Spheres, Hydraflush and Brake Bleeding

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CitroJim
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Spheres, Hydraflush and Brake Bleeding

Post by CitroJim » 28 Jul 2008, 22:05

A question that is often asked is how to replace spheres, how to change the LHM, use Hydraflush and bleed brakes. This is a (hopefully) a concise guide to these three related jobs. I post here so that comments may be added and "peer reviewed" before it is moved to a more appropriate area of the forum.

Pre Requisites

Before starting, ensure you have the following tools and sundries:

A good sphere removal tool. Either the genuine Pleiades item or a "Xac Special" A tool is essential

Ramps and axle stands

A 12mm spanner for the bleed valve on the pressure regulator, a very good, slim 8mm ring spanner for the caliper bleed nipples and a very high quality 9mm flare nut spanner for the union on the anti sink sphere.

A clean 500ml glass jar and a length of plastic hose that is a snug fit on the bleed nipples.

A jar of clean petrol and a clean paint brush

A 4.5mm hydraulic seal for the Anti-Sink Sphere

A normal household broom (you'll see why later!)

Spheres

Starting with the most difficult, the rear corner spheres. These are often very tight and their removal MUST be carried out initially with the suspension on high and under full pressure to avoid damage to the suspension cylinders. The car MUST be very firmly supported and preferably on ramps. In any case, so supported that if it suddenly drops it won't crush you. So, up on ramps, engine running and suspension on high, you need to apply the sphere tool and "crack" each sphere off by about an eight to a quarter of a turn (i.e. just get them started). They will be tight and you may need to use your boot to get them moving. Once they are moving, put the suspension on low, depressurise by opening the 12mm bleed valve on the pressure regulator by no more than half a turn and go back, still ensuring the car is fully and safely supported and unscrew them fully. Be prepared for LHM spillage. Clean up, recover the old sphere seals if they got left behind in the groove on the sphere housing. Get your new sphere seals, dip them in clean LHM and place them in the groove, never place them on the sphere as they will not seat properly and may get cut. Screw the new sphere on hand-tight only.

Whilst you are there, do the Anti-Sink sphere. This is the one in the middle rear. before you can unscrew it, the small hydraulic pipe going into the rear of it MUST be undone and pulled out. For this you need the 9mm Flare Nut spanner. The union may be tight and take care not to round it off, hence the good spanner. A bit of Plus Gas is a good idea to help it along. Once the union nut is undone, pull the hydraulic pipe out of the sphere and note if the hydraulic seal came out with it. More than likely it will have stayed in the sphere. You MUST use a new one on installing the new sphere. Again, be prepared for a good spill of LHM.

You can now undo the old sphere off the bracket. It may be tight and the bracket is not that strong so take care. Strictly, this sphere does not need a new ring seal but it's not a bad idea to fit one. Screw the new sphere into the bracket, dip the new pipe hydraulic seal in LHM and fit it over the end of the pipe until it rests against the flare on the pipe. Push the pipe into the sphere and screw up the union. They don't need to be done mega tightly and it'll be about right when it is as far into the new sphere as it was in the old, usually thios depth can be gauged by where the rust begins on the union threads. On repressurising the system, check for leaks and if there is a weep, just nip the union up a touch until the leak stops.

They're the hard ones done. The front corners are easy, Just undo them (with the system on low and depressurised of course) be prepared for spillage, clean up, dip the new seals in LHM, place the seals in the grooves and screw the new sphers in hand-tight.

The same applies to the accumulator but access is often poor and you really need the front end up on ramps or stands to get good access to it to enable a good swing on the removal tool. The Accumulator is often very tight. Mind the radiator! Again, clean up, Dip the seal in LHM and place in the groove before screwing the sphere in hand-tight.

Finally, nip up the 12mm bleed valve, start up, allow pressure to come up, set on high, top up the LHM and do a really good session of Citarobics.



LHM Change

Set on low, depressurise, disconnect all the rubber pipes on top of the LHM reservoir. If the original clips are in place, carefully prise them apart with a scriber or small screwdriver before pulling the pipes off. They can be reused with care and need a small pair of pliers to clip them up again.

