348 - ABS Accumulator pump re-pressurize question | FerrariChat

348 ABS Accumulator pump re-pressurize question

Discussion in '348/355' started by Ferrarium, Jun 16, 2019.

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  1. Ferrarium

    Ferrarium F1 Veteran
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    Jul 28, 2018
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    Central NJ
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    Eric
    Brakes seem fine, no leaks all the parts clean with factory slip marks so the components are old. Planning winter work and will have brake fluid drained for various bit of preventative work. I checked the ABS accumulator function to see if its on the list of things to possibly replace, here is what I need to validate from other owners.

    When car is on accessory and I push the brake pedal, it takes 3 brake pedal pumps then the ABS pump runs to re-pressurize the accumulator, it runs for about 1.5 seconds. I understand if you press the brake pedal and it runs each brake pedal press the accumulator is clearly bad but I would "think" it would be more than 3? What is the normal within range Brake pedal strokes for the 348 accumulator to recharge from the ABS pump?

    Thanks!
     
  2. User-C3

    User-C3 Karting

    Aug 29, 2018
    204
    Detroit
    Full Name:
    Trevor
    I just installed a used jaguar xj6 pump and its 3 pedal pushes also and then the pump kicks on. I feel like most I have heard is 5 with a brand new accumulator.
     
  3. Ferrarium

    Ferrarium F1 Veteran
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    Eric
    Yep I read 5 also but it seems 3 is not unexpected so I'll replace accumulator another time perhaps.

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  4. Wade

    Wade Three Time F1 World Champ
    Owner

    Mar 31, 2006
    32,793
    East Central, FL
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    Wade O.
    Interesting about those steps.

    For mine, if the car's been sitting for awhile, I always turn the key to position II and don't touch the brake pedal until the ABS pump stops (today it took about 50 seconds). The ABS light goes out (turns off) just before the pump stopped.

    Then, stepping on the brake pedal, I turn the key to position III to start the car (gear in neutral of course). During this, the ABS light comes on briefly.

    But looking at the Owner's Manual, it says to go straight to position III to start the car. Old habits for me I guess, and did the same with my exes - 348ts and 88 Mondial 3.2 (mostly the same ABS system).


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  5. Wade

    Wade Three Time F1 World Champ
    Owner

    Mar 31, 2006
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    East Central, FL
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    Wade O.
    However, if I've been driving the car, turning the key to position II the ABS light goes out within a few seconds (no pedal pushing).
     
  6. Ferrarium

    Ferrarium F1 Veteran
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    Eric
    I always turn the key to position II and don't touch the brake pedal also. I let the relays energise and what not. The abs pump runs for few seconds if that. Maybe if it sits longer it will run longer. I'll discharge the accumulator and the. Turn key to II and see how long it takes to charge.

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  7. m.stojanovic

    m.stojanovic F1 Rookie
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    Dec 22, 2011
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    Miroljub Stojanovic
    On my 348, the ABS pump will run with the key in position I (acc). After 1/2 to 1 day sitting, it does not run at all (system still pressurised) but after a week, it runs for some 30-40 sec.

    I f the ABS pump runs for a fairly short period of time after full depressurisation, time to change the accumulator. I recently suddenly got a lot of air in the breaking system (could hear the air being "squished" every time I press the brakes). The diaphragm of my old accumulator had failed and released the nitrogen into the brake fluid.
     
  8. Wade

    Wade Three Time F1 World Champ
    Owner

    Mar 31, 2006
    32,793
    East Central, FL
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    Wade O.
    I'll check again. Maybe mine runs the pump from "position I" as well. But I always go straight to II pausing before going to III.
     
  9. Ferrarium

    Ferrarium F1 Veteran
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    Eric
    I pressed the brake many many times until the pedal went stiff with no travel. I believe that depressurizes it? I turned the key to II and the ABS pump ran for 50 or so seconds as I was counting. You could hear it working harder as pressure built towards the end of the cycle. Seems my usual few seconds of charging it because I drive it weekly when weather permits and it is holding a charge presumably.
     
  10. Qavion

    Qavion F1 World Champ
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    Feb 20, 2015
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    Ian Riddell
    For info:
    The ABS pump is powered by the battery/alternator, but control of that power depends on the accessory (I) and start (III) contacts of the ignition lock. Moving the key to start (III) disables the pump, but also sends a signal to a warning light test module to illuminate the ABS light (when cranking). When starting, the light is not indicating the health of the pump/system pressure.... only the bulb in the ABS warning annunciator.
     
  11. m.stojanovic

    m.stojanovic F1 Rookie
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    Dec 22, 2011
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    Miroljub Stojanovic
    Seems good. If I remember well, my ABS pump, while the engine is running, also comes on briefly after some 3 pumps to top-up the lost pressure. The pump goes off at some 2,600 psi and comes back on when the pressure drops to 2,000 psi.

    Comparison of the 348 pump pressure switch settings with the settings on the Jag and Alfa units (practically the same):

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  12. yelcab

    yelcab F1 World Champ
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    Nov 29, 2001
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    San Carlos, CA
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    Mitchell Le
    I know that play … much ado about nothing...
     

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