The ULTIMATE power steering thread

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Kitch
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The ULTIMATE power steering thread

Post by Kitch » Sun Nov 26, 2006 10:43 am

Right tech-heads....crack a can open and listen up....

I'm going to be launching alot of my hard earned wedge at the 16v in the next couple of months. The radius arm bearing is done (thanks again Doc) now its the PAS that needs to be fixed.

The brief history:

When I first bought the car, it worked fine. However after a couple of months, I noticed that if I hit the brakes very hard I would momentarily lose PAS for a few seconds afterwards, after which it would return to normal. This happened steering in either direction.

I flushed the tank and filled with that Hydro orange flushing stuff. Then one night, in normal driving conditions the PAS died totally with no warning. Not bias to any particular direction, just disapeared altogether! Its been like this since.

When I blew the engine, I rebuilt it using a known good FDV, a known good HP pump, a decent PR, a new accm sphere etc. I emptied the flush out and refilled with new LHM, but no joy.

To this day there is no life whatsoever from it. With the engine running, if you put it on full lock you can hear a quiet hissing, so something is working! But I don't know what to do and wear to start. Sadly my knowledge of the steering setup ends at the FDV :lol:

There are no leaks to speak of, nothing major anyway. There are traces of LHM on the ram piston itself, but only a very small amount.

If anyone can spare some thoughts I'd be really grateful. In the worst case I'll just have to bite the bullet and fork out to send it into Dorys with a signed blank cheque! It needs sorting, it really ruins the car.

Thanks

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cavmad
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Post by cavmad » Sun Nov 26, 2006 11:16 am

Kitch, as I`m sure you`ll already be aware my technical capabilities are awful but I`d suggest that the FDV may be at fault. Appreciate you`ve replaced it with a known good one but I`m wondering if it was `just one of those things` and it`s now packed up?
Sorry if that sounds a bit lame mate but it was definately at fault on my old estate.
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tim leech

Post by tim leech » Sun Nov 26, 2006 11:18 am

Sounds a possibility, sometimes good used parts do go off when being sat for a while, I always buy new when I can, that way you know its pretty much going to work and if it dont you can get your pennys back!

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Post by jeremy » Sun Nov 26, 2006 11:30 am

There is a nice description of its operation in the workshop manual (section 10) which can be downloaded from Bob Smith's site.

Section 11 is rack testing and overhaul.

http://www.rwbsmith.plus.com/citroen2/steering/

I would start looking at the return from the rack and see if the constant idle flow is there.

The steering is the first thing to fail with a weak pump as it demands a very high volume of high pressure LHM.

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thanuttiscotsman
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Post by thanuttiscotsman » Sun Nov 26, 2006 11:32 am

hi there,
there is a sticky around here somewhere i think about overhauling these things instead of buying re'con etc. your other option may always be to change the whole rack. but id change the other first.

rossco
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cauchoiskev
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Post by cauchoiskev » Sun Nov 26, 2006 2:03 pm

Personally, I've become very wary of using Hydraflush, unless I know that has been regularly used on the car in the past.

If not, it tends to release a hell of a lot of crud into the system, in the form of very fine silt, which is not caught by the filters, and the FDV seems to be particularly sensitive to this dirt.

I have found this silt in the bottom of the reservoir in the LHM which replaced the Hydraflush. It would seem that once the crud has been loosened, it keeps on dirtying the LHM for some time after the Hydraflush has been removed (that's my theory anyway...). Apart from the fact that you can't completely drain the LHM in any case, so some of the dirt remains.

In other words, the system will not be clean until the LHM has been flushed at least twice after Hydraflushing an old, dirty system.

I think you may have to clean out your FDV and replace the LHM again to solve your problem (have a look in the reservoir to see if the LHM is clean in the bottom). It could also be the pump, but I would have expected the steering to become gradually heavier rather than suddenly failing outright...

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Post by sleepy0905 » Sun Nov 26, 2006 4:25 pm

As you have already replaced the pump,FDV and LHM i would have a look at the pinion valve or the unlikely one (unless you are vanny who just pops them :D) the Ram :lol:

Sorry vanny just couldn`t resist it.
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Post by tom » Sun Nov 26, 2006 4:56 pm

The problem occurred at first when the brakes were applied, Power steering was lost for a few seconds so the accumulator was dumping all its fluid when braking and the pump flow was all going to the pressure regulator in order to fill it up.

