Bertrand Daoust

Hi,
Can anybody tell me what is the metal part beside the plastic reservoir with the inscription WARNING in red in this pic please.
Just noticed it is leaking.

davek9

Not sure but it could be a "High Pressure" reserve, it is all part of the PSD pump, the warning is for "High Pressure" break fluid, that is what is used in the system.
If you do a search on PSD, there area few writes up on how it all works.

9x8

You don't really have to replace it - it can be welded.
Here's a pic

Bertrand Daoust

Thanks guys.
Is it the filter casing.

9x8

No, it's not?
It's indeed a high pressure reservoir (pressure accumulator) - and if it's leaking you should really get it fixed or replaced.

davek9

There is also a small filter in the bottom of the plastic one.

the flyin' scotsman

Bertrand........you should know that to properly bleed the PSD system you need a special tool to plug into the diagnostic port and run the PSD pump remotely.

Not sure who has one in Eastern Canada......... you need the Porsche hammer or JDS spanner or Theos Diag System.

Randy V

Actually, any 12v source will do.

Here's the best write-up out there:

http://928oc.org/journal/psd1.pdf

the flyin' scotsman

Agreed Randy there's more than one way to skin this cat but the correct tool does make the procedure easier.

Ninespub

Yep, that's the pressure accumulator alright. I had all my fluids changed about 7 years ago and a month later as I was parking the car it exploded. Don't know why, but they were virtual unobtainium back then (about $1000 new) with no used ones available. They disconnected the PSD and put a bolt somewhere in the rear end which gives me either an open differential??? or a fixed??? (I really don't know.) I found another complete used PSD system a couple years ago and have not gotten around to installing/testing to see if its any good but I'll get a "roundtuit" this year. I guess though, really, that I have not missed the PSD enough to know the difference with or without it today.

Vilhuer

One interesting observation about PSD. It seems that if driveshaft joints are just exactly right kind of worn, not totally failing yet but badly worn, PSD computer will go mad and apply full 100% lock on tight turns no matter how slowly car is driven. This causes car to behave very oddly, almost like offroad vehicle.

docmirror

Hmmm, that sounds strange since the PSD uses the ABS sensors out at the wheel hub. I think there is no relation to engine speed, or rotation of any of the driveline components involved. It also takes up sense info for lateral accel from the motion sensors under the drivers seat. I can't see how wear in the drive line including the shafts would have any effect.

The only thing I can see happening is that the PSD is being applied to affect change in the wheel spin, and if the change isn't observed from the sensors, the PSD goes into a higher pressure mode. I guess that could be it.

Vilhuer

Its probably some kind of oscillation which keeps on feeding itseft until 100% lock is achieved, which will happen very quickly. Probably requires very specific conditions. Problem went away totally right after shafts were changed. Old shaft had been apart during winter and ABS teeth were clean in old shafts so it wasn't caused by them. Joints were just too worn out. Everything was and is in ok condition in this particular ex automatic GTS which now has 5sp from '90 GT.

ROG100

Bleed the system and change the reservoir.
The accumulator is pretty high pressure.
Fluid looks dirty.

docmirror

Or, repl the reservoir/accumulator first, then fill and bleed.