Sphere Crud+ LHM Quantities

[Gregg1100]

Hi,
Before I fit the new green balls to car, how do I get the pipes to spheres clear of crud. ?? Also, does anyone know who does LHM in quantities larger than 1 litre, please.??
Greg
Xantia2 TD 1998

[CitroJim]

Hi Greg,

You need to treat your car to a dose of Hydraflush, available from GSF in 5L cans. Use it is place of LHM and run it for at least 1000 miles and then drain and refill with LHM. Clean the filters in the LHM reservoir before refilling with Hydraflush and clean them again before refilling with fresh LHM.

[jeremy]

Have you got crud in the pipes? Its not a common problem and if you have the question should be 'Where has it come from?'

Raising and lowering the suspension causes the LHM to flow round the system.

[Gregg1100]

Hi,
By crud, I mean dirty brownish coloured lhm. I can't quite grasp how oil would flow round system when there is only 1 supply pipe. If there were 2, yes, but as the system is under pressure all the time the car is on its legs, surely the oil that went into spheres on fitting, would stay there, under pressure?. I know the aerobics gets rid of the air, but wonder how it is physically done, with only 1 pipe.
As regards the LHM oil , I need to get a 5 litre can/bottles---all around my area only seem to do 1 litre cans. An expensive exercise at anything from £6-8 squids a throw.
Thanks,
Greg

[steelcityuk]

Carplan used to sell LHM in 5Ltr cans. My local factors used to sell it. Was about £16.

Steve.

[CitroJim]

Hi,
By crud, I mean dirty brownish coloured lhm.

Hydraflush will get rid of that a treat Greg The real crud you will find in the filters. They may well look as if they are wearing black fur coats

LHM flows around the system quite freely in fact, despite the small pipes and apparantly closed ends in the spheres. There is a lot of movement and circulation of the LHM that keeps it fresh in the spheres. LHM is at high pressure and in small pipes it can move at a fair old velocity. Sometimes you can hear it rushing along the pipes.

The only true dead ends are to the brake calipers; the reason why all brakes must be thoroughly bled after an LHM change.

My local factors want very nearly £30 now for a 5L can of Delphi LHM

[aerodynamica]

Hi Greg, there is one pipe in to each suspension unit true, but there is a certain degree of leakage allowed in the system ( the main suspension rams leak) and this loses LHM to the rubber dust covers to collect (their flexing feeds the leaked fluid back to the tank via little plastic tubes) so for any given loss due to this leakage the next time the car pumps up, a small amount of the LHM is new. You're quite right to question this: the fluid in the pipe to a sphere moves 'hydrostatically' and whether the car goes to full height or to lowest height, the bit of LHM between the height corrector and the sphere just goes back and forth - except for the long term leakage mentioned.

Spheres are dead easy to change out but there is a longer way to do it that bleeds through new fluid. What you do is have the rear of the car supported on axle stands, depressurise the circuit by setting to the low position, release the accumulator pressure by loosening the 12mm bolt on the regulator by half a turn. Unscrew the rear spheres as per normal(note it's often best to crack the initial grip they have with the car on high setting first then proceed to support it and lower) and have the new pair ready. what you do is to place a bucket under each suspension opening and check the height lever is still on LOW. Start the engine and tighten the regulator 12mm bolt wait till the regulator clicks and switch off the engine. With the buckets still in place, and the engine off slowly move the height control from low to middle and then intermediate (if necessary) and the pressurised LHM from the accumulator releases out the open ended cylinders and goes into the 2 buckets. Don't put the suspension lever on highest as this will dump the full accumulator contents too quickly. This moves all the old LHM out the stretch between the security valve and the spheres. The front pair can be done similarly without the axle stands - just on its tyres at low position. For the front you'd need small basins (?) inder each sphere housing as a bucket will not fit!

I'll admit I haven't done this since I had a BX ages ago and it's too difficult on the CX as you can't remove the rear spheres without first removing the rear cylinders! but well worth the effort to clear the whole circuit.

The Citroen GSA had a special K-shaped 4 way junction on the front hydraulics as the GSA didn't have a low setting on the height control lever. To depressurise the G front end you loosened an 11mm bleed nipple with a long rubber return line to the LHM tank fitted and the front end dropped. I'd consider getting a K-shaped junction and fitting a bleed on the unused 4th port for bleeding the front and rear axles individually and with no need to take off the spheres.