This means that the doseur valve is passing too much fluid when the brake is applied. This is the only part of the braking circuit that leaks back into the tank, so it must be here. To test, take an empty 10mL syringe (50p from the chemist,) and remove the return from the reservoir. Start the engine and time the return flow. More than 3.5cc/ minute and it is out of spec. It will rise if the brakes are applied, and I strongly suspect that this is the cause of your faulty power steering.

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cauchoiskev
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Post by cauchoiskev » Sun Nov 26, 2006 5:32 pm

This is a very interesting thread !

Tom, I also thought about the brake doseur, which does indeed leak when it's on it's last legs (before reconditioning). However, to completely shaft the power steering, even when the brakes are not applied, that must be one hell of a leak ! No need for a syringe, pull off the return hose and it will be flowing like the Falls of The Clyde !

Also, I would expect the rear end of the car to be permanently low if the brake doseur is as leaky as that. And the pressure regulator will be ticking like Big Ben.

Hopefully, Kitch will keep us up to date...

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Post by Kitch » Sun Nov 26, 2006 6:07 pm

Actually the rear of the car does sit a little low. Not on its arse as such, but looks a bit lower than it should. PR ticks every 12secs, although thats with a Xantia accm sphere....so you'd think it would tick a bit less than that.

Does anyone know which return hose is the doseur (sp) valve one? And I'm right in thinking that if I hit the brakes and fluid comes out of this return at the same time, that could be the issue?

Cheers

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Post by DLM » Sun Nov 26, 2006 6:14 pm

From memory yesterday watching Tom doing diagnosis on my car (and its doseur) - it's the toppermost return more or less in the middle of the return pipe grouping at the reservoir. Otherwise - go look in BX DIY - I'm sure it's there.
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cauchoiskev
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Post by cauchoiskev » Sun Nov 26, 2006 8:41 pm

That's the one, "C", bang in the middle :

Image

(C) Y. Narabayashi

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Post by jeremy » Sun Nov 26, 2006 8:53 pm

The PR sould tick at a minimum every 30 seconds - and preferably at longer intervals.

I don't see that the precise nature of the accumulator is going to make much difference so we're down to basics here -

There are 3 ways LHM escapes from the accumulator - onwards to the brakes and suspension, down the centre valve - and backl the way it came through the non-return ball valve.

If its going onwards - if the car is static - it must be going back to the reservoir somewhere - and can be found via the return pipes.

There is a labelled diagram of the return pipe stubs in Haynes. Must say when I tried to follow it I didn't have much luck! There are also some illustrations I think on the Citroen DIY site.

If the back is low it could be due to height corrector linkage problems. However when I had FDV problems I had trouble getting the thing to rise - and the trick was to hold the steering wheel against resistance - whereupon the pressure would increase and the car would rise. It seemed to stay up but I'm not sure that it did all the time.

I assume you have Haynes - if not you can download the whole thing in English from here:

http://www.citroeny.cz/servis/servis.htm

Its the top document under BX

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Post by docchevron » Mon Nov 27, 2006 12:44 am

I had the same thing happen not too lonfg back with the TD and it failed the MOT for it. I changed everything, and I do mean, everything!

The last thing I changed was the FDV since I was convinced it wasn't (It was only 8 months old...)
The second hand replacement FDV I fitted came off a good car, known to be good, but the steering was still sh!te. Changed FDV again, PAS returned immediatley!
I had similar issues a while ago and it was the PR. The output line pressures were through the floor, and although the brakes and suspension seemed ok the relief valve was cutting in every 10 secs or so.
I'd suggest changing the FDV, then the PR.

Dont believe it's your pump for a second. My valver had a knackered pump on it when I got it (infact, everything on it was knackered!), and the steering would lock up. But it's easy to tell on the valver as the pump rattles so badly you can hear it over the engine and stereo!
Your pump makes no untoward noise so I'd be amazed if it was an issue with that....

Cheers
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Post by Kitch » Mon Nov 27, 2006 5:10 pm

Cheers guys.

Where can one purchase a reconned or brand new FDV and PR? It might just be worth doing so I KNOW its done then.

After I've checked this doseur valve pipe of course....thats free :lol: