When should you change PAS fluid?

[Welly]

My car is nearing 10 years old and I know the PAS fluid is the original from the factory (probably the only thing left that is ), thing is I've never changed the PAS fluid on any of my cars

What do you lot do? leave it alone? change it every few years? inspect it? send it to a Laboratory for analysis?

[markw]

As there's no 'official' drain point provided, I guess they expect it to last the life of the car.

I had to replace mine simply because the servo valve on the rack died and to replace it, all the fluid escapes....

[Rolebama]

I have never changed PAS fluid. After all, it isn't subjected to particularly high pressures. The only checks I know of (apart from level checks), is to get a drop on a piece of kitchen roll and after it has soaked in, check the colour and for any particles. (Which usually indicate component wear). You can rub it between finger and thumb to check for particles, but I don't feel it is 'exact' enough, as I used to have callouses.
Working in garages, FWIW, I have replaced it through component replacement way before I would replace it because it has 'worn out'.

[Welly]

Hmmm, interesting, thanks.

[markw]

In a pdf I have which details how to test the pressure in the system, it states that at 1500 rpm, the pump should be capable of providing 100 bar, + or - 5 bar.
I'd say that was quite high.

[Welly]

I mustard mitt I always understood there was a high and a low pressure side to the system.

Mine has an electric PAS pump (Volvo) and the current it draws is enough to pull down the National Grid, that's what got me thinking about the fluids' quality/lifespan.

Is this the right time to admit to never opening the PAS reservoir cap in nearly 6 years? in my defense I can see the fluid through the clear(ish) reservoir I just haven't 'inspected' it.

Think I'll get it changed along with the gearbox oil as that's due now too.

[steve_earwig]

I've absolutely no idea if it's necessary but I guess it'll give you peace (piece?) of mind if you change it. Unless it costs you a kidney.

[Bailes1992]

The MK4 Mondeo suffers with PAS failure.
The seals in rack degrade and block up a filter in the reservoir. This starves the pump and the rack and causes them to fail.
When I got the car I changed the PAS fluid and reservoir. The filter wasn't replaceable.
I removed all the pipework and blew through all the pipes with an airline. I dripped fluid into the pump and spun it by hand to flush it out.
I then dribbled fluid into rack and got my other half to turn the steering from lock to lock to flush the rack out.
I put it all back together and filled the system back up.
The new reservoir has a removable filter so once a year I drain the reservoir, clean the filter and fill the reservoir with fresh fluid.

So far I've had no issues with my PAS.

[Welly]

I've heard of that on the Fords, I was kinda wondering if my Volford has the same unit.........place yer bets!

[Rolebama]

The ability to work at 100bar is a bit of a misleading comment as the system rarely works that hard. Maybe if you tried to turn the steering with both wheels stuck somehow you would generate that pressure, but probably don't even come close in day-to-day usage.

[Bailes1992]

I've heard of that on the Fords, I was kinda wondering if my Volford has the same unit.........place yer bets!

I've never heard of the issue with Focuses to be fair. I know the Volvo S60, V60 and V70 suffer from it, as do the MK4 Mondeo, S-Max and the Galaxy.

[Welly]

Oh yeah I forgot mines a Focus, might be ok then

[Bailes1992]

Many of the guys on the talkford forum just buy 5 litres of fluid and once a day after a drive they drain and refill the reservoir until they've used all 5 litres.