Flush Power Steering fluid

[Paffel]

I think some numpty has put ATF in very recently on this S80 I've bought - the fluid is still thin but has turned a browny colour - I'm assuming they didn't look and see the green CHF in there!

Before it does any further damage (the only symptom I have at the minute is an occasional bit of wrestling with the wheel when steering at roundabouts), I'm looking for the best way to purge it.

Had ideas to drain the reservoir, then remove the return from the reservoir - blank off the reservoir hole, and lead the return hose to a bucket. Fill the reservoir with CHF, jack the car up, then operate steering to pull the new fluid through.


Any other ideas? I didn't want to expunge the reservoir and top up, rinse and repeat as I reckon I'll waste a load of fluid just to dilute the ATF in there enough to not cause bother.

[Paffel]

Ah - just found this, this was the technique I was thinking of...

http://www.matthewsvolvosite.com/for...pic.php?t=8644

[Brendan W]

That looks like a lot of fuss. I open the return hose at the reservoir an put it into a large mayonnaise jar beside the reservoir. Ask the better half to run the motor for a few seconds until the reservoir is nearly empty, top up the reservoir, empty the dump jar and repeat until the stuff coming back the return is bright green and then once or twice more for luck with a few steering inputs thrown in there somewhere to help scour out the corners. Having a second litre to hand is a good idea. Seals pay back handsome for nice fluid and a swept floor , so to speak. In the context of a new rack or pump a second or third litre of fluid is nothing.
You can never have too many rags.

[Paffel]

Good shout, engine on would make it easier I suppose.
Bought 2L of comma CHF today which should do the job - as you say, for the price of a new rack it puts the fluid cost into perspective!

[Brendan W]

While you're at it a magnet on a wire is great for fishing for metal in the bottom of the reservoir before you start. It's amazing the amount of stuff down there - surprised there wasn't a supermarket trolley. I reckon I got quarter of a sugar cube of mostly black stuff with a smattering of fine silver flecks no bigger than 0.3 mm - like I actually measured them really

[Coventry]

I've also got a Nd magnet dangled inside my PAS reservior. It picks up a fine coating of muck/particles which I periodically wipe off. Better than circulating around the rack...

[Paffel]

Well I've just been out and lifted the reservoir free from the car, but the hose is in an awkward place!

The feed hose on the left (fatter one) heads to the pump, and the return (nearest, right side) couldn't be positioned any worse if it tried!



I have taken off the return hose while holding the reservoir vertical, I couldn't see how I could get a receptacle of any sort next to it in this position! It looks like a 12mm connection if I were to put a pipe on it.

To be honest, that return pipe is extremely long, and disappears to the PS cooler - It might be easier for me to unclip the return hose at the res, blank off the res, and feed the return hose through the car to the floor, then pop a bucket down there to capture it.

Is your reservoir the same as mine Brendan? If so, how did you get a jar down there?

[Brendan W]

The devil in the detail. I have the older reservoir with the high level return and self disconnecting internal elbow.

[Paffel]

In which case, the theory is still sound, I may have to just see where I can free up the return hose and pop a container where it fits. I'll move the coolant expansion tank out of the way and see how much freedom I can get. Alternatively I'll connect a hose to the return hose and use the extra length to run it away from the car.

Off work tomorrow so a job for the morning I feel. I'll report back with what worked for me.

[cheshired5]

Total capacity of pas system is roughly 1.1 litres.
Reservoir at max dipstick is roughly 600ml.
So.......if you leave all hoses in place and drain and fill, you'll remove 50% of the original.
Do 20 lock to lock turns in between to fully mix the fluid and repeat.
Second drain will remove 25% of original ATF, third will be 12.5% and fourth 6.25%.
Four drain and fills, 93% of the ATF is gone and no pipework has been disturbed and no tools or special piping has needed to be bought.
Do a fifth and sixth drain and fill for good measure (£30 total) and I'll bet your fluid will be as green/blue as the Caspian Sea.