Hydraulic to vacuum servo conversion

[robo]

YOu need to get a specific V6 hydraulic pump... some are single vane, some are dual vane. My 1992 V6Q has dual vane for PAS & Brake Servo - but there are some changes across the years with LHD vs RHD just to add confusion.

Its very weird about that special hose - no clue what is going on there.

I have lhd CQ and it has servo brake and power steering, looks very much like s2.

[Error404]

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

There is no restrictor. There is a metal crimp which allows the hose to be supported without crushing it. I have the parts in my garage at home i'll post some pics later.

[Error404]

I too have messed with my PAS pressure line and mine does make a whine when turning the wheel, it is not very loud but noticeable.
I am sure, the 30 degree angle means nothing other than making sure the hose is attached to the rack in an unstressed position.
I am also sure that the loop on the rack end means nothing as the very early 7As do not have this, the hose is fitted via a compression fitting to the side of the rotary pump on the rack.
I have a pressure bypass valve in my pressure line to adjust the steering assistance, I can turn the pressure right down, the noise does not alter. So it is not pressure related. The noise is heard as the steering is turned, but not when left still, therefore I am sure it is flow related as the pump supplies fluid on demand to the rack.

[A80Avant]

I'm having trouble understanding how it can be flow without being pressure related? If the noise is higher because of less flow then wouldn't the pressure be lower as well and vise versa?

[Error404]

As far as I understand it there is negligible flow when the steering is stationary. The pump pressure is controlled by an internal relief valve, so when flow demand is reduced at the rack pressure is relieved at the pump. Pressure remains pretty constant upstream of the rack, due to the relief valve. Flow alters in line with demand from the rack

[A80Avant]

i see,

the facts are though that 2 of us have the OEM hose changed with noise coming up, and when the OEM is used in any configuration the noise is less. I am not sure why 7A engine has no loop, but it may be that the designated pump has less bar pressure(some are 100, some 75) and that may have something to do with it.

I will have the hose changed and report back.

[tscheel]

As promised - pic's of the "damper" lump. I think I got a little les noise when I mounted it, but it can be a placebo effect.
Also you can see the fitting on the pump-to-bomb hose. There was a similar fitting on the pump-to-rack hose.

[A80Avant]

That is nice. The s2/rs2 apparently didn't need that but I wonder if fitting something like it would make a difference.

Does it have a part number?

[tscheel]

That is nice. The s2/rs2 apparently didn't need that but I wonder if fitting something like it would make a difference.

Does it have a part number?

Didn't see any - don't think so. I think I once checked Akte without luck. It looks VAG enough, though. It came off a '92 2,3E (NG)