PAS tank removal and replacement

[moorgate]

Look down on your Power Steering header tank. I don't mean, sneer at it: get directly over the top of it with a strong light and look downwards. Do the long sides of the tank look swollen outwards to you? Then you have been suffering from a suction hose leak. This seems to produce three symptoms:

- noisy pump

- weak power assistance to the steering

- leaks from all kinds of parts of the system

If your tank is swollen, then very probably the mysterious bit of gear inside it is loose and rattly (though you can't prove this until you get the tank out), and you may have topped it up a bit even though the system doesn't seem to be leaking enough to leave drops on the ground or undertray.

This was my fate, after some mysterious force left the suction hose loose at the PAS pump end (the suction hose is the one that's held by a soft metal clip directly over the top of the PAS pulley). Once the header tank goes over a certain level of distortion, it starts to leak from the seam, becuase the full-enough level for the fluid is above the level of the seam. And maybe that mysterious part inside it falls out of kilter and starts being rattly: who knows.

Anyway... I replaced mine. This was easier than I thought in some parts (managing the fluid was dead easy, armed with a 20cc syringe), and harder in others (wait for the punchline here!). First observation is that the tank seems to hold about 600cc or so - I had a regular rhythm going of slamming the syringe in, suck up, squirt into a ploycarb drinks bottle, back again... and once you have done this until the syringe won't reach no more, the fluid level is low enough that you can get the hoses off without major fluid dramas. Just pull them and prop them so their ends face upwards, once you get them off.

Ah yes, the getting-off bit. By the time you can tell that the PAS tank is swollen, you may have the problem I had, that the seam on the tank has hooked itself under the seam on the coolant tank! This is a problem, because the coolant tank is what the PAS tank is supported by, on two angled slots and a central, top clip. A swollen tank is not going to come off the way it shows in the videos or the manual...

In the end I decided to apply my BFO screwdriver to those angled slots on the back of the PAS tank. I was intending to mash them, sicne the tank was clearly already dead, but the fact is that the whole assembly is made of soft enough plastic that the slots will disengage without damage to either coolant or PAS tanks. The fact it was a warmish day probably helped with the flexibility.

Putting things back together was a breeze; I had a good look over the suction hose before I did up the jubilee, but it seemed unsplit, and of course my replacment, unswollen tank from a scrappy slid into place perfectly. The fluid isn't like brake fluid - I was completely sloppy about putting it in the tank, and ended up with about 10% left in the bottle, since someone had evidently been topping up the system with the tank all swelled up! A couple of waggles of the wheel from side to side and everything was kosher.

And true to form, inside the swollen tank was a loose rattly object, of about the mass of a couple of plastic bottle-tops. The good tank didn't rattle when shaken empty: the bad tank, did. And despite the seam leaking and me being in just the right mood for a bit of destruction, I couldn't split the tank to have a look at what the rattly thing actually is: which is a pity, because it's the thing that justifies doing the tank swap.

[4candles]

What punchline?

Was your PS noisy?
Is it noisy now?


My XC tank is leaky, i also have noise and i also have weak PS.
My V70 is devoid of any issues and its running lovely Dextron RED fluid?

[moorgate]

Originally Posted by 4candles

What punchline?

Was your PS noisy?
Is it noisy now?


My XC tank is leaky, i also have noise and i also have weak PS.
My V70 is devoid of any issues and its running lovely Dextron auto fluid?

yes it was, very loudly and with loads of extra vibration, and now it's not. The "punchline" was the bit about how to overcome the two tanks beling locked hard together by the swelling and the seams.

[4candles]

Originally Posted by moorgate

yes it was, very loudly and with loads of extra vibration, and now it's not. The "punchline" was the bit about how to overcome the two tanks beling locked hard together by the swelling and the seams.

Excellent, i will do this asap instead of swapping pump over from V70.

Aghh, i sort of thought that was the punchline,,, and yes they can be a biatch to remove if they are swollen, remarkably resilient to normal un-hooking efforts!

Cheers

4c

[Brendan W]

Locked together they are beyond reason. In spite of the spread around the middle and a bit of a weep at the outlet spigot and another at the cap my p/s is as quiet as a church mouse and behaves impeccably.

[4candles]

Originally Posted by Brendan W

In spite of the spread around the middle and a bit of a weep at the outlet spigot...

ave you been spying through my toilet window Brendan?

[Dancake]

Why go to all that hassle just to replace the fluid reservoir with another pre-facelift prone to swelling pos? Get yourself a post-facelift reservoir, then fit and forget. Best about it is they're both the same price direct from Volvo at around £35

[4candles]

Originally Posted by Dancake

Why go to all that hassle just to replace the fluid reservoir with another pre-facelift prone to swelling pos? Get yourself a post-facelift reservoir, then fit and forget. Best about it is they're both the same price direct from Volvo at around £35

Got a part number for that or are they only supplying the newer ones anyway?

[bournricha]

Nice stream of consciousness style Moorgate !We could really enter your head there ,dribbling spiggots and all

[moorgate]

Originally Posted by Dancake

Why go to all that hassle just to replace the fluid reservoir with another pre-facelift prone to swelling pos? Get yourself a post-facelift reservoir, then fit and forget. Best about it is they're both the same price direct from Volvo at around £35

well: because actually, the hassle was getting the old one out, not putting the new one in, and now I know where to insert the screwy blade to produce the dull DOINK of a releasing flange. Unless the later model has some very clever way to depressurise/defoam (in which case it's just hiding a leak which you should be fixing anyway), I don't see the gain - other than the difference between £35 and £16...