2.1 Saloon Bad Rear Hydraulic Pipe Leak

[Andmcit]

On a W plate. There's a significant pipe leak just after running off the centre of a rounded
end mounting on the top nearside of the main back axle tube. Not sure if this the anti sink
or the centre sphere but it appears to be 4.5mm diameter pipe with a 9mm pipe nut.

Does anyone know where the other end is jointed to help me determine the best action
of repair before I need to drop the rear subframe?

No access available to even feel the route of the bust pipe!
Looks like not only would the exhaust need removing entirely but the fuel tank is in the
way of the two front subframe mounts...

Andrew

This post has been edited by Andmcit on March 01, 2008 06:43 pm

[Peter.N.]

Hi Andrew

I've just fixed one of those with help from Noz and others. You can quite easily drop the rear subframe and get to them. The one that's gone is probably the sticking up one, all the others are flat on the tube. I cut a piece out of it and replaced it with the aid of a swageing tool and some pipe and fittings from Pleiades. The only real problem I had was getting the end fitting out of the 'Y' piece, having turned the corners off the nut I had to resort to welding a larger nut over the fitting. You will need to hold the piece it's screwed into with mole grips.

If you loosen the bolts on the drivers side of the subframe you can leave it connected that side and completely remove the bolts on the nearside and drop it down (on a jack).

Peter.N.

[Andmcit]

No matter what I try checking from my reference I'm not getting anything on the late
S2 hydraulic back end. There's nothing that shows the item above on the top left of
the rear subframe with this single feed that runs onto the rear cross member! I'm not
finding the corresponding end which would be great to help me determine how to run
a new repair in. Does this in fact drop down onto the nearside sill?

To drop the rear subframe means disturbing the exhaust system which whilst it looks
solid enough I really don't fancy touching and the height corrector selector rod. Plus I really
don't fancy disturbing the main feed run off the nearside floorpan up onto the rear cross
tube; the plastic coating on these pipes where they bend round up onto the subframe
has actually trapped rot where there's a pipe clip bracket and they may not take kindly
to a bit of aggro!

Surely there can't be many pipes in this area on a late S2 that use a 9mm joint which
certainly appears fatter than the surrounding 3.5mm pipes! The offside one's I can see
on the subframe are all 3.5mm and run down from the height corrector and the only
other 4.5 is one I mention on the sill though it'd be a real turn up to see it run the
opposite way to what I can actually see.

Does anyone have a piccy of a removed subframe or a late s2 circuit diagram?

Andrew

This post has been edited by Andmcit on March 02, 2008 12:10 pm

[Peter.N.]

Hi Andrew

I can't help a lot really. The pipe that went on mine went upwards from the suspension tube, then down and to the nearside along with all the other pipes. I joined it under the rear n/s passenger floor as it was easier to get at there, with about 2' of pipe.

I dropped my subframe without disconnecting anything and it went quite a way. It did bend the hydraulic pipes but not a lot. If you dropped it just far enough to see in there I don't think it would do any harm. The only problem I have now is that my hydractive doesn't work - I dont know if the two are connected.

Peter.N.

[noz]

Hi Andrew,

From your original post you seem to have confirmed that the leak is definitely coming from the 4.5mm pipe which attaches to the centre of a sphere which is located on a triangular bracket high up on the nearside of the rear subframe. I can confirm that this sphere is definitely the the Anti-sink sphere. In conjunction with the anti-sink valve they both ensure that the car remains at the same height overnight. The system doesn't completely stop the leaks back to the tank but it slows them to such a degree that you don't notice it falling. The whole write-up on the system starts at page 850 of 1868 in the factory manual. Citroen call it the SC/MAC system.

The 4.5mm pipe coming out of the centre of the anti-sink sphere connects to a Y-piece in the pipe which runs from the height corrector to the anti-sink valve. All of that piping should be visible (relatively speaking) since it does not run to the front of the car. Only the pipes which run to the front of the car go over the top of the crossmember tube and come down to sill level between the crossmember tube and the fuel tank. However, the pipes run together with several others clipped to the 10 O'clock position (ie below the top of the tube on the back side) on the crossmember tube with multipipe plastic clips. Whilst it is just humanly possible to reach these pipes without dropping the subframe it will be nigh on impossible if you don't drop the second from rear exhaust box.

Dropping the subframe and rear exhaust are not nearly as difficult as it sounds. You don't have to disconnect anything. It all just bends as you drop them and springs back into place when you raise them back up again. You are not removing the rear subframe only dropping it about 100mm. Access is improved 100-fold if you drop it. You will spend much longer fighting with access than you would if you dropped the subframe.

I suppose it helped me to see it being done the first time otherwise I would have been sceptical. Go on, give it a try. We'll be here to hold your hand.

Cheers

noz

[Andmcit]

Thanks Noz for your detailed answer. Much appreciated!

I'm not afraid of dropping subframes as I've been here before with GS's.
I guess the Y piece I'm looking for is hidden on the middle blind section of the
cross tube!? That'd be typical.

