John Veninger

No need for race fluid in the PSD.
Use the best low moisture absorbing Dot 3/4 you can find

Mrmerlin

I think that the best fluid is the one thats made for the car. I have seen more than a few time where other fluids have been added to top things up and the differing MFG properties of the fluids have caused problems with hydraulics .
So said another way ATE is the hydraulic supplier for the 928 as such it only makes sense to use ATE products as they are designed for the system specifics and thats what was originally installed in the car.
If you have super blue in your brakes then use it in your PSD, one fluid good for all 928s.

John Veninger

Porsche does not specify ATE fluid for the system, they state a specification.
The PSD system is usually completely flushed, not topped off.

ATE is a very good fluid, but does not have the moisture resistance of some other brake fluids on the market today and is more expensive.
The PSD system is more about hydraulics and keeping moisture out than high boiling points.

Brett Jenkins

Yeah, I found that when I was trying to pound out that dent. I was baffled at first as well. Hope the car is coming along nicely.

worf928

+1

Any recommendations for a good 'work-a-day' DOT 4 fluid with good moisture resistance? How about the Valvoline Synthetic DOT 4 (non-silicon based)? That seems to be about the only DOT4 at the stores here other than "Billy Bob's" DOT 3/4 compatible...

Rob Edwards

I had flushed last fall with Castrol GT-LMA, which says that it exceeds all DOT3 and DOT4 specifications. Given that this car is 95% street/5%AutoX driven, is that good enough for now? It's been 18 months since I bled the brakes, and I have some Typ 200 in the garage. I'll just bleed everything together soon.

Mrmerlin

I guess you can use whatever fluid meets the factory spec, but I still have an idea that if you use ATE fluids theres a whole lot less of a chance that seal damage will occur, I have an ATE master cylinder in my car .
I know the PSD gets flushed not topped up as no fluid is used or lost while its operating, the resivour sealing cap on the PSD sure looks like a cap MFG by ATE.
More than a few times i have found damaged hydraulic systems due to mixing different fluids, especially the syn fluids , though they may have less of a tendency to absorb water they seem to make the seals swell over time. Possibly due to having the seals first immersed in one fluid then another.
If the hydraulic system is serviced as it should be you will get good service from the ATE fluids
Thats my 2 cents, Stan

John Veninger

Think Rob just mentioned one

worf928

If could *find* Castrol-LMA I'd buy it. I guess I just need to look harder.

RyanPerrella

whatever brand auto parts store you checked, try the competitor. Its pretty common