Low speed braking - Page 2

Secretasiansam · #1 10-07-2023, 07:12 PM

Quote:

Originally Posted by andrewwynn

When do you hear the whoosh? Vac pump pulls air Ina lot of places. I have an internal vacuum leak in my valve cover causing fits.

Sorry, resurrecting the thread. After idling the car to build booster pressure and stopping engine I can hear a whoosh inside the cabin and outside by the booster. I can not feel a rush of air anywhere.

EODguy · #2 10-07-2023, 10:20 PM

Quote:

Originally Posted by Secretasiansam

Sorry, resurrecting the thread. After idling the car to build booster pressure and stopping engine I can hear a whoosh inside the cabin and outside by the booster. I can not feel a rush of air anywhere.

What engine do you have?

My 4.8is had my vacuum pump fail and it sounded like gurgling water behind the dash.

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Secretasiansam · #3 10-07-2023, 11:25 PM

Quote:

Originally Posted by EODguy

What engine do you have?

My 4.8is had my vacuum pump fail and it sounded like gurgling water behind the dash.

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4.4 n62. No gurgling. Just one big whoosh with pressure built. I've pulled vac l8ne and it had vac.

andrewwynn · #4 10-08-2023, 12:14 AM

Quote:

Originally Posted by Secretasiansam

Sorry, resurrecting the thread. After idling the car to build booster pressure and stopping engine I can hear a whoosh inside the cabin and outside by the booster. I can not feel a rush of air anywhere.

Does brake pedal go firm after the whoosh? If so the woosh is the booster.

Either the check valve or the diaphragm

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Mistermorgan · #5 07-16-2023, 07:38 PM

I would guess so. I’m waiting for a new booster to arrive. There is very little that can go wrong with the vac pump itself outside of the o rings. The cheapest place to start would be the rubber hoses at each end of the vacuum hose, mine were definitely perished but I’d just be guessing at anything else.

I would suggest following Andrew’s instructions above

Secretasiansam · #6 07-16-2023, 10:37 PM

Thanks. Maybe important to mention. Symptoms occurred after changing brake light bulbs. I uses a short 2x4 to depress the brake pedal while I checked bulbs. Did I blow a hole in the booster by pressing too hard with the car off?

X5chemist · #7 07-17-2023, 06:54 AM

whooshes sounds = bad brake booster
I did one not too long ago on a different vehicle. Hopefully it's not too hard on a X.

andrewwynn · #8 07-17-2023, 07:57 AM

You said "hard on". Bwahhaahhaa

EODguy · #9 07-17-2023, 08:13 AM

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Mistermorgan · #10 07-29-2023, 02:29 AM

I’ve replaced the booster, I didn’t swap the master cylinder (I actually bought one but got sent one for. LHD which was no good for me)

I’ve run through the bleeding procedure using my foxwell and I’ve gone from having a hard pedal to a completely soft pedal. Guessing the master cylinder needs to be replaced too

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