fill with fluid, open up all the bleeders on the calipers and let them start to drip out till you get new fluid to each one. Then start to bleed them properly. Has worked every time for me. Maxima, Pathfinder, Z32, Z31 and Wilwoods. BTW: You can open one at a time if you like but it is quicker to let them all drip at once. I find the best way to bleed is also the old fashion way. One person pumps and holds and the other opens the bleeder. OR, use speedbleeders.

                        I would replace the MC. I would imagine that it is bad. Not a very good idea to put in used parts into the brake system.
                        bench bleeding is exactly as i described. read any service manual for almost any car and they will explain the same procedure in a bit more detail of course.

                        Comment


                        • #13
                          zmech wrote:

                          This is not the case at all. Bench bleeding simply get fluid into the master cylinder. However, as soon as you remove the fluid from the master to install it, you have just done the same thing as you would have if you just put it in and start to bleed.
                          You will never get all of the air out of the system unless you bench bleed the master...(note: Bench bleeding can be done when installed in the car as well, before hooking up the lines.) There can sometimes be a LOT of air in those masters...takes a good 5 min to get it all out...you'll never get it all out using a standard method of bleeding.

                          1987 Nissan 300ZX Turbo (Budget Supercar)
                          1987 Nissan 200SX SE (Old School FR)
                          1994 Nissan Sentra SE-R (Balls To The Wall Track Car)
                          2000 Nissan Maxima SE (Daily Driver)
                          2006 Scion tC (Wife Whip)

                          In an ideal world I would have all ten fingers on my left hand, so my right hand could just be a fist for punching.

                          Comment


                          • #14
                            [quote]Taris Blue wrote:
                            Originally posted by zmech

                            This is not the case at all. Bench bleeding simply get fluid into the master cylinder. However, as soon as you remove the fluid from the master to install it, you have just done the same thing as you would have if you just put it in and start to bleed.
                            You will never get all of the air out of the system unless you bench bleed the master...(note: Bench bleeding can be done when installed in the car as well, before hooking up the lines.) There can sometimes be a LOT of air in those masters...takes a good 5 min to get it all out...you'll never get it all out using a standard method of bleeding.
                            Yes of course. I fill the resevour, pump some fluid through it, bolt it on the car, one more pump, attach lines, then with the bleeder valves shut i burp the individual lines on the master 'till they're all wet. Then I move out to the wheels. Rear drivers, then counter-clockwise like the book says.
                            My beloved Z:1987 2+2 NA2T w/30a swap.
                            My black sheep: 88ss parts car (pretty much stripped and gone)
                            207k miles and counting. Turbo'd since 155k.

                            Comment


                            • #15
                              [quote]Az4u2c wrote: [quote=Taris Blue]
                              Originally posted by zmech

                              This is not the case at all. Bench bleeding simply get fluid into the master cylinder. However, as soon as you remove the fluid from the master to install it, you have just done the same thing as you would have if you just put it in and start to bleed.
                              You will never get all of the air out of the system unless you bench bleed the master...(note: Bench bleeding can be done when installed in the car as well, before hooking up the lines.) There can sometimes be a LOT of air in those masters...takes a good 5 min to get it all out...you'll never get it all out using a standard method of bleeding.
                              Yes of course. I fill the resevour, pump some fluid through it, bolt it on the car, one more pump, attach lines, then with the bleeder valves shut i burp the individual lines on the master 'till they're all wet. Then I move out to the wheels. Rear drivers, then clockwise like the book says.
                              i didnt realize you have aused master.. that has to be the problem.. bench bleed and install the new one and i bet your brakes will be fine.. good luck

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