Leaky Brake Booster?! - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

SilviaSR20DET · 09-22-2014, 10:51 AM

Alright first off my s14 had issues with idle at times with a ka24de in it and especially with defroster on or a/c the rpm would dip pretty low when depressing clutch in to neutral. Now that i changed to an SR20det the same thing happens at times when depressing clutch into neutral. Is there a chance that my brake booster is leaking? It is sorta spongy at times and i do notice my rpm fluctuates when letting go of the brake pedal and my AFR's readings on my wideband change too when i do that. Thats the only thing i can think of that i have not changed since i bought the car and the brake has always been pretty sloppy.

Ktt88 · 09-22-2014, 10:52 AM

Quote:

Originally Posted by SilviaSR20DET

Alright first off my s14 had issues with idle at times with a ka24de in it and especially with defroster on or a/c the rpm would dip pretty low when depressing clutch in to neutral. Now that i changed to an SR20det the same thing happens at times when depressing clutch into neutral. Is there a chance that my brake booster is leaking? It is sorta spongy at times and i do notice my rpm fluctuates when letting go of the brake pedal and my AFR's readings on my wideband change too when i do that. Thats the only thing i can think of that i have not changed since i bought the car and the brake has always been pretty sloppy.

Correct me if im incorrect, but the clutch pedal and brake master cylinder are 2 totally different systems.

SilviaSR20DET · 09-22-2014, 12:30 PM

sorry about that should be more clear. Pretty much to sum it up every time i get into neutral after being in gear sometimes the rpm will drop significantly. When pressing on the brakes the rpms fluctuate as well so base on those things there could be a leak in vacuum thats causing the big dip in rpm which was occuring with my stock ka motor and now with the sr20det. So i suspected that there could be a leak at the brake booster... and was wondering if anyone else has a similar problem. I also noticed that in my Nistune ecu the neutral position switch doesn't work based on what i am seeing so im not sure if that has to do with it as well.

Ktt88 · 09-22-2014, 12:32 PM

With the engine cold, start it up and with it idling. Spray carb cleaner around the brake booster. If its leaking youll notice a change in rpm

09-22-2014, 10:51 AM	#1
SilviaSR20DET Zilvia FREAK! Join Date: Mar 2002 Location: Seattle, WA Posts: 1,221 Trader Rating: (9) Feedback Score: 9 reviews	Leaky Brake Booster?! Alright first off my s14 had issues with idle at times with a ka24de in it and especially with defroster on or a/c the rpm would dip pretty low when depressing clutch in to neutral. Now that i changed to an SR20det the same thing happens at times when depressing clutch into neutral. Is there a chance that my brake booster is leaking? It is sorta spongy at times and i do notice my rpm fluctuates when letting go of the brake pedal and my AFR's readings on my wideband change too when i do that. Thats the only thing i can think of that i have not changed since i bought the car and the brake has always been pretty sloppy.

09-22-2014, 12:30 PM	#3
SilviaSR20DET Zilvia FREAK! Join Date: Mar 2002 Location: Seattle, WA Posts: 1,221 Trader Rating: (9) Feedback Score: 9 reviews	sorry about that should be more clear. Pretty much to sum it up every time i get into neutral after being in gear sometimes the rpm will drop significantly. When pressing on the brakes the rpms fluctuate as well so base on those things there could be a leak in vacuum thats causing the big dip in rpm which was occuring with my stock ka motor and now with the sr20det. So i suspected that there could be a leak at the brake booster... and was wondering if anyone else has a similar problem. I also noticed that in my Nistune ecu the neutral position switch doesn't work based on what i am seeing so im not sure if that has to do with it as well.

09-22-2014, 12:32 PM	#4
Ktt88 Leaky Injector Join Date: May 2014 Location: Toronto, Canada Posts: 66 Trader Rating: (0) Feedback Score: 0 reviews	With the engine cold, start it up and with it idling. Spray carb cleaner around the brake booster. If its leaking youll notice a change in rpm