New Pressure Reg On Ebay

[Peter.N.]

Citroen Xantia /XM/BX Hydraulic Pressure Regulator Item number: 260208222781

Peter.N.

[jorgy9]

Hmmmm....strange this doesn't generate more itnerest as it's a precious thing to have for all of you who drive standard-steering-assistance XMs. Just putting this in the place of your old one is 99% likely to make everything work better in your car -well, almost everything...-. Might be the key repair for getting back that soft suspension...and steering assistance to feel strong like a 1,000-mile car again...and car not needing ages to lift in the morning...and the regulator not clicking like mad although you've just put a new accumulator....Is this all not worhtwhile of 20-odd quid and half an hour of your time????

(I'd have already bid on that but I drive a DIRAVI so got the other model (just 2 of them cover all the Cit range) ...Plus, I've sorted out my old one -i.e. I readjusted the pressure range to 145/170- and got back my soft suspension from one moment to the next...Pressure range had naturally dropped to 138/157 bar in my 138,000miles car...)

cheers
George

[Peter.N.]

Hi George

Would that also affect the weight of the power steering, mine feels a little heavy compared with my sons and I have just bought a 2.1 hatchback, for spares, although its a crying shame to scrap it, it drives like a dream (if you dont mind not having a clutch), and that is even lighter. I have already changed the regulator twice, but both times with secondhand ones.

Peter.N.

[jorgy9]

Hi Peter,

Yes it will, provided the Flow Distribution Valve is also OK, you understand how it goes, these 2 work together. Thing is, with buying second hand things you never know whether they are better, same or worse than the one you wanted to replace! Pressure regs are usually unbreakable and it's a crime to through them away -they may only need those 2 seals renewed from time to time- BUT the 2 springs in them that regulate cut-in and cut-out pressure DO weaken with time, result is the pressure range your whole system gets becomes lower and lower and lower than the specified 145 to 170. In my case I had the tools to measure and add the shims necessary to get this back to standard, but I know most of us don't have access to such a tool. Hence I think £20 for a new one (that will produce the right pressures) is a great opportunity...

With that one, and a refurbished FDV, your Cit hydraulics will work like new!

cheers
G

[jorgy9]

ps. just wanted to explain that, keeping a high (as specified, 145-170) pressure range is important because, when the regulator has cut-off (i.e. accumulator has reached 170 bars) it is both the pump and the accumulator pressure that feed the steering (that is, when you turn it). So at that moment it is in your interest to have as higher a pressure reserve as possible. If your regulator cuts-out at, say, 157 bars (like mine did) the steering valve will have less immediate pressure available to start with (less assistance), and second, it will run out of assiting pressure quicker (i.e. accumulator sphere pressure dropping to cut-in point). Then, if the pressure regulator is in a cut-in phase (ie filling up the accumulator), and you ask for steering effort, the steering valve will only be supplied by the pump, which will divert its supply from filling up the regulator. This means the steering will only have the efforts of the pump available. Also, it means that in the meanwhile the brakes and suspension are using pressure which is not being replenished. So, again, it is in your interest to find yourself as less often as possible in a phase where the regulator is filling up (has cut-in), i.e. 1/having a large spread of pressure range between cut-in and cut-off points (my regulator offered a range of 20bars when this is specified to 25 bars ideally [+20%, trust me it makes a difference]), and 2/this range being higher rather than lower (my p.reg:137-157bar, new:145-170) so all the hydraulic components will have plenty of pressure available (so that steering can steal more pressure from them, as happens in the cut-off phase of the regulator). Briefly, the FDV was a solution to avoid putting a second pump in the system, which they've finally done with the 6+2 pump.

Without me describing much, perhaps you can understand the function from the photos below. The upper panel is how it works when the pressure regulator is in a cut-in phase (ie it is filling up). The lower is when the p.r. has cut-off (i.e. has reached max pressure and is emptying it). In both cases, left-hand photo is when the steering is in stright line (or when there's no steering effort demanded, in my opinion) and right-hand is when you're turning the wheel.



cheers
George

[jorgy9]

Also, before trying to refurbish the FDV, you could try and give it a bit more pressure. There's a screw that adjusts the pressure going to the steering valve, on the FDV. Normally you have to plug in a gauge in line and measure 135 to 140 bar on the outlet to the steering valve, with the wheels turned at lock. But you could play a bit empirically till you get a better steering -although you do understand the risk of doing so without knowing what pressure you are applying to it-.

Finally, and independently of anything else, I would definitely recommend a good session of Hydraflush Peter, specially if you've never done it before, it might cure everything, but you'll have to leave it for long (many thousand miles). The FDV has a couple of (or 3?) springs, and 2 piston valves, all this WILL have become sticky even if you have been changing LHM in due intervals -the system just NEEDS a "deep" cleaning from time to time-. LHM is much incapable of self-cleansing.

cheers
George

[Peter.N.]

Hi George

Thanks for the info. I understand the basic operation of the regulation/distribution arrangement but obviously not to the extent that you do.

The steering never 'runs out' of pressure, its just that it always feels heavier than the other cars in normal driving. I have changed both the regulator and FDV twice, not for that reason but because of frequent pump cut in (15-20 secs) and an almost continual hissing at idle which seems to be due to the pump not actually cutting out at all as it stops when a few revs are applied, this has improved the cut in time a little but not the steering. And, 'yes' I have tried two new accu spheres.

I loved the 'diravi' on the CX, I wish they had put it on these!

Peter.N.

[jorgy9]

Hi Peter


1/ I remember you drive with your tyres lower on pressure, does your son practices the same, if not is this perhaps why your steering feels heavier?

2/ Do all 3 XMs you posses do the same continuous hissing noise when on standstill/steering straight? I've only heard one XM with an FDV and it was also doing it -but I suspect it's not in a healthy hydraulic state-.
(As you can see on the top left-hand photo, when the regulator is in a state of filling-up (cut-in) almost all pump output is directed towards it; only a small amount (normally) goes to the steering valve (so it can detect at any moment the demand of assistance). But it's difficult to say why your p.r. never cuts-in unless you take the revs up -the problem could be anywhere as I'm sure you know...-)

3/ How do all your 3 XMs compare for ride softeness? Do you see any correlation with the previous?

15-20secs is definitely too low for a new accu sphere. I was at 14secs which has now improved to 28 secs after 5,000 miles on hydraflush -no other intervention-.

cheers
George

[Peter.N.]

Hi George

The tyre pressures make little or no difference, I've tried. The red one also hisses when idling but the steering feels much nicer so I dont think there is a direct link. The steering is not really heavy, I probably wouldn't have noticed it had I not driven the others. I thought that perhaps the red one was exceptionally light, until I drove the hatchback, that's the same.

The green one (with the problem) rides very well, a little wallowy if anything, but I have fitted comfort spheres. The red one is OK with normal spheres, the hatchback seems to give a remarkable ride seing that there is no descernable movement in the rear suspension! Flat spheres I assume, I havn't had it on the ramp yet, as without a clutch I think it could be a rather perilous operation

I think that the hydraulic system, certainly on the estates is fairly well worn, the suspension drops fairly rapidly, but comes up promptly on starting again. It's been like this pretty well since I had it and as I have covered over 60k in it, I tend not to worry to much - but it would be nice to have it hiss and tick free!

Peter.N.

[jorgy9]

Hi Peter

if nothing else then, I'd put the green one on hydraflush, leave it and see. It can only do good.

cheers
George