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Mondial - Master clutch (do I use it?)

Discussion in 'Technical Q&A' started by Mondy, May 16, 2009.

  1. Mondy

    Mondy Rookie

    Mar 27, 2009
    19
    England
    Full Name:
    Andrew
    Hi all Just got my Mondial QV back on the road and am struggling to get a Master Clutch cylinder. I know nothing about engines, but just wondered whether to continue to drive it. Current status is that getting forward gears is stiff and to get reverse I have to turn off the engine. Am I causing long term damage (synchros etc) if I use it before I change the Master cylinder ?
     
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  3. chrismorse

    chrismorse Formula 3

    Feb 16, 2004
    2,149
    way north california
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    chris morse
    HI Andrew,

    It sounds like the clutch is not being fully disengaged. This will definitely put premature ware and tear on the trans, not tagic, but not good either.

    Has the fluid been topped up and the system bled. This may cure it. If not, do you see evidence of leaking at the master or at the slave? Sometimes, the problem is the flex hose going from the chasis to the slave.

    hth,
    chris
     
  4. 350HPMondial

    350HPMondial F1 Rookie

    Feb 1, 2002
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    Edwardo
    #3 350HPMondial, May 16, 2009
    Last edited by a moderator: Sep 7, 2017
  5. CliffBeer

    CliffBeer Formula 3

    Apr 3, 2005
    2,192
    Seattle, Washington
    Full Name:
    Cliff
    Andrew, it's a clutch master cylinder, not a master clutch cylinder. It's called a master cylinder because it actuates the slave cylinder (downstream) which engages and disengages the clutch. You'll know you need a new master cylinder because either a) you have clutch fluid leaking from it, or b) you have a soft pedal even after properly bleeding the line.

    In any case, if you can't get into some gears and have to actually turn off the engine then you've got a sufficiently serious mechanical condition that driving the car in that condition is kind of goofy. I'm guessing you need a mechanic to fix this for you rather than DIY.
     
  6. 335s

    335s Formula Junior

    Jan 17, 2007
    869
    SF Bay Area
    Full Name:
    T. Monma
    In general, you would/should always repair/replace tandem hydraulic circuits in pairs....one would not change only one heel on a pair of boots-no?

    Generally speaking, these units are made in the UK, and re-labeled and the price is tripled to quadrupled, then taxed at the revised pricing!

    Since this is a clutch, and NOT the brakes, you ought to feel safe in having a quality machinist use a hone(Sunnen Mandrel Hones-NOT those dingle berry things sold by the local auto parts store...this is a PRECISION operation!!!) the housing bores and then replace the seakles using viton seals.
    It is suggested that you then use a DOT 4+(such as the Teves brake{ATE} oil made FOR MB-as opposed to "just the Teves oil"-there is a wet and dry difgference in BP-but more importantly the hydroscopic propertuies....

    Flush annually-AFTER wet season is over with...ANNUALLY....
    good luck!
     
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  8. CliffBeer

    CliffBeer Formula 3

    Apr 3, 2005
    2,192
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    Cliff
    #6 CliffBeer, May 17, 2009
    Last edited: May 17, 2009
    Ah, interesting. I've never heard the suggestion to replace a slave and a master together when one has failed. Seems like unnecessary overkill to me. The slave and master will, after all, be on different wear cycles depending upon relative heat, exposure to elements, etc.

    A surface hone is helpful only when there is no pitting of the bore surface. If there is pitting (generally in the bottom of the bore) then either it's a new cylinder or installation of a sleeve after a precision bore. I've installed both stainless and brass sleeves in slave/master cylinders and both seem to work well. My lathe and my mill are both good quality and precise.
     
  9. 335s

    335s Formula Junior

    Jan 17, 2007
    869
    SF Bay Area
    Full Name:
    T. Monma
    the fluid!
    The hydroscopic properties of the fluid are such that locale-per se-are not that significant.
    The totality of the environment-in this case, the interior fluid circuit of the hydraulic chambers, connectors, and lines-are ALL subject to the corrosive effects of and by the by-products of the chemical redux....more info than really required here...

    Since these are alloy housings, hydroscopic fluid(which likely went YEARS without being changed), and the resultant water, and ANY ferrous parts captive within the sol...means a galvanic/corrosive reaaction...."the pitting"...

    I personally avoid sleeving-perhaps your skill level is such that the usual pratfalls are not an issue.
    In my experience(which is more than you might think...), usually, sleeving is performed by inferior skilled practitioners with substandard tooling and equipment...
    I suspect, Mr Beers, this is not the case with respect to you...
    Merely, most times, after having to clean up after a prior fix of this nature, it is really cleaning up shoddy execution...

