Feldiagnos om trasig pump

Mats H 2004-06-05: Jag har lite funderingar på en Bx 19 vars ägare menar att hydraulpumpen är väck. Vad jag förstått är det inte så vanligt fel. Hur yttrar sig fel på hydraulpumpen? lägger den av helt? missljud? läckage? eller vad händer. Kanske allt men är det något som är mer vanligt. Jag har inte sett bilen själv utan det jag funderar på är om det kan vara något annat som föranlett ägaren att misstänka pumpen.

Brede H: Ja, det hat til og med hendt at Citroenmekanikere har stilt denne diagnosen - og det har vært galt. Vanlige alternativer er hydraulreimen, denne er slitt og/eller slurer på hjulet. Skal være adskillig strammere enn de fleste tenker seg. Videre vil dårlig hovedacc.kule også ofte oppfattes som pumpefeil, grunnet hyppig tikking/jobbing. Og selvsagt det "banale" - at det er nok LHM-olje, ren og uten skitt i systemet som medfører at pumpe må jobbe ekstra hardt og belastende. At det av en eller annen grunn er luft i systemet er også en mulighet, litt "Citaerobic" ordner i så fall det. Hva annet som kan foranledige at pumpen er mistenkt er ikke godt å vite, vil jo være avhengig av kunnskapen til den som har uttalt seg. Selvsagt, pumpen kan være ødelagt, men det er nesten bare teori.   Kjell H: Pumpen är bra på att pumpa,men dålig på att suga. Om det är minsta lilla hål i sugslangen(den grova) eller filtren är för skitiga,så fixar den inte det.Hål i filtren kan ge luftbubblor som får pumpen att låta illa.   Bengt W: Pumpen KAN vara dålig även om det nog inte är så vanligt, i alla fall inte på BX. Samma pump satt på XM fram till 95 och den större och tyngre bilen blev lite jobbigare för pumpen så på min la den av. Det är svårt att märka skillnad på problem med pumpen och andra delar i matningen på hydrauliken, det mesta brukar visa sig som dålig eller ryckig/ojämn servoverkan på styrningen och att det ibland kan ta väldigt lång tid för bilen att lyfta. Problemen är ofta temperaturberoende. Om det inte är pumpen kan det vara fördelningsventilen till styrservot eller tryckregulatorn vid huvudackumulatorn, men det är nog sällsynt.

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Inget hydraultryck p g a punkterad klocka

Peter L 2000-09-12: Min T2'a har stått och vilat några veckor och idag när jag skulle starta den ville den inte resa sig. Inget tryck till styrning eller bromsar heller. Pumpen snurrar och ingen hydralvätska har läckt ut. Någon som har några ideer?

Anders (DK): Lyder ganske enkelt som at pumpen har tabt ansugning fra reservoir. Det K A N skyldes en lille sprække i pumpens sugeslange. Løsne den tykke slange til pumpen ved reservoir-enden, og fyld slangen op med LHM, sæt slangen på igen, og prøv om pumpen kan suge til nu. Du skal selvfølgelig være sikker på, at reservoir er fyldt næsten helt op, når bilen er lav. Giver det ingen resultat, har du sandsynligvis et problem i regulatoren. Det kan ganske enkelt være trykafladeskruen, som er løs.

Peter L: Jag gjorde som du sade. Jag lossa slangen och fyllde på LMH, slangen var hel och bilen låg kvar på marken. Skruven i regulatorn satt fast. Fungerar pumpen? Provade att lossa röret mellan pump och regulator och det kom först luft och sedan vätska alltå fungerar pumpen. När jag sedan satte tillbaka röret reste sig bilen upp. Cittran lagade sig själv eller...? Jag förstod ingenting. När jag sedan tog ut bilen på en provtur gavs svaret, fjädringen på vänster bak var stum. Alltså punktering i klockan. Luften som jag släppte ut när jag lossade röret var gas.

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Järnfilspån i hydrauloljebehållaren?

Dennnis 2001-02-23:   Jag håller på att byta hydraulolja på en CX -80 och när jag rengjort filter och behållare så förekommer det en del järnfilspån i behållare och filter. Jag undrar om detta är fullt normalt eller om det är så att någon komponent i systemet är på gång att säga upp sig?

Johan G:   Helt normalt slitage! Det är de sju små kolvarna i pumpen som helt enkelt slits med åren. En intressant sak om slitna pumpar: om bilen sjunker snabbt efter parkering brukar det vara ett tecken på en sliten pump. Oljan smiter i så fall bakvägen genom pumpen. Man får BX-syndromet, låg bakvagn.

