Hydraulic servo system.

[twoqu]

Has anyone got the official information about the hydraulic servo system?
In particular the following:
1. The operating pressure.
2. The gas pressure of a new accumulator.
3. Minimum pressure of an accumulator.
4. The pressure drop needed to trip the low pressure switch.

[4WheelDrifter]

1. 140 bar.
2. 78-82 bar @ 20ºC.
3. 30 bar @ 20ºC.
4. 127-87 bar.

Also worth noting is the delivery rate of 0.3 litres/min.

[twoqu]

Cheers Stu!
Next time there is a gathering I'll bring my gauge.

[S2central.net]

Thats a BIG guage... I recall seeing 140bar in the manual alright - hydraulics are nasty when they go bad near body parts...

[twoqu]

Well its the only thing that will tell you that you bomb is dead. I also wanted to disprove the "myth" that the more presses it take to get the brake pedal to go hard is the best measure of the health of the accumulator.
The accumulator only provides adequate reserve pressure for a few emergency stop/steering incidents if the engine dies. I think this 20 or so pushes is only stated to ensure that the hydraulic pressure is completly depressurised so that the sysyem can be opened without a green geyser!
Anyway without knowing the correct pressures and having a gauge its impossible to know whats going on.

[S2central.net]

Totally know where you are coming from... Though I can tell you the bomb doesn't provide any emergency assist for steering as I had first thought - see my two hairpin thread from earlier this week.

Where did you get a hydraulic pressure gauge from and what sort of money ?
I priced up the official VAG item with its fittings and such in the past but it was expensive - nearly 300 quid from memory.

[twoqu]

I have the correct VW1441. But dare say something else could be rigged up as long as it can handle those types of pressure. The only thing is getting a large enough dial to get accurate readngs.