    Remember, these are Bendix hydraulic fixtures, if 1 is repaired, the strain then applied to the "other half" is usually enough to prompt a near immediate failure of the other component.
    Not ALWAYS, but frequently enough, to suggest that doing them in pairs is the more prudent approach.
    in the final analysis, what you and I nthink is the "correct" way is ALWAYS trumped by what is in the best interests of the customer-right?
     
  10. CliffBeer

    CliffBeer Formula 3

    Apr 3, 2005
    2,192
    Seattle, Washington
    Full Name:
    Cliff
    Hi 355, you make some good points obviously.

    I seem to have good luck with sleeving - I certainly take my time and have good tooling. I tend to prefer to sleeve with brass but stainless works fine too and I haven't seen any significant galvanic response over time that creates an issue.

    Typically, the master and slave cylinders are just plain mild steel, not aluminum or some other alloy mix, in my experience. Basic high speed steel or carbon tooling works well on this mild steel and a good fit and finish is obtained. Of course, with mild steel the pitting tends to occur in the bottom/lower portion of the cylinder where the h2o accumulates when not flushed regularly.
     
  11. fastradio

    fastradio F1 Rookie
    Professional Ferrari Technician BANNED

    Apr 26, 2006
    3,652
    New England
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    David Feinberg
    This has been a common repair practice amongest good repir shops, for many years...for exactly the reason you state. In those rare instances when the customer insisted that only the master was to be changed, the clutch slave cylinder frequently failed shortly thereafter...

    This is solid advice, if one wishes to have a happy customer...and not have the dreaded "Come-back" on the end of a tow truck!
     
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  13. CliffBeer

    CliffBeer Formula 3

    Apr 3, 2005
    2,192
    Seattle, Washington
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    Cliff
    #10 CliffBeer, May 20, 2009
    Last edited: May 20, 2009
    I still don't get it - the slave and the master are connected by a small diameter pipe with hydraulic fluid moving back and forth between them in small increments. How can the master cylinder directly impact the longevity of the slave? Obviously, if the master is allowing dirt to enter the line somehow, or corroding internally and introducing particulate matter then that can have a negative effect upon the slave (so flush the system as regular preventative maintenance). Is that it or does somebody have a different logic which is technically sound?

    I just don't buy the general statement that "its prudent to r&r the whole system" - come on, let's not waste our time and money replacing things that still have lots of service life left in them. If you're not a DIYer and you're happy writing lots of checks to ferrari mechanics to do these potentially unnecessary procedures then go right ahead I suppose. If you're doing the work yourself and/or don't want your life savings invested in your ferrari then being a little more discriminating between a) necessary repairs, b) good preventive maintenance, and c) unnecessary r&r seems wise to me.
     
  14. gidge348

    gidge348 Formula Junior

    Dec 12, 2008
    343
    Perth West Australia
    Full Name:
    Ian Wood
    Just my 2c worth, I have seen a similar problem with brakes in a friend’s workshop.

    A customer bought in a car for new pads, pistons were pushed back and pads changed a couple of pumps on the brakes and off he went. Came back 2 days later cursing and blinding that he had stuffed the master cylinder as it was now leaking.

    What had happened was that the fluid had not been changed in years and the bottom of the cylinder was corroded. Because the brake cylinder was working over a limited travel, where the piston normally ran was fine. When the brakes were pumped to bring the pads back the piston went past its normal operating area into the corrosion and cut up the seals. The customer did not want to hear this and in the end my friend replaced the cylinder.
     
  15. fastradio

    fastradio F1 Rookie
    Professional Ferrari Technician BANNED

    Apr 26, 2006
    3,652
    New England
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    Post #7 gives you the technical reasons why this is a good practice...
    Post #9 gives you the experience of over 25 years of working on a multitude of foreign cars...

    I agree that there's no reason to spend money friviously. Then again, ignoring both the technical resons and years of experience will likely lead to a clutch slave failure that could have been avoided...

    Naturally, YMMV...

    David
     
  16. Wade

    Wade Three Time F1 World Champ
    Rossa Subscribed Owner

    Mar 31, 2006
    32,194
    East Central, FL
    Full Name:
    Wade O.
    Precisely. The contaminants that caused one component to fail are still contained in the other. If you flush the lines then, well, you have clean lines. That's it.

    Chances are, if the vehicle had its clutch/slave system flushed on a regular basis then leaks/rebuilds/replacements wouldn't be an issue.

