Hydraulic to vacuum servo conversion

[A80Avant]

180gbp for my lhd rs2

[A80Avant]

are you talking about the same hose? cause the hose that goes from the pump to the bomb also has a nylon fitting.
I noticed that the hose from pump to rack, has a metal piece in the middle which seems about 1mm narrower than the rubber part. if that is the case, then the nylon bit may have an internal restriction as well? but how much?

when you reused the loop, was it made to have that 30deg angle between the rack and rubber hose as i mentioned above?

[S2central.net]

Why the 30 degree requirement ?

Very odd... hydraulics arent my thing obviously.

[tscheel]

are you talking about the same hose? cause the hose that goes from the pump to the bomb also has a nylon fitting.
I noticed that the hose from pump to rack, has a metal piece in the middle which seems about 1mm narrower than the rubber part. if that is the case, then the nylon bit may have an internal restriction as well? but how much?

when you reused the loop, was it made to have that 30deg angle between the rack and rubber hose as i mentioned above?

The hose from pump to rack. The metal piece is only for attaching the hose midways in the "wire hanger" like piece, the nylon/plastic restictor pulls right out, and has no indents or so - because theres also a metal piece on the inside of the rubber hose, on the outside of the nylon. Very over engineered, but that's why we love them B4's right?

I tried to mount the loop as it were, but I must check again. I wasn't aware of the woodoo involved in the assembly process

There's powerful forces at work, maybe pulses from the pump cause the noise/vibrations. I don't have noticeable vibrations in the steering wheel though. Maybe my loop help a little.

[A80Avant]

there is no explanation on the manual. but it says the mounting on the rack needs to be parallel and the rubber exit at 30d from the rack. loop can hang in between

[S2central.net]

Just had a look on the parts system.

NG motor has single vane pump - 034 145 159 L (Vickers) or 050 145 155 B (ZF)

LHD - 6A & ACE motors also call up single vane 050 145 155 B

But on a V6 (AAH or ABC) we have DUAL vane pump for RHD and single vane for LHD - there mustnt be enough room for vac servo in RHD.
Actually we see this on the 6A, ACE engines as well with a tandem pump for RHD... same part as S2/RS2.

RHD V6 tandem pump is same as S2/RS2 - 8G0 145 165

LHD V6 single vane pump - 050 145 155 C

Bracketry is common on V6 motor so they must both mount the same way.

[A80Avant]

thanks for that Paul,
the pdf was from the US so that is why they meant single vane on the V6.

so ill keep that part number to have handy if it required

[A80Avant]

a little update,

after driving the car again today, i noticed that the noise is higher/louder when starting from stationary, and gets louder on right hand turns. I suppose that has to do with the pressure build up on right hand turn, whereas the left hand, it is barely audible as the rack is fully extended(as being a LHD its the opposite from RHD).

When turning the wheel, i was trying to listen where the noise is coming from, and it seems that its the hose itself and the rack. The pump is absolutely silent!. I touched the hose while the wife was turning the wheels and you could feel the whole thing vibrating!!

[tscheel]

a little update,

after driving the car again today, i noticed that the noise is higher/louder when starting from stationary, and gets louder on right hand turns. I suppose that has to do with the pressure build up on right hand turn, whereas the left hand, it is barely audible as the rack is fully extended(as being a LHD its the opposite from RHD).

When turning the wheel, i was trying to listen where the noise is coming from, and it seems that its the hose itself and the rack. The pump is absolutely silent!. I touched the hose while the wife was turning the wheels and you could feel the whole thing vibrating!!

Oh! I just remembered - on my NG (the car I converted to 7A) hose originally theres a 2 piece lump of metal mounted on the hose - just at the exit of the loop. Vibration damper i presume - it must be around 200g or more. I dont have exactly 30 degrees on my 7A, more like 40 - I'll try to correct it and mount the lump to the hose if possible.

My S2 don't have the lump and is silent. It's closer to 30 degrees, but I haven't measured.

If it is all just amplified vibrations, It shoudn't be dangerous to the rack, right?

[A80Avant]

can you take a photo of the lump? and where can this be found?

[tscheel]

I'll grab a pic later.

[jade]

are you talking about the same hose? cause the hose that goes from the pump to the bomb also has a nylon fitting.
I noticed that the hose from pump to rack, has a metal piece in the middle which seems about 1mm narrower than the rubber part. if that is the case, then the nylon bit may have an internal restriction as well? but how much?

when you reused the loop, was it made to have that 30deg angle between the rack and rubber hose as i mentioned above?

I have replaced these hoses, I reused the ends and removed the restrictors and fitted them to the new hoses

Yes under the metal piece on that hose it has a metal restrictor inside the pipe not sure of the size

[A80Avant]

That is good news jade! Thanks for that!

[tscheel]

I have replaced these hoses, I reused the ends and removed the restrictors and fitted them to the new hoses

Yes under the metal piece on that hose it has a metal restrictor inside the pipe not sure of the size

When I got mine repaired, the metal piece midways was cut. It was :

(0 : Outer rubber tubing (like a bike inner tube))
1 : short piece of crimped metal (crimped to fit the hose holder on the motor mount)
2 : black hydraulic rubber hose
3 : short metal tube
4 : white Nylon/Plastic (4mm ID) tubing, which wasn't affected by the inner metal tube (3).

I think the inner metal tube just supports the outer metal so the crimp process doesn't destroy the nylon tubing.

Some form of restictor appears to be needed, maybe just the 4mm ID tubing. Damned hypersensitive system

[A80Avant]

This is why I could give the money Audi asks for some piece of mind...