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Awkward steering problem

John (BE) 2001-03-17: In a few occasions in the past it seemed like the pressure was falling down when I parked the car, but the pressure always came back in a couple of seconds. This noon me and my girlfriend were cruisin' a bit and after a few sharp corners, while discussing the perfect handling of the CX, the STOP light and the 'handbrake' light went on at the same moment. We drove the car near the side of the road and after a few seconds I almost couldn't turn the steering wheel. There was no sign of a loss of LHM, not at the motor and not under the car. I placed the car in high position but she didn't raise very well and at that moment there was no clicking sound from the hydraulic pump either. I looked at the lhm-level meter and the level was too low so I decided to put in half a litre of LHM. Nothing changed, no steering pressure and no raising of the car. After restarting and deciding to call my garage I tried once more to turn the wheel and in a glimpse the red lights went out and everything worked again. We drove back home and checked the LHM-level again and it was much too high. So everything I putted in had to be removed again. In my opinion there's something wrong with the hydr. pump (or maybe the steering rack). Does the whole history sound familiar to anyone? CX 22 TRS S2.

Daniel S: From the symptoms - the 'stop' light coming on, steering and suspension not working properly - it's obvious that the pressure in the hydraulic system fell to much too low values. The fact that you didn't hear the pump click (the clicking does come from the pump, not from the accumulator sphere) indicates that for some reason the pump didn't cut in when the pressure fell. The way it normally works is that the pump isn't on all the time, it just cuts in when the pressure gets too low, and stops again when the pressure has an acceptable level. There is a sort of "switch" in the pump that senses the pressure and makes the pump start or stop. It seems to me that this "switch" hung in high-pressure position in your case, so that the pump didn't cut in although the pressure fell below the threshold. I have no idea if a hydraulic pump can be serviced or not. In the worst case, you need a new pump. I'm quite sure nothing else is wrong with your hydraulics. Btw, this is the first time I ever hear of such a defect. Anybody else ever experienced something similar?   Scott R: The switch exists all right, but it's in the pressure regulator, the thing the hydraulic accumulator screws into, rather than in the pump. The regulator may be your trouble, or it may have gotten a bit of dirt in it. Have you changed you fluid recently?   Neil H: I thought the pumped worked all the time and it is the pressure regulator which controls the available pressure? The regulator recirculates the fluid back to the reservoir until the pressure in the systems falls below 145 + - 5 bars then the regulator cuts the pump back in again until a pressure of 175 + - 5 bars is achieved. These can go faulty, for fluid loss (without external leak) check the brake and steering accumulator (the one near the radiator fixed to the subframe) these can hold approx 500cc of LHM if the membrane is punctured. Could be the small filter in the inlet supply pipe to the steering controller.   Alan D: If the pressure falls to too low a value, as yours has, the problem may be: A) slipping belt drive to the pump, or loose pulley (key damaged?) or similar problem preventing the pump revolving. (The clicking noise comes from the effect of the pressure regulator sending the pump output to the high pressure circuit instead of allowing it to dump - at low pressure - back into the reservoir. (The pump works the whole time but only part-time against the high-pressure load.) B) Pressure regulator valve wedged in the 'dump' position by wear, gunge, damage.... C) A sudden and complete collapse of pressure seems not to be caused by blocked filters, but who knows on a CX??? It is difficult to tell the state of the LHM without removing the filters from the bottom of the reservoir. It is not difficult, just messy. D) The pump sucks air through a split tube between reservoir and pump inlet union. Will work OK at high speed, because the air gets entrained in the oil and bleeds away. If you do not have ABS it has no/little obvious effect on the rest of the car, but may make the brakes spongy after ABS operation. The pump may suck air if the resrvoir level is too low. John, do you know that the reservoir level must be checked with the suspension at the HIGH setting??? It can not be correctly checked if the hydraulics are not working well enough to raise the car all the way. E) If the pressure comes back with no further action but just waiting a while with the engine running, the main accumulator - the one attached to the regulator block - may be useless (with a punctured diaphragm). This means that on sudden high steering load, like when parking, the pump has to provide all the power, and it can not, at low engine speed. It needs the main accumulator to be working to sustain the pressure. The steering is the biggest load on the hydraulic system. F) Because this is a CX we are talking about, there are about 47 other reasons for your problem, but nobody knows what they are.   Gabor: The pump works continuously but when it is not required to add pressure to the system, the LHM just goes right back to the reservoir. The clicking comes from the pressure regulator, not the pump. The regulator is the holder the main accumulator is screwed on, thus the click does come exactly from the location where the accumulator sphere is.   Gary M: Could be dirt?

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