    I know of one other sports car (also mid-engine) that it is well known, within its community, to replace both cylinders at the same time. Otherwise, “fix” one and you'll be replacing the other soon thereafter; and thus the vicious cycle begins.
     
  17. ckracing

    ckracing Formula Junior

    May 20, 2006
    728
    Jacksonville,Florida
    Full Name:
    Charles
    Are you certain it IS NOT the clutch slave cylinder. The point of replacing both sounds like a good idea. You will save labor on bleeding the system once. My Mondial's slave cylinder starting leaking and I was able to drive the car by keeping the clutch master cylinder full of brake fluid. It took a week or so to get a replacement. I paid about $165.00 for mine.
    Good luck
     
  18. chrismorse

    chrismorse Formula 3

    Feb 16, 2004
    2,149
    way north california
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    chris morse
    I hope a few more Techs will give input.

    I was a service manager/service writer for 10 years, sold parts and service for sears and auto xed p cars for 20 years and have seen a lot of hydraulic "issues", so i can summarize my experience as- follows:

    If you don't bleed the hydraulics regularly, (brakes more often because of the higher temperatures/stress), then you are going to see more TOTAL system corosion/wear/leakage.

    One of the major issues is that when you replace or service stuff, "bleeding" the hydraulics - brakes or clutch - you are pushing the piston and seal further in the bore than they usually go, during the normal hydralulic function, to move the fluid and get the old stuff/air out. This is the major reason for the frequent master failure after replacing the calipers, rear wheel cylinders or clutch slave. If you ignore service and bleed, once in a milenium, you are going to have a lot of water/rust/filth - dead slave/caliper/wheel cylinders & masters.

    This leads to the shop policy/ conventional wisdom, of doing both.

    Most stuff can be rebuilt, honed or even sleeved.

    Sometimes it is cheaper to rebuild than install new, probably so with high end stuff.

    Doing it yourself is (almost always) cheaper.

    Price the parts from several sources. Check with your shop/tec to see if they have a problem with them using your parts. Rember, they are in business, part of their income is charging for the handling of parts and the warranty that they provide. Sometimes this is a little and sometimes this is a lot, you need to know if this is worth while for you and/or the shop.

    As i get older, i am more inclined to do more sevice myself, be more involved. I find a lot of enjoyment out of trying to do it right, spending time researching the mechanics, prior efforts of others and just doing it.

    hth,
    chris

    ps, tracking the car is the absolute best.
     
  19. CliffBeer

    CliffBeer Formula 3

    Apr 3, 2005
    2,192
    Seattle, Washington
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    Cliff
    Agree wholeheartedly with that - no doubt, when the master is bled using the pump the pedal approach that frequently destroys the seals. What I'm wondering about however is something quite different, specifically, how would a failed master or slave cylinder cause the other cylinder (master or slave) to fail?
     
  20. CliffBeer

    CliffBeer Formula 3

    Apr 3, 2005
    2,192
    Seattle, Washington
    Full Name:
    Cliff
    Yes, obviously. The suggest above was something quite different however, specifically, that you should automatically change the master or slave when the other fails. Rather, one should flush the system with some frequency. If that's done then there's absolutely no connection between the wear cycles of either master or slave (other than just age in general)
     
  21. CliffBeer

    CliffBeer Formula 3

    Apr 3, 2005
    2,192
    Seattle, Washington
    Full Name:
    Cliff
    David,

    Post #7 ain't too smart - that gentleman suggested that master cylinders and slave cylinders are alloy. Their not, they're mild steel. To make such a simple blunder suggests a basic lack of technical understanding. Words such as "sol" and "redux" are similarly non-technical terms and fairly meaningless. So, no, post #7 is not a technically sound response.

    Re: post #9, I have more year than that under my belt "working on a multitude of foreign cars" so I'll stick with my own conclusions thanks.

    Best regards,

    Cliff
     
  22. CliffBeer

    CliffBeer Formula 3

    Apr 3, 2005
    2,192
    Seattle, Washington
    Full Name:
    Cliff
    That makes total sense Chris - agreed. You're right, the notion of replacing both cylinders when one fails seems to stem from the fact that the master often springs a leak after the slave fails and the master is bled using the pump-the-pedal approach (due to running further down an often corroded bore).

    The point I'm making here is rather precise and subtle ie. the master does not necessarily have to be replaced when a slave fails if the fluid is changed with some regularity/attention and care is taken in bleeding the system (pressure bleeders are becoming more common to use by the DIYer).
     

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