Xantia S2 power steering pipe repair

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CitroenCrazy
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Xantia S2 power steering pipe repair

Post by CitroenCrazy »

In response to Eb's query, a few words (and pictures) on how to fix a leaky power steering pipe an a Series 2 Xantia
(I've never owned a Series 1 example, but I hear this bit of pipework is completely different on the earlier cars, so this doesn't apply).

The part we're talking about is item 1 on this diagram
Pipe overview.jpg
And this is what it looks like off the car
PAS pipe off the car - RHD 2.jpg
Different versions of the pipe exist for diesel, petrol and V6 engines and the section between the flexi hose and the rack is obviously much shorter on left hand drive cars, but the principles remain the same.

The most common problem is that the section that runs through the nearside wheelarch rusts through, for example here, where it's held by a plastic clip.
03 pipe route 2.JPG
The easiest fix is therefore to replace just the section after the flexi hose. This is very straightforward and can be done without any Citroen-specific tools.
It turns out that the connection to the rack is a standard bubble flare, and as shown in picture 2, the pipe is 3/16", not the 4.5mm or 3.5mm commonly found on hydropneumatic Citroens. Any garage will be equipped to make pipes like this and DIY tools are not expensive.
IMG_2464.JPG
So, the idea is to cut the pipe about 70mm from the end of the flexi hose, make a bubble flare in the stub of steel pipe, use an in-line union and add a 1600mm (*) section of 3/16" cunifer with a further bubble flare at each end. (* = for RHD cars)
IMG_0911.JPG
Just don't make the mistake I did the first time and fail to leave enough room to accomodate both the union and the flaring dies at the end of the flexi pipe
pic 4 - space for flaring dies.JPG
If the pipe is in poor condition right up to the flexi pipe, a repair can still be made, but it gets more involved. For brevity, I'll skip that option for now, but come back to me if you need to know more.


Of course, there's always the option of taking the whole thing to the nearest industrial hose supplier and saying copy that please.
Just be aware that the original pipe assembly holds a hidden secret that will not be included in your aftermarket copy.

I wanted to understand how the swaged joints between the steel pipe and the rubber hose are made, so I sectioned a joint from a scrap pipe.
pic 8 - sectioned joint.jpg
I certainly was not expecting to find this 1.5mm diameter flow restrictor built into the joint on the pump side of the flexi pipe.

A couple of poeple have reported on this very forum that they'd noticed pulsing of the steering on full lock after fitting a replacement pipe assembly, which is, I'm sure because this flow restrictor is missing. Ok, it's by no means disastrous, especially compared to the alternative of having a car off the road for want of a pipe, but I think it shows the merit of repairing what you have, if you can.

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ksanturion10
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Re: Xantia S2 power steering pipe repair

Post by ksanturion10 »

CitroenCrazy wrote:
13 Oct 2020, 20:32
I certainly was not expecting to find this 1.5mm diameter flow restrictor built into the joint on the pump side of the flexi pipe.
Kind of a damper I presume, because of the 6+2 pump. There should be an increase of the velocity of the fluid at 1,5 mm section, given the flow and the pressures are the same at both ends of it. So, the goal should be smooth delivery of the fluid to the rack :)
CitroenCrazy wrote:
13 Oct 2020, 20:32
but I think it shows the merit of repairing what you have, if you can.
"if you can" is the culprit here :D

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CitroenCrazy
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Re: Xantia S2 power steering pipe repair

Post by CitroenCrazy »

Update - to keep everything in one place

In Eb's latest post, he mentioned this >>mine had a small hole right on the bend where it goes from metal to the rubber pipe at so looked awkward to repair <<

So perhaps I should expand on what we might call a "phase 2" repair, when there's not enough good pipe left to join to after the flexible section.
I've done this a couple of times. The first one was still fine when the car was scrapped over 100,000 miles later, the other is still going.


The solution in this case is to drill and tap the swaged joint at the end of the flexi hose, which is just a little bit more involved.
You will need a tool to make a Citroen 4.5mm flare and approximately 1700mm (for RHD) of cunifer in that size

The whole pipe has to be removed from the car.

Saw off the end of the pipe where it exits the swaged joint
01 saw off the end.JPG
Drill the end of the joint to 6.8mm, the tapping size for M8, 18mm deep. Don't go any deeper.
03 ready to tap.JPG
Tap the hole M8. Use a taper and a bottoming tap. Grease the flutes of the taps to try to retail the chips.
Blow the pipe out with an air line from the pump end

Drill out a Citroen 3.5mm union to 4.5mm.
If you happen to have some of the aftermarket versions with a 10mm head, one of those would be perfect, but the standard ones are ok too.
Put the modified union on the pipe and flare the end in the normal way
My memory is fading here, I think I used a 3.5mm pipe seal, eased on with a bit of LHM. Or maybe I squeezed a 4.5mm seal in, I can't remember.


Now, we have to put a bubble flare on the other end of the pipe. This is slightly tricky and it pays to practice first on a test piece of cunifer.
The problem is that the dies for the bubble flare are intended for 3/16, ie 4.75mm and they won't grip the 4.5mm pipe.

The first time I did this, I wrapped the pipe with aluminium from a coke can. There's just a little experimentation required to get the amount right.
(Since then, I've made a custom pair of dies to hold 4.5mm pipe for a DIN bubble flare, but that's another story)
As long as the pipe can be gripped, the bubble flare will be formed perfectly

As always when flaring pipe, don't forget to put the union on first.............we've all done it.........some of us many times :-)

So, there's an obvious question, why bother modifying a 3.5mm union to suit 4.5mm pipe, when Citroen make perfectly good 4.5mm versions ?
The reason is that 3.5mm unions are M8 and 4.5mm unions are M9.

If we recall what's inside the swaged joint, there's an inner and an outer section, all squeezed together at the top to make a high pressure seal.
The inner section is only a whisker over 9mm diameter, so if you tap it M9, there's not that much left holding it together.
DSCF3399 - Copy.JPG

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CitroJim
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Re: Xantia S2 power steering pipe repair

Post by CitroJim »

Excellent :)