Hydraulic pump weak?

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René Hazejager
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Registriert: 10.05.2005, 13:31
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Hydraulic pump weak?

Ungelesener Beitrag von René Hazejager »

Hi,

Question specific for Roland Müller:

I can screw up my hydraulic system when I start the engine and pump up/down the brake pedal: it vibrates during 5-15 secs and within 1 minute I get the acoustic warning: brake system error! (=not enough hydraulic pressure, I think).

When I switch off the engine I do lose pressure after 40x pumping the brake pedal->hydraulic bomb should be OK. Do you have the same problem?

Next week I will check my hydraulic system. Any suggestion is appreciated (by anyone).

See picture.


Thanks!
René.
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Porsche 911S 1972
S6Plus 1996
Sebastian
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Registriert: 19.09.2004, 23:51

Ungelesener Beitrag von Sebastian »

I think, thats your HBZ (Hauptbremszylinder...i don't know the translation of this word)...i have the same problems :?
Thomas Brem
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Registriert: 30.11.2004, 16:26
Wohnort: St. Gallen

Ungelesener Beitrag von Thomas Brem »

Dear René

Thank you very much for your good hints in the German Forum. I am sure that we have the same problem, but yours seems to be more advanced.

It is the same light, including the accoustic warning. But the vibrations occur only when I pedal the brake the first time after starting (that means for one second, and only in the morning, when the car was standing overnight). When I pump the brake before starting the engine in the morning, the pedal is stiff. Does this mean that the pump is empty? I will also try to provoke it by pumping the brake 40 times.

Did your research lead to a final diagnostics?

Regards, Thomas
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René Hazejager
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Registriert: 10.05.2005, 13:31
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Ungelesener Beitrag von René Hazejager »

Thomas,

I will fix an appointment this week. We will measure the pressure in the hydraulic circuit (80-100 bar!), specifically directly after starting the engine. We will losen the pressure switch on the brakeservo and connect a gauge. This switch detects low pressure, and thats why you get the warning. I do not understand the vibrations in the pedal, you and I experiencing 5 secs orso. But soon I will know...

Your brake pedal feels hard when the pressure in the system is low (no brake servo, keine Bremsverstaerkung). This is always the case after 3-6 hrs stand still. But check your bomb (accumulator) by running your engine a few minutes (or after a ride), switch it off and you must be able to brake 30x minimum before you lose pressure->hard pedal. Please check also your hydraulic fluid level.

It is the same as the expansion drum (expansions Trommel beim Heizung) for your central heating system: the water presses away the membrane in the red drum, which is under pressure by nitrogen. So it prevents your radiators at home from exploding when the water expands....Physics from school, remember still?

Take care!
René
Porsche 911S 1972
S6Plus 1996
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René Hazejager
Ex-Owner
Beiträge: 50
Registriert: 10.05.2005, 13:31
Wohnort: Aalsmeer

Ungelesener Beitrag von René Hazejager »

Hi all,

See post http://s6plusforum.typ-c4.de/viewtopic.php?t=420
for the results.

Marc, you can close this thread, my hydraulic pump is OK!


Thank you.
René.
Porsche 911S 1972
S6Plus 1996
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