Power Steering Fluid, ATF system with URS6 PAS Pump

[URquattroGus]

My 1984 WR quattro now has a AAN 20V engine fitted. The brake assist and Steering rack are unchanged. In it's orginal form I always ran in on ATF.


My question is quite simple, since I now have the URs4/s6 pump for packageing reasons, what is the best fluid to use?

I understand it is ok to use the later mineral fluid from later quattro's (MB/RR) if you flush out the system?

I believe an S6 used something different again?

Obviously my concern is that of ATF eating the S6 power steering pump seals, and also not working as well with the pump.

[Mikes2]

you can use the G00 4000 on early and late cars. It changed in 1985/6

You can't use ATF in later cars.

At the time of the change, the part number for the fluid remained the same G00 2000, although it changed a couple of years ago to the new number.

I'd use G00 4000

[URquattroGus]

So using this shouldnt hurt the sealing in the old rack and or brake acumalator??

Whats the best way to flush one of these systems?

[andy10v]

Does the WR system operate at the same pressure as the AAN?

[Mikes2]

The old rack will be fine. I'd consider a new style accumulator

System pressure is determined by the pump which is from the AAN. The ATF will break down at the pressures generated by the tandem pump

[popdemonic]

ATF won't hurt the PAS pump,Rack seals but it's gonna hurt the valve inside the brake servo and bomb.
The early A100 C4 (with vacuum brake booster)uses the same PAS pumo seal kits as urs6.I have seen many guys is running the ATF
On the steering assisted system without issue.I lost my servo and bomb from pouring the ATF by mechanic.
This's the saddest story.

[URquattroGus]

ATF won't hurt the PAS pump,Rack seals but it's gonna hurt the valve inside the brake servo and bomb.
The early A100 C4 (with vacuum brake booster)uses the same PAS pumo seal kits as urs6.I have seen many guys is running the ATF
On the steering assisted system without issue.I lost my servo and bomb from pouring the ATF by mechanic.
This's the saddest story.

Well its been good enough for the last 27 years Think you've got it the wrong way round here.