Recepie to make Hydroflush

[lancia58]

I found the following in the following link

http://www.aussiefrogs.com/forum/showth ... Hydroflush" onclick="window.open(this.href);return false;

Is this safe and as efficient as the Original Hydroflush ?

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Recipe as provided by FatherGoose, expert in many things Citroenical.

Step 1/ Go to Autoparts store
Step 2/ Buy bottle of engine oil flush
Step 3/ Open LHM reservoir in engine bay
(I think you are probably getting the drift no)
Step 4/ Open engine oil flush bottle and pour entire contents into LHM reservoir
Step 5/ Close LHM reservoir and bonnet
Step 6/ Drive car for at least 1000km (not continuously of course) and put the hydraulics through a few gymastic lessons (ie full up and down cycles)

After all this, proceed to normal routine for a full change of LHM, including bleeding brake lines.
Did this to the XM and the gunk that came out was incredible.

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[addo]

I am not so convinced (and yes, I know the author well) that alternatives to dismantling and cleaning, achieve much success.

The first thing I suggest for anyone considering a big flush on a Xantia, is to renew the LHM return pipes - all of them, plus the supply pipe to the pump.

Then, sure, replace the LHM with new and bleed out your brakes to release at least 250ml per wheel. Next, remove the height correctors, dismantle, clean and reassemble. If you are really motivated, flushing out the anti-sink valves might provide extra cleaning benefits. I just cannot see how Hydraurinçage can get height correctors fully clean.

[Mandrake]

I'm not convinced that hydraflush is any better than flushing with normal LHM either addo. In NZ hydraflush was never available at any price (dealers and usual oil suppliers had never heard of it, privately importing it at great cost was the only choice) so I never used it, neither did my Dad who worked on Citroens since the 50's and had never heard of hydraflush until I read about it on the Internet...

The main thing is to get the sludge out of the system which is done by draining the existing oil. Because you can't drain all the oil from every nook and cranny (much like an auto gearbox) you then have to fill with sacrificial oil which will then dilute and collect what sludge remains and then drain it out and replace it a second time. If its really really dirty through years of neglect you might need to do this more than once. Whether that sacrificial oil is LHM or hydraflush probably doesn't matter much, and two flushes with cheaper LHM are almost certainly better than one flush with expensive hydraflush!

My previous Xantia came with red oil in the hydraulic system - I'm assuming some sort of Dexron 2, given the car came from Japan, and it took me many flushes to eradicate all traces of the red colour, about 3-4 full flushes over about 6 months from memory. Of course this is an extreme case.

I agree addo that height correctors need special attention, the way they are designed they can't help being sludge traps. Even after all the flushes above I stripped down the height correctors in that car and found them badly choked with particulate sludge. Surprisingly they were still working acceptably in that state, but they were certainly quicker and more accurate after cleaning - and will now no doubt work well for many more years than if I had not cleaned them.

(I hope the new owner appreciates all the preventative maintenance I did on that car. )

As you say brake lines need to be flushed too. I'm not sure that I would bother with anti-sink valves unless they are malfunctioning, as they're basically an on/off valve, unlike height correctors.

One other thing that might potentially benefit from a strip down and clean are the hydractive regulator blocks. I've partially disassembled one (removing the dampers) but never fully stripped one down, and I'm now seriously beginning to suspect the main shuttle valve in the block getting choked up with sludge or damaged pieces of o-ring could be one cause of unsolvable intermittent harsh ride that some HA2 Xantia's have despite so much else being done to them...

I have definitely seen evidence in both my Xantias that the shuttle valve in the block sometimes sticks even though I know the electrovalve is fine. It may be that they intermittently stick/jam or move to a partially open state rather than snapping back and forth efficiently between the hard and soft positions.

[Diabolical]

As you say brake lines need to be flushed too. I'm not sure that I would bother with anti-sink valves unless they are malfunctioning, as they're basically an on/off valve, unlike height correctors.

I would like to know how to this as mine malfunctioning, rear end drops down on regular basis, been doing it for few years wouldn't mind sorting it.