Early morning PAS issue

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Aerodynamica
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Early morning PAS issue

Post by Aerodynamica »

I have recently been getting rough, notchy steering after drivig off from an overnight start. It seems to be low on assistance and just feels dead. It then seems to slowly come back to life after some many miles..

I know the HP pump is not at its best but this is a new symptom.

I'm certain I have heard of this problem before somewhere but can't recall what the possible cause was.

Anyone shed any light on this?
Graeme M

CX 2400 Pallas LPG
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Mk1 Xantia 1.9TD SX

'c'est hydropneumatique'
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jonathan_dyane
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Re: Early morning PAS issue

Post by jonathan_dyane »

Aerodynamica wrote:I have recently been getting rough, notchy steering after drivig off from an overnight start.
They all do that squire ;-)

Well maybe not all, but many of them, particularly after a cold night. Although the temptation is to jump into the FDV, the most likely candidate, assuming filters and LHM are clean (which I'm sure they will be knowing your enthusiasm for keeping the hydraulics tip-top) prime suspect is a slightly tired HP pump.
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Post by BX Bandit »

Or pinion valve!
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Post by classic2cv »

my car does the same

i have to manover my car out of my yard in the mornings

i find that if i turn the motor off when i go to shut the gate the steering seems to sort itself out

when i restart the car it's ok for the rest of the day :D

i think that the system needs a bit of time to build up a good head of pressure after lifting the the car which may be the case for the old HP pump
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Aerodynamica
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Post by Aerodynamica »

Cheers for the replies!
i think that the system needs a bit of time to build up a good head of pressure after lifting the the car which may be the case for the old HP pump
- only thing about that is that the other hydraulic bits are quite 'responsive' and the PAS gets a constant stream from the HP pump whereas the rest gets fed upon demand by the accumulator.
Or pinion valve!
O shyte I knew that would be said!! is this as much of a cnut to change as I think?
Graeme M

CX 2400 Pallas LPG
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Mk1 Xantia 1.9TD SX

'c'est hydropneumatique'
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Post by jonathan_dyane »

Aerodynamica wrote:Cheers for the replies! - only thing about that is that the other hydraulic bits are quite 'responsive' and the PAS gets a constant stream from the HP pump whereas the rest gets fed upon demand by the accumulator.
We-ell, AFAIU, the issues arises because, of course the steering system of the BX is essentially the same type of conventional PAS as fitted to Pugs. As such, it demands high volume, rather than pressure, the purpose of the FDV being to provide a lower pressure supply which bypasses the accumulator. When the pump becomes tired, the 'Citroen' functions (i.e. brakes and suspension) remain to work fine, as the accumulator is able to maintain a reserve which effectively masks the pumps defficiencies. The PAS however, with it's need for high volumes of hydraulic fluid is less forgiving, and the result is loss of PAS in that rather exciting 'notchy' manner. I know you have just replaced the pump, but I would most certainly be trying another and seeing if symptoms change before resorting to changing the pinion valve. A leak in the supply hose from the reservoir to the pump may cause similar symptoms too...
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Post by BX Bandit »

If it's pinion valve then no it's not a big biggy really. 2 unions and 2 M8 capheads (I think!). There's the obligatory PITA flexible coupling (which if you have an original with secured studs) is not that much of a PITA. But if you have a GSF (for example) coupling then you need to change into Mr Tickle and have exceedingly long arms (either that or a wrench monkey or mole grips)
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Aerodynamica
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Post by Aerodynamica »

Understood doods
Graeme M

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Post by Alastair »

I find if you put a secondhand pump on off a NON power assisted car, as long as its a lowish mileage model, the power steering will work fine again in my experience. This is because this pump will have done less work over the years than one from a car with power.
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Post by DavidRutherford »

My BX does this a lot, worse when it's cold. The PAS feels like it almost fails, and then bursts back into life. I'm now used to it, but it can catch other drivers out.

I've a feeling my rather manky LHM doesn't help. How is yours Graeme?
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Post by Aerodynamica »

The fluid was changed as soon as I returned from yours a couple of months ago - it's still clear and the filters (cleaned at the same time) are clear too. The HP pump was weak and the one I got from Tim is only marginally better.

Alistair, that's a good thought - the non-PAS type is I believe, the same pump but never has had to do as much work over all. I'll be on the look out for one (if any exist..)

Just completed a trip to Bradford and back with some Bradford area touring (to a CX man's car graveyard for bits) and the whole day the PAS worked better than it has of late.
Graeme M

CX 2400 Pallas LPG
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Mk1 Xantia 1.9TD SX

'c'est hydropneumatique'
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Post by docchevron »

Twas a tad warmer today mind!
My TD is the same, in the cold weather the PAS is a tad lumpy for the forst few minutes, and that has a new FDV, PR and pump.
It's fine when the ambiant temp is above about 7Deg C though..
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Post by Mike E (uk) »

I think LHM gets thicker when it is cold, so the pump struggles to supply enough when it is worn.

A new pump is expensive, but it cured this problem in my car.

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Post by Aerodynamica »

Well it has now developed a new feature - the constant hissing is still there but it has changed! it now (sometimes) hisses unevenly like a sort of staccato. Still goes away if you rev up. I think the pump is only using a couple of its pistons.

new pump needed then.....
Graeme M

CX 2400 Pallas LPG
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Mk1 Xantia 1.9TD SX

'c'est hydropneumatique'
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Post by docchevron »

Does the pump rattle if you turn the wheel with the car stopped?
I'd say your right though, new pump...
Cant help there I'm afraid..
I'll keep an eye out though.
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