hi guys,just done a service on my car last night,started the car for a sec to get new oil round and as I stoped the engine I could hear a hissing sound coming fronm the brake master cylinder area,the hissing stops shortly after the car is switched off,is the cylinder gone?.

cheers in advance.

Sounds like the servo, check the pipe from it to the intake manifold for leaks.

Sent from my GT-N7100 using Tapatalk 2

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White 1990 GT Four ST185 (Import)
Now with 205 engine, ecu, engine & internal loom inc Speedo binacle and heater control.

il check that when i get home,cheers mate

Try the brake pedal after the hissing stops to see it it still has air in the servo.

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If at first you don't suck seed, try drier grain.

Could also be a leaky one way valve or a perished seal

I tried the brake with the engine running couldn't hear any noise, brake pedal felt ok only thing I noticed was the fluid raised slightly when I braked,couldent see any dodgy hoses,theres no fluid leaking anywhere inside the car or engine bay, the noise dose seem to be coming from bottom area of the cylinder/reservoir.

can it be refurbed with a kit?
will it pass my MOT sat like this?.

cheers guys

Switch off engine
Wait til hissing stops
Then try the brakes. A solid pedal first pump indicates a leak in the servo but it will always go hard after a few pumps

If it does lose pressure then more tests are required to find the fault

I did try the brakes after the hissing stopped pedal wasent rock hard,like you said it needs a few pumps to get really hard
is the rebuild kit on tcb the one that overhauls the whole unit?

The tcb unit is a master cylinder kit. Afaik the servo isn't rebuildable but if you're not experiencing any issues I wouldn't go making trouble anyway

Didn't Mike have his servo rebuilt?

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Don
GT4DC Chairman
1994 Toyota Celica GT-Four ST205WRC JDM 269bhp @ 0.9bar
1994 Toyota Celica GT-Four Special GT 590bhp @ 1.8bar
1989 Van Diemen RF88/89 Formula Ford 1600
2008 Nissan Patrol GU 3.0L ZD30DDTi 154bhp

Nope - there is no kit available, I rebuilt just the master cylinder.

A new servo from Toyota is fearsomely expensive, there wasn't anything wrong with mine so I left it alone.

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1996 ST205 UK

Could it be a vac leak around the inlet manifold area ?

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2004 Subaru WRX

well it passed MOT with only a bulb in the number plate gone lol.