The exhaust seems to be an odd arrangement (nothing new here either...)
where there's a solid section all the way through to a front subframe level
joint and separated just before the last back box in the same way as the
24v system.

Mind, I still don't fancy disturbing the height selector linkage or those dodgy
feed pipes even if I get past the exhaust!!

Guess I could take scary pictures to post here for the dodges and fixes
archive and earn notoriety n the process!

Andrew

[demag]

Steve (Steelcity UK) Has some good pictures of the anti sink on his Flickr page.

Do a search for anti sink once your on there and there's a few piccies come up.

[Andmcit]

Thanks Dave.

Seems like Steve has been here before me!!

Would you care to contribute comments on the renewal of the pipe from the
back of the anti sink sphere to it's other Y piece joint please Steelcityuk!?

I'm guessing from this pic:

http://www.flickr.com/photos/7328220@N02/1...in/photostream/

the end of the offending item I need to renew in my predicament is the pipe on the
eft of the pic half way up swinging down/round clockwise into the clipped joint?

Andrew

[steelcityuk]

Hi Andy,

The only 4.5mm pipe I know of is the anti sink pipe, on both XMs I've had it's been so badly corroded I've had to order a replacement from Pleiades. I usually (!) order a pipe made up at 19" from end to end.

http://www.flickr.com/photos/7328220@N02/1...57601606596399/

If you look at this picture, the anti sink sphere is connected to the 3 way block in the middle connector. The pipe snakes back towards the sphere without any support, maybe because it's short and 4.5mm it can do this without breaking.


http://www.flickr.com/photos/7328220@N02/1...57601599817022/

This is the 2.5 that I now have, the sphere is trapped by the corner gusset on the bracket. So what I did was to cut the gusset where it joins the bracket and then bend it back and forth until it fatigues and breaks off. See here -

http://www.flickr.com/photos/7328220@N02/1...57601599817022/

And here -

http://www.flickr.com/photos/7328220@N02/1...57601599817022/


I was prepared to make good the bracket with the MIG welder but it seems more than strong enough as it is. A good coating of Waxoyl will stop the bracket corroding too quick and help you squeeze the sphere into place. If you decide to cut the gusset be very careful of the ABS cable that goes into the suspension arm. It is reasonably easy to drop the subframe at just the left side but I didn't want to risk breaking any of the pipes in the process.

Hope that helps?

Steve.

[demag]

Andrew can you clarify that it is the antisink you are talking of? The sphere in your link is the rear centre suspension sphere (unless you are my indie of course! ).

[Andmcit]

That's brilliant Steve thanks; your pictures are VERY helpful.

From what I've just discovered it most definitely does break; it fatigued and cracked
open along the main unsupported straight length! It's great to see by removing the
heatshield/spare wheel carrier it looks as though this area is just about accessible from
underneath without dropping the subframe. That said it looks like the shield will
disintegrate if I even try bending it down out of the way and the securing bolts have
dissolved! Hohum.

I REALLY needed a clearer idea of the run on the pipe from the back of the centre
sphere to the middle portion of the cross tube. Looks like a job for a very short stubby
spanner as access looks typically horrible in there. Amazingly for a car that's been in
the North East all it's life the single joint on the rear of the centre sphere undid really
easily and must have only been finger tight!

What exactly holds the anti sink in place inside the bracket/gusset shoulder
- is it just sitting on the ledge or is it actually threaded on the pyramid shaped bracket?

All the best,
Andrew

[steelcityuk]

The Anti Sink sphere is a tightish fit behind the bracket, being boxed in on a few sides and it's held in place by the large nut on the outside of the bracket.

Steve.

[Andmcit]

Well, I've managed to get this sorted this evening!! Woooohoooo!!

I had a brainstorm epiphany moment where I remembered removing a rear subframe off a
late s2 car!

A good pal and fellow Citroen 'sufferer' arranged an interesting arrangement where he could
remove as much as he wanted/was able to unbolt for 40quid before the car was lifted out of
a garage yard/workshop for scrap. He asked me to exercise my killer car breaking ability to
strip it totally to the deck and some of the parts were a tad large/clunky to remove immediately
and the subframe is still there tucked way in the yard out of harm's way.

Got the offending pipe off the spare subframe and the car is up and running happily again with
no real harm done (except to my knuckles and fingernails... )

The offending pipe has a very sharp 'dig' by something into it's original shape with the effect
of the pipe requiring some previous owner 'attention'...

looks to me as though someone has tried soldering (badly) a repair/seal to the pipe which didn't
hold up to the pressure when it was put onto the high setting for the first time in new ownership!

Wonder what else may be lurking under the surface too...

This post has been edited by Andmcit on March 08, 2008 11:54 pm

[Peter.N.]

Well done! Gives you a great feeling of satisfaction when you conquer a problem like that. You still can't help looking underneath every now and again though, can you?

Peter.N.