Undo the two 10mm nuts holding the reservoir and lift it out full of the old LHM. This is the easiest way. Release the spring clip across the top, lift out the filter head and place it in a clean receptacle to drain. I use the bottom of a 4 pint milk carton.

Pour the old LHM into a suitabel container ready for disposal at your local tip. Use the waste engine oil facility.

Clean out the LHM reservoir with clean, lint-free rag (blue paper is ideal) and them remove the two filters from the filter head and clean them in petrol. One is clipped on and is secured with a small "S" shaped wire clip and the other is secured with a bayonet fitting and is long and conical. It is easily missed as it lives up inside the suction tube. Wash them with a paint brush in petrol until they are spotless and leave to dry. The filter mesh is delicate so don't be rough with them.

Reassemble the LHM reservoir and refit to the car. The clips that hold the pipes on to the reservoir can be reused with care or "Jubilee" clips can be used instead.

Refill the reservoir with either LHM or Hydraflush. It'll take at least 4 litres.

Close the pressure regulator bleed valve, start up and set the suspension on high, top up the reservoir and do thorough citarobics. Recheck the level.

Bleeding Brakes

With the front wheels off and up on stands, locate the front caliper bleed nipples. Pop off their protective rubber caps, clean up around them, spray them with Plus Gas and carefully crack then open with your 8mm ring spanner. Nip them up again. leave the spanner on and place the plastic pipe on the nipple and lead it into a jamjar. Start up and apply the brakes by jamming the end broom between the seat and brake pedal (now you see what the broom is for!). Open the bleed nipple and watch LHM run ito the jamjar. When free of air and all the old, dirty fluid is flushed through, nip up the nipple, slip off the pipe, replace the rubber cap and repeat on the other side. Top up the LHM reservoir with the equivilent amount you bled out.

The rear brakes MUST be bled with the suspension set on high and with weight on the back wheels. On cars with alloy wheels it is sometimes possible (depending on the wheels) to get at the nipples without removing the wheels but on most, the wheels have to come off and that makes a problem of how to keep a load on the back wheels. Best is to do one wheel at a time and keep the other on the ground and thus loaded.

Do the same as for the front but do bleed at least 250mL of fluid out of each nipple as the rear brake lines are very long. Keep an eye on the LHM level and top up as necessary. You will know the level is low as the STOP light will come on. Don't let the level drop too low.

Job done. If you have used Hydraflush, leave it in for al least 1500 miles and them change for proper LHM it by repeating all the above procedure, including cleaning the filters again.

Recheck levels and do citarobics again.

Job's a good 'un

Please add to this as I'm sure to have forgotten something!

[Edited to correct the A/S sphere union nut size and hydraulic seal size :oops: ]
Last edited by CitroJim on 03 Aug 2008, 20:36, edited 3 times in total.
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Post by Ross_K » 28 Jul 2008, 22:27

Good write-up!

You should make it a sticky if you haven't done so already. 8)
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Post by CitroJim » 28 Jul 2008, 22:32

Ross_K wrote:You should make it a sticky if you haven't done so already. 8)


Good idea Ross :D Done!
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Post by admiral51 » 29 Jul 2008, 00:35

Im probably wrong and well prepared to be shot down in flames but i thought the Anti-Sink sphere was a 9mm nut :oops: :oops: :oops:
excellent write up Jim just need to link to some pics if poss :) :)

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Post by CitroJim » 29 Jul 2008, 07:48

admiral51 wrote: but I thought the Anti-Sink sphere was a 9mm nut :oops: :oops: :oops:


Thanks Colin, just the kind of thing I wanted...

Hence my request for "peer review" :wink: :lol:

It was all written from pure memory so the union nut may well be 9mm!

I'll take a check later and confirm.
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Post by RichardW » 29 Jul 2008, 09:59

Nice one Jim - worth noting though:

in order to fully depressure an Anti-sink car you need to select LOW with the engine running, and then leave it running for a minute or so before switching off and opening the bleed screw.

The bleed screw must NOT be removed, only slackened 1.5 turns max (I see reading it again you've got that, but some emphasis probably required...!)

It is possible to wiggle the LHM tank out without disconnecting the tubes - a bonus on hydractive cars with their 20 or so tubes!

