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400i Brake Booster not functioning after complete overhaul from F400 Club member

Discussion in '365 GT4 2+2/400/412' started by rovexienus, Jan 13, 2019.

  1. rovexienus

    rovexienus Formula Junior
    Silver Subscribed

    Jun 10, 2010
    469
    Sainte Colombe, France (near Lyon)
    Full Name:
    Jean-Michel Savary
    I am posting this message on behalf of a F400 Club member. His 400i series 2 has a problem of brake system after a complete brake system overhaul has been performed.

    Is the suspect assembly (part n° 110792) shared with other Ferrari's of a similar period?

    Thanks in advance


    QUOTE
    I had my mechanic undertake a complete overhaul of the brakes, revision of callipers, change of hoses, and check valves.


    He also dismantled and changed the sealing gaskets and rings on the brake booster and on the pressure control valve (101415).


    With everything back in place the braking assistance is inefficient, at low revs it is zero and the red light stays on when the ignition is on (fluid level OK, handbrake off and pressure difference OK)!


    I am thinking if I read the repair manual correctly, that he should not have disassembled the Brake booster because it is factory set with the master vac.


    I have not been able to find the whole assembly (110792) on internet.


    If anyone has faced this problem and can give me some hints, I would be grateful.


    I believe there must be a solution to tune the brake booster, assuming this part on my car is not broken (it was not before the overhaul).

    UNQUOTE

    Original message in French

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  2. Bill26

    Bill26 Karting
    Owner

    Jun 19, 2005
    192
    Australia
    Full Name:
    Bill Murdoch
    It would be surprising if the problem is they booster itself as they are a very simple device (but a little tricky to take apart). In any case;

    For LHD, there is a different part number shown for 400 auto and manual - The 400 manual is the same part number as 365GT4 2+2 (124518) but with different plastic reservoirs. The auto shows part number 110792.

    For RHD, there are different part numbers shown - these have a different orientation for the vacuum hose fitting to put the hose high and on the outside. The two 365 and one 400A RHD's I have owned (plus all others I have seen) have had the LHD variant mounted inverted (so the fitting is low on the outside) from new.

    I have recently had a 365GT4 (124518) and 400A (110792) boosters and master cylinders apart for resleeving and replating and they are identical.

    The master cylinders for all are 1 inch diameter (not 25mm).

    Hope this helps.

    WM
     
  3. rovexienus

    rovexienus Formula Junior
    Silver Subscribed

    Jun 10, 2010
    469
    Sainte Colombe, France (near Lyon)
    Full Name:
    Jean-Michel Savary

    Thanks Bill,

    The owner of the car in question is located in New Caledonia, so not too far from you (in relative terms of course). His F'Chat username is CARUSO and I am involved as an intermediary because he is concerned about Google Translate ability to exchange back and forth technical communication.

    I have two questions from your answer:

    1-what is the service you have used for reserving and replacing (and can it be contacted from outside Australia)?

    2-if the source of the problem is not the booster itself, where else should the owner be looking?


    Thanks in advance
     
  4. Bill26

    Bill26 Karting
    Owner

    Jun 19, 2005
    192
    Australia
    Full Name:
    Bill Murdoch
    Jean-Michel,

    It is only 2.5 hours by air to Noumea from here - a very nice place that I am looking forward to going back to for sailing.

    If the brake pedal is hard with little pedal travel (and with the engine not running), it is likely that the hydraulic circuit is o.k. and the problem would seem to be the vacuum circuit/booster.
    Check that there is vacuum at the boost by taking off the fitting on the booster. Sometimes old vacuum hose can collapse internally and block the hose.
    If there is vacuum at the booster, then it is possible the booster is damaged. The major moving part is the rubber diaphragm which is not available as a spare part (as far as I know) but both of the diaphragms I have seen have been in excellent condition and normally would not need replacing. Damage during repair is possible. There is also a shaft seal that is available from Superformance (and probably other suppliers).
    Regarding the master cylinder itself, a seal kit is available from Superformance and there are many shops that do resleeving with a stainless steel sleeve (although maybe not in New Caledonia). Cost for sleeving here is about USD90 plus assembly if required.
    It would be possible to have the master cylinder serviced in Australia, but import and export regulations in both countries, might make it tricky.
    Regards
    WM
     
  5. rovexienus

    rovexienus Formula Junior
    Silver Subscribed

    Jun 10, 2010
    469
    Sainte Colombe, France (near Lyon)
    Full Name:
    Jean-Michel Savary
    Hi Bill,

    Many thanks for that, I will relay to the owner.
     
  6. raemin

    raemin Formula Junior

    Jan 16, 2007
    377
    Lyon (FR)
    Full Name:
    R. Emin
    As for the export/import duties, I do not remember the exact custom rules for this -still- French overseas territory but should not be worse than for the metropolitan area. There is a specific procedure for repair services, in order to be charged only for the repair and not for the full cost of the part as it crosses borders. It normally involves directly getting in touch with customs at your local airport, filling the proper paperwork and then request your seller to send directly the part back to airport custom (not your door!). Most local carrier (eg: GLS) are not familiar with the procedure so they never apply the proper tariff, hence the need to liaise with the custom desk.

    "livrer en douane" is the magic formula in order to pay the fair custom tariff. That's how my SwitchPitch TH400 used to travel across the Atlantic...

    Not sure how the process has evolved recently, but this owner should liaise with custom in any case: owning a 400i in New Caledonia is quite a challenge so he'd better be good at sending (and getting back) parts across the world!
     
  7. rovexienus

    rovexienus Formula Junior
    Silver Subscribed

    Jun 10, 2010
    469
    Sainte Colombe, France (near Lyon)
    Full Name:
    Jean-Michel Savary
    Hi Bill,

    The owner is happily surprised that your very useful answer came so quickly and from so close to him. He will carry out the tests you have suggested. I am sending you a PM.
     
  8. CARUSO

    CARUSO Rookie

    Feb 2, 2018
    10
    Hi Jean Michel & Bill

    Thank you very much for your help, in a first time I will order the signal valve pressure difference to change it, but I'm afraid it's the faulty booster

    I will keep you informed of the progress of the repairs.
     

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