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Thread: Symptoms of bad master cylinder ?

  1. #1

    Default Symptoms of bad master cylinder ?

    My moms car, 99 NB 5 speed.

    Today she tried to start the car and the clutch pedal went straight to the floor i assumed it was the slave cylinder since the same thing happened in my 99 and my friends 90 NA. i changed it out and tried bleeding the clutch i had it bled pretty good and when we turned it on we couldn't get it into gear.

    The master cylinder doesn't look to be leaking is there any other way it can be bad? her clutch reservoir was full even before i changed the slave cylinder and this happened over night the car was driving fine yesterday

    Any suggestions ?

  2. #2
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    Master cylinders can fail internally. Seals go bad and fluid starts leaking around them. Don't know if this is your case, but it can happen. A quick observation under the car to see if the slave is actuating when the pedal is pressed might help enlighten.

    Regards.

    ps. Don't completely rule out air in the line even though you've bled it already. Checking twice can never hurt.
    Last edited by Piff; 09-27-2011 at 10:25 AM.

  3. #3

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    How did the clutch feel after bleeding? When I changed out my slave, did the bleeding and everything my clutch was still jacked. I changed the master, filled and bled and everything worked fine after that. My slave was leaking but the master looked fine. I can only speak for me but it was almost like the needed to be changed together.
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  4. #4

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    Quote Originally Posted by Piff View Post
    Master cylinders can fail internally. Seals go bad and fluid starts leaking around them. Don't know if this is your case, but it can happen. A quick observation under the car to see if the slave is actuating when the pedal is pressed might help enlighten.

    Regards.

    ps. Don't completely rule out air in the line even though you've bled it already. Checking twice can never hurt.
    That's the thing, On hers after i changed the slave when she depresses the clutch i see barley any movement at all, on my 99 when i press the clutch in my slave cylinder moves in about and inch or two, i can tell mine moves alot more when depressing the clutch.

    Is it normal to see bubbles in the master cylinder reservoir while pumping the clutch with the fluid full ? or is that indicating a problem within it self ?
    I find it weird that her clutch went to to floor with the fluid completely topped off like its not leaking from anywhere.

  5. #5

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    Quote Originally Posted by titanescape View Post
    How did the clutch feel after bleeding? When I changed out my slave, did the bleeding and everything my clutch was still jacked. I changed the master, filled and bled and everything worked fine after that. My slave was leaking but the master looked fine. I can only speak for me but it was almost like the needed to be changed together.
    I got it to bleed to where it felt tight once we turned on the car it wouldn't go it to gear. then i changed the slave cylinder, bled again, and same thing, pressure will feel good but when the car is on still cant get the car into gear.

  6. #6

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    If the slave doesn't move and you see bubbles I'm thinking it is time to change the clutch master.

  7. #7

  8. #8

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    Quote Originally Posted by POS Racing View Post
    Yeah i was reading over that and still wanted to make sure the master was bad before i changed it out, i guess ill try that and let you guys know what happens

  9. #9

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    You need to pull a vacuum on the line (something like a mighty vac brake bleeder) as the system has some uphill spots. I changed my master cylinder and it was completley empty from there to the slave. Couldn't bleed it to save my life. Finally pulled a vacuum on it with a large syringe and it finally bled.

    Also look under the dash where the master cylinder mounts to the wall and see if you have a leak there while pressing the pedal. Mine was leaking into the car and I didn't realize it till I was down there messing with something else.
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  10. #10

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    If the seals are bad in the master it will let fluid slip past the seals. No external leaks just internal leaks. And that sounds like what you are experiencing.



    Although with 2 NB's and 2 NA's I've never had to replace a slave master but I do stock a rebuilt Clutch Slave Cylinder in my garage at all times.

  11. #11

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    Quote Originally Posted by POS Racing View Post
    If the seals are bad in the master it will let fluid slip past the seals. No external leaks just internal leaks. And that sounds like what you are experiencing.



    Although with 2 NB's and 2 NA's I've never had to replace a slave master but I do stock a rebuilt Clutch Slave Cylinder in my garage at all times.
    So you think the internal leak is causing the bubbling from the reservoir ?

  12. #12

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    Quote Originally Posted by NissanFairladyZ32 View Post
    So you think the internal leak is causing the bubbling from the reservoir ?
    Or possibly Sea Monkeys.

    There are only 2 moving parts in the entire system and you've already replaced one.

    As Jeepinbanditrider mentioned it you may not have the system compleatly free of air if it's not air in the system it could be the slave master cylinder.

  13. #13

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    Thanks ill keep you guys updated on the fix.

  14. #14

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    Another quick thing to look at is the hose itself. Had a failure on my wife's '02.



    Here is the rest of the story - http://www.dfwmiata.com/showthread.p...ht=Vivid+Slave

  15. #15

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    Bought and installed a new master cylinder for $20 at orileys and the car is going into gear better then ever says my mom,

    After installation of the master cylinder it bled really nice within 2 minutes had all the air out of the system, with the bad one i couldent get it to bleed right was bleeding it for over an hour and not firm enough pressure.

    thanks for all the helped, i hope this thread helps someone in the future with the same problem, my advice is to change the master and slave at the same time its $40 total and will save you time.

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