I've never actually bled the front brakes, but presumably the job is made easier if you unclip the handbrake cables?

Should add plastic bag to the list of requirements - if changing a ruptured sphere it will spray LHM even though the susp is depressurised - if you put it in a poly bag this catches the spray!
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Post by CitroJim » 29 Jul 2008, 10:15

Thanks Richard, excellent :D

Good point on depressurising an Anti-Sink (I always forget :oops: )

A very good point on the bleed screw. Needs to be Bold and underlined!

I've only experience with Hydractive Activas and they seem to only have a couple more pipes on the reservoir compared to a non Hydractive. On the subject of Hydractive, it's worth noting that to replace the Hydractive Centre Spheres, proceed as for an acumulator sphere.

I prefer to pull the pipes and remove as a unit as it's a little less messy that way and I'm always worried about straining and damaging something; all mine seem to have pipes on the reservoir that are only just long enough :twisted: It's a personal preference really.

The fronts can be bled without removing the handbrake cables. The nipples are hard to find, being buried on the inner of the caliper. A slim spanner helps enormously. I recommend bleeding the fronts if only to expel the old LHM that gets trapped in there and never circulates. Little air ever seems to come out but still worth doing.

Good thought on the bag :lol: For the same reason, eye protection is not a bad idea either for protection from a squirter!
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Post by admiral51 » 31 Jul 2008, 20:45

This should be the LHM-Hydraflush Pic Link

Knew i had seen it somewhere :)

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Post by Toby_HDi » 31 Jul 2008, 21:38

Am now a bit concerned after reading around, that the pipe going into the Anti-Sink Sphere actually requires a 4.5mm pipe seal and not a 3.5mm?

Also, looking at the Citroen Service site, it appears it's 4.5mm.

I have bought the 3.5mm, can someone confirm which it is?

Other thing is, does the system not need priming (ie. pouring LHM down the pipe - not sure which one) after disconnecting the pipes?

Thanks
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Post by CitroJim » 01 Aug 2008, 21:59

admiral51 wrote:but i thought the Anti-Sink sphere was a 9mm nut


It is Colin, I'm the one who needs to be shot down in flames :lol: :oops:

The seal is a 4.5mm one as well. :oops:
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Post by CitroJim » 03 Aug 2008, 20:46

superloopy1 wrote:CJ - you've still got one reference to AS '8mm spanner' in your guide :lol:


Not any more :wink:

Pipe seals: These are little rubber tubes that fit over the end of the pipe and push on up to the "bump" in the pipe. Various sized ones are used all over the car but when dealing with sphers only on the antisink sphere and in the case of an Activa, on the Activa Accumulator sphere which looks exactly like an antisink sphere and in fact can use an antisink sphere as a temporary replacement.

Ramps: The easiest way to get the rear up on ramps is to have a big trolley jack and jack the car up until a ramp will slip under the wheels. I never like driving the car up onto them. They're only really needed at the rear and for the front you never need anything more than axle stands really.
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Post by Old-Guy » 13 Sep 2008, 21:55

Thanks for the excellent guide CitroJim!

With its help, I've just changed all 6 spheres and the LHM on our 1996 (95MY) Xantia 1.9TD estate. Bought in 2006 with genuine 67,000 on the clock with full Citroen main agent services to 65,000. Completely original including cam belt, auxiliary belt and rear tyres! If the LHM was ever changed, it was done without taking the tank out - seals still intact on retaining nuts. The rear spheres were certainly the originals, probably all of them were.

I bought new spheres on-line from GSF - cheaper even than trade price anywhere else! It wasn't clear if replacement spheres come with seals. They do (from GSF at least), except the 'anti-sink' sphere which doesn't need one (I used an old one to help stop the new sphere rusting onto the bracket) but you have to order the all-important 4.5mm pipe seal as a separate item - daft. GSF used to offer a download of a useful guide to which spheres fit what, but it's not on their new website. You can find a copy on my Xantia web pages.

I was very fortunate to have the use of a commercial workshop including a wheel-lift - once I got the rear spheres cracked, it really was an easy job. However, glass containers in the workshop are a complete no-no - I have a 330ml clear soft-drinks bottle with a hole drilled in the cap for the bleed tube (loose fit). Another one with large cap was used for petrol.

