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Brake Pedal

Adam 33

By Adam 33,
in Engines & Forced Induction

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Adam 33 Collaborator

Adam 33

Posted
Posted

Hi guys and gals

I was just wondering, when i start up my car and leave it ideling then pump the brake pedal a few times the revs go down and almost stalls.

It never stalls but it feels like it is just about to.

Is this normal or is there something wrong?

If something is wrong would anyone know what it is?

The whole car is still under warrenty, so i want to sort it out.

Thanx

Adam

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skylark Collaborator

skylark

Posted
Posted

I believe the brakes use manifold vacuum to operate the vacuum servo unit, this is the big round black thing behind your mastercylinder that helps you put pressure into it. Repeatedly pumping the brake pedal on a cold engine would be like pulling off a vacuum line and would stuff around with the engine management. RB engines that have an issue with "idle hunt" are usually first inspected for vacuum leaks. Do the revs drop when you pull the vehicle up to a stop while driving?

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skylark Collaborator

skylark

Posted
Posted

If the brakes feel ok and you don't have to stomp on them hard to pull up the vehicle then the vacuum servo unit may not be defective/leaking. I just went out, started my r32 and pumped the pedal 3 times and the rev's dropped significantly but then returned to normal. Is there a reason you are depressing the pedal in succesion? I don't think there is anything wrong with your vehicle adam but if in doubt consult a professional mechanic.

Hope this helped

Rhys

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SLY33 Mentor

SLY33

Posted
Posted

skylark, your on the money about the brake using vacuum thing.

Problem has to be vacuum related. It can be real hard to locate very small leaks in the system tho.

as lark said, is there a reason you pump the brake pedal?? Or you might just be fussy like me and think "i should be able to pump the brake pedal whenever i like, and not have any problems, this is a SKYLINE!!"

:P :P :D :D

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