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  1. Join Date
    Oct 2009
    Posts
    179
    #1
    Help mga sir, defective na ba ang hydrovac kapag nakapress ako sa brake when starting then hirap siya start. Pero kapag hindi naman nakapress sa brake ok naman siya. Paano madiagnose kung hydrovac nga ang problem? Papalitan ko na sana kaya lang baka sa ibang part my problem. Thanks.

  2. Join Date
    Feb 2009
    Posts
    5,130
    #2
    to eliminate a lot of guess work, you can check for engine vacuum at a non-ported vacuum source (e.g. pcv valve hose at the valve end) at idle speed and step on the brake pedal with the engine still at idle speed. if the vacuum level dropped with the brake pedal depressed, the control valve on the brake booster may be leaking atmospheric pressure into the vacuum chamber (front of the diaphragm) and causing a considerable leak. or check the system voltage with the engine running if the battery voltage drops with the brake lights on

  3. Join Date
    Oct 2009
    Posts
    179
    #3
    Quote Originally Posted by jick.cejoco View Post
    to eliminate a lot of guess work, you can check for engine vacuum at a non-ported vacuum source (e.g. pcv valve hose at the valve end) at idle speed and step on the brake pedal with the engine still at idle speed. if the vacuum level dropped with the brake pedal depressed, the control valve on the brake booster may be leaking atmospheric pressure into the vacuum chamber (front of the diaphragm) and causing a considerable leak. or check the system voltage with the engine running if the battery voltage drops with the brake lights on
    thanks sir, iccheck ko po.

  4. Join Date
    Mar 2008
    Posts
    52,517
    #4
    1. remove the hydrovac hose and plug it. then start. (an assistant willing to dirty his hand and thumb would be fine.) if engine starts ok, then it's probably a leaking hydrovac.
    2. weak battery of dirty battery contacts.. brake lights steal some juice away from the hi tension.. clean the battery contacts and/or piggyback a good battery and see. (removing the brakelights would have been better, but it might be hassle in some models..)
    Last edited by dr. d; October 25th, 2014 at 07:51 PM.

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Hydrovac