The rear spheres wouldn't shift with a strap wrench and 18" breaker bar - eventually the strap broke! A quick trip to our local Machine Mart for a chain filter wrench (CHT243) for under a fiver. The chain wrench 'cracked off' both rear spheres without too much trouble or force. I don't doubt that the job is easier with the special tools, but they are expensive - an hour's soak with 'Plus-Gas' and a bit of warmth seemed to be the key. Having done the rear end, I stupidly left the Accumulator sphere to last and then of course it wouldn't move! So I gave it a good squirt of Plus-Gas and left it to soak while I removed and cleaned the hydraulic reservoir - an hour or so later the Accumulator came off with the chain wrench without much trouble.

SUGGESTIONS

PREREQUISITES
To get inside the filters, you need a ½" paint brush. A soft toothbrush also speeds up cleaning old filters. Don't even think of using an air-line!

A good-sized pair of side (wire) cutters is what the professionals use on those hose clips - with a small screwdriver to prise open the clip when compressed.

A cheap 9mm ring spanner with a 5mm slot ground right through the end of the ring.

A cheap plastic kitchen jug (½L) or a new oil jug to fill the reservoir without spilling LHM everywhere.

METHOD
So the first thing to do (ideally the night before) is squirt some 'Plus-Gas' on the joints of the old rear spheres and on the pipe union in the front of the Anti-sink sphere and around the joint of the Accumulator sphere. Start by draining the old LHM and cleaning the tank. Next, do the front spheres (which should come off easily).

The Accumulator, Anti-sink and any 'blown' spheres will contain a fair bit of fluid. I had some empty plastic 2L lemonade bottles to hand; cut off about 5" from the base, they make a convenient 'pot' to catch the worst of any spillage. Once the old sphere is off, it can be inverted in the pot to drain. You'll need 3 or 4.

I couldn't buy or borrow (even from professional mechanics) a 9mm flare nut spanner anywhere - but after the 'Plus-Gas' treatment the nut in question moved easily with a 9mm open-end spanner (professional quality, snug fit, carefully positioned). This nut is a sod to get at, so I bought a cheap 9mm ring spanner, then ground a slot through it with the angle-grinder to make a cheap-and-nasty flare nut spanner. I used this only to wind the nut off (and on again), finally nipping it up tight with the 'pro' open-ender.

When I came to remove the LHM tank, I realised that if I had started by removing the air hose from the air cleaner it would be much easier. There is then room to unclip the hydraulic hose retainer from the side of the tank and push the hoses (once undone) out of the way while still held in the retainer.

From what was an almost-full 5L can of LHM there's about a cup-full left. If I'd had time to bleed the brakes (next job) as well, I would have needed another litre - I reckon you need to have at least 6L of 'green blood' on hand if you are also going to bleed the brakes (thus chucking the best part of another Litre of LHM).

Since I bought the car 2½ years ago, the ride has never been as good as I expected, even allowing for Gloucestershire's appalling rural roads, but a day's work and £150-worth of parts and LHM has transformed the ride - I wish I'd done it sooner!
Last edited by Old-Guy on 07 Jul 2009, 12:47, edited 1 time in total.
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Post by CitroJim » 13 Sep 2008, 22:26

Thanks a million for adding to this thread Old-Guy, it's improved no end as a result :D Oh and a warm welcome to the forum... Sounds like a very special car you have there.

That's a very good tip about making a 9mm flarenut spanner by grinding a slot in an ordinary 9mm ring. I find the best method to put the new A/S sphere on is to hold the flare nut steady with a spanner and wind the sphere onto it. You're right it is a sod access-wise :lol: A great tip too about using an old sphere seal on the A/S sphere :D
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Post by addo » 13 Sep 2008, 22:51

I know Gedore make an 8/9mm flare spanner - I've got one, bought not that many years ago. Should be even easier to find in the UK! (And not over $35 like it was here...)

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Post by Ross_K » 14 Sep 2008, 01:17

Draper make them as well. Part number is 04494.

http://www.drapertools-online.com/b2c/b ... kmno=04494

http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... 0276107635

Although the angle grinder method is cheaper if you happen to have one